Some of the more common eye disease terms you may have heard about are included here.
Adie's Pupil - a pupil that does not react normally to bright light due to impaired nerve function; usually does not interfere substantially with vision
Amaurosis Fugax - temporary loss of vision in one eye; may be a sign of a transient ischemic attack (TIA) or an impending stroke
Amblyopia - the inability of an eye to see normally due to lack of input from the eye to the brain during childhood; also termed "lazy eye"
Aphakia - the absence of the eye's natural lens, usually after cataract surgery
Arcus Senilis - a hazy ring at the edge of the cornea where the iris meets the white of the eye; does not impair vision
Bell's Palsy - paralysis of the muscles on one side of the face due to nerve damage; usually temporary, but can interfere with blinking and protection of the eye
Blepharitis - inflammation of the eyelid; can cause irritation, discharge and even blurred vision
Chalazion - a bump in the eyelid caused by a clogged oil gland;may require surgical removal
Conjunctivitis - inflammation or infection of the conjunctiva, the mucous membrane covering the white of the eye
Corneal Edema - swelling of the cornea, often causing blurred vision
Corneal Erosion - spontaneous loss of a part of the surface "skin" of the eye-causes pain, light sensitivity and occasionally blurriness, and often occurs on awakening
Corneal Ulcer - a localized inflammation or infection of the cornea extending beneath the surface layer-must be treated immediately to prevent permanent damage
Central Retinal Artery Occlusion - blockage of the main blood supply to the eye often; causes blindness
Central Retinal Vein Occlusion - blockage of the main vein transporting blood away from the retina; causes hemorrhage in the retina and usually results in permanent vision impairment
Central Serous Retinopathy - spontaneous leakage of fluid into the retina, often in young, healthy people - cause is unknown
Dacryocystitis - infection in the tear sac adjacent to the nose-causes pain, swelling, tenderness and tearing
Dermatochalasis - excess or baggy skin on the eyelids, usually from loss of elastic tissue in the skin
Diplopia - double vision; usually caused by misaligned eyes
Drusen - discolored spots in the retina - can be an early sign of macular degeneration
Ectropion - loosening of the eyelid causing it to turn outward, away from the eye
Entropion - "collapsing" of the eyelid, causing the edge of the lid to turn inward, toward the eye-often results in discomfort due to eyelashes rubbing against the eye
Epiretinal Membrane - wrinkling of the surface of the retina; can cause blurriness or distortion in vision - severe cases can be treated with surgical removal
Esotropia - having an eye that turns inward
Exophthalmos - bulging forward of the eyes, sometimes caused by thyroid problems
Exotropia - having an eye that turns outward
Fuchs' Dystrophy - a deterioration of the cells in the cornea that maintain the cornea's clarity;often has no visual effect but may require a corneal transplant if severe
Hemianopia - the loss of one half of the visual field (left or right); usually affects both eyes and is often caused by brain injury, especially stroke
Hyphema - bleeding inside the eye, often due to an injury
Herpes Simplex - a cause of serious corneal infection - the same virus that causes cold sores
Herpes Zoster - "shingles" - the same virus that causes chicken pox, which can return and affect many areas of the body, including the eye
Iritis - inflammation inside the eye, primarily in the front of the eye - causes redness, pain, blurred vision and sensitivity to light in most cases
Keratitis - inflammation in the cornea-may cause scratchiness, pain, blurred vision and light sensitivity
Keratoconus - a progressive change in the shape of the cornea, creating a "cone" - like configuration and causing blurred vision - severe cases may require a corneal transplant
Macular Edema - swelling in the center of the retina caused by fluid leakage; results in blurred vision and visual distortion
Neovascularization - growth of new abnormal blood vessels - can occur at several locations in the eye
Nystagmus - oscillating movements of the eye
Ocular Migraine - a visual disturbance usually including an arc of zigzag light and blurry vision - disappears spontaneously and does not usually include a headache
Optic Neuritis - inflammation of the optic nerve, resulting in blurred vision or other visual disturbances - can be caused by multiple sclerosis
Papilledema - swelling of the optic nerve where it enters the eye - can be caused by increased fluid pressure around the brain
Pinguecula - a thickening of the white of the eye;often caused by chronic irritation
Pterygium - growth of tissue from the white of the eye over the cornea - may interfere with vision if it nears the center of the cornea
Ptosis - droopiness of the eyelid - may result from nerve or muscle damage, and sometimes requires surgical correction
Retinal Detachment - separation of the retina from its normal location covering the inner surface of the back portion of the eye
Rubeosis - growth of abnormal blood vessels on the iris
Scotoma - a blind spot
Strabismus - any misalignment of the eye
Stye - an acute inflammation of a gland at the base of an eyelash, caused by bacterial infection.
Trichiasis - abnormal eyelash growth, usually pointing toward the eye
Uveitis - inflammation of the interior of the eye
Vitreous Detachment - separation of the vitreous gel from the back of the eye - a common occurrence which can result in sudden floaters and occasionally causes a tear in the retina
Visual Simulation
On this page we will look at the same scene through the eyes of four different people, one with normal vision, and the others with different vision problems. This should give you a feel for how these people see the world.
Normal
Normal
This is the scene as viewed through normal eyes. Things near and far appear in focus.
Nearsightedness
This is the scene through nearsighted eyes. Close up objects like the chairs are in focus, while objects far away like the islands are blurry.
Farsightedness
This is the scene through farsighted eyes. Objects far away like the islands are in focus, but close up objects, like the chairs are blurry.
Astigmatism
This is the scene through astigmatic eyes. This is like a combination of both near and farsightedness, making all objects blurry.
Eye Cancer.
What Is Eye Cancer?
An eye cancer is a cancer that starts in the eye. There are different types of eye cancers. To understand eye cancers, it helps to know something about the normal structure and function of the eye.
Parts of the eye
The eye has 3 major parts: the eyeball (globe), the orbit, and the adnexal structures.
Eyeball
The main part of the eye is the eyeball (also known as the globe), which is filled with a jelly-like material called vitreous humor. The eyeball has 3 main layers -- the sclera, the uvea, and the retina.
Sclera: The sclera is the tough, white, outer covering over most of the eyeball. In the front of the eye it is continuous with the cornea, which is clear to let light through.
Uvea: The uvea is the middle layer of the eyeball. It is where most melanomas of the eye develop. The uvea has 3 main parts:
The iris is the colored or pigmented part of the eye. It surrounds the pupil, the small opening that allows light to enter the eyeball.
The choroid is a thin, pigmented layer lining the eyeball that nourishes the retina and the front of the eye with blood.
The ciliary body contains the muscles inside the eye that change the shape of the lens so that the eye can focus on near or distant objects. It also contains cells that make aqueous humor, the clear fluid in the front of the eye between the cornea and the lens.
Retina: The retina is the inner layer of cells in the back of the eye. It is made up of specialized nerve cells that are sensitive to light. These light-sensing cells are connected to the brain by the optic nerve. Light enters the eye and passes through the lens, which focuses it on the retina. The pattern of light (image) appearing on the retina is sent through the optic nerve to an area of the brain called the visual cortex, allowing us to see.
Cancers that affect the eyeball are called intraocular (within the eye) cancers.
Orbit
The second part of the eye, called the orbit, consists of the tissues surrounding the eyeball. These tissues include muscles that make the globe move in different directions and the nerves attached to the eye.
Cancers of these tissues are called orbital cancers.
Adnexal structures
Finally, there are adnexal (accessory) structures such as the eyelids and tear glands.
Cancers that develop in these tissues are called adnexal cancers.
Cancers in the eye (intraocular cancers)
Two types of cancers can be found in the eye.
Primary intraocular cancers are cancers that start inside the eyeball. In adults, melanoma is the most common primary intraocular cancer, followed by primary intraocular lymphoma.
In children, retinoblastoma (a cancer arising from cells in the retina) is the most common primary intraocular cancer, and medulloepithelioma is the next most common (but it is extremely rare). These cancers are discussed in our separate document, Retinoblastoma.
Secondary intraocular cancers are cancers that have spread to the eye from another part of the body. These are not truly "eye cancers," but they are actually more common than primary intraocular cancers. The most common cancers that spread to the eye are breast and lung cancers. Usually these cancers spread to the part of the eyeball called the uvea. For more information on these types of cancers, refer to the specific American Cancer Society documents on these cancers.
Intraocular melanoma (melanoma of the eye)
Intraocular melanoma is the most common type of cancer that develops within the eyeball in adults, but it is still fairly rare. Melanomas of the skin are much more common than intraocular melanomas.
Melanomas develop from pigment-producing cells called melanocytes. When melanoma develops in the eyeball, it is usually in the uvea, which is why these cancers are also called uveal melanomas. About 9 out of 10 intraocular melanomas develop in the choroid. Choroid cells have the same kind of pigment as melanocytes in the skin, so it is not surprising that these cells sometimes form melanomas.
Nearly all of the remaining intraocular melanomas start in the iris. These are the easiest for the patient and doctor to see because they often arise in a pigmented spot on the iris that has been present for many years and then begins to grow. These melanomas usually are fairly slow growing, and they rarely spread to other parts of the body. For these reasons, people with iris melanomas generally have a good prognosis (outlook).
Intraocular melanomas are generally made up of 2 different kinds of cells.
spindle cells: These are long, thin cells.
epithelioid cells: These cells are almost round but with some straight edges.
Most tumors are composed of both kinds of cells. The outlook is better if the tumors are mostly spindle cells as opposed to mostly epithelioid cells. Epithelioid tumors are more likely to metastasize (spread) to distant sites. If you have intraocular melanoma, your doctor can tell you which type of cells were found.
Primary intraocular lymphoma (lymphoma of the eye)
Lymphoma is a type of cancer that starts in immune system cells called lymphocytes. It usually starts in lymph nodes, which are bean-sized collections of immune system cells. But lymphomas can also start in internal organs such as the stomach, lungs, and rarely in the eyes.
There are 2 main types of lymphoma -- Hodgkin disease and non-Hodgkin lymphoma. Primary intraocular lymphoma is always a non-Hodgkin lymphoma. Most people with primary intraocular lymphoma are elderly or have immune system problems such as the acquired immunodeficiency syndrome (AIDS).
Orbital and adnexal cancers
Cancers of the orbit and adnexa develop from tissues such as muscle, nerve, and skin around the eyeball and are just like their counterparts in other parts of the body. These are described in other American Cancer Society documents on cancers of muscle, nerve, skin, etc. For example, cancers of the eyelid are usually skin cancers, which are described in our documents on skin cancers (Melanoma Skin Cancer and Skin Cancer: Basal and Squamous Cell)
An eye cancer is a cancer that starts in the eye. There are different types of eye cancers. To understand eye cancers, it helps to know something about the normal structure and function of the eye.
Parts of the eye
The eye has 3 major parts: the eyeball (globe), the orbit, and the adnexal structures.
Eyeball
The main part of the eye is the eyeball (also known as the globe), which is filled with a jelly-like material called vitreous humor. The eyeball has 3 main layers -- the sclera, the uvea, and the retina.
Sclera: The sclera is the tough, white, outer covering over most of the eyeball. In the front of the eye it is continuous with the cornea, which is clear to let light through.
Uvea: The uvea is the middle layer of the eyeball. It is where most melanomas of the eye develop. The uvea has 3 main parts:
The iris is the colored or pigmented part of the eye. It surrounds the pupil, the small opening that allows light to enter the eyeball.
The choroid is a thin, pigmented layer lining the eyeball that nourishes the retina and the front of the eye with blood.
The ciliary body contains the muscles inside the eye that change the shape of the lens so that the eye can focus on near or distant objects. It also contains cells that make aqueous humor, the clear fluid in the front of the eye between the cornea and the lens.
Retina: The retina is the inner layer of cells in the back of the eye. It is made up of specialized nerve cells that are sensitive to light. These light-sensing cells are connected to the brain by the optic nerve. Light enters the eye and passes through the lens, which focuses it on the retina. The pattern of light (image) appearing on the retina is sent through the optic nerve to an area of the brain called the visual cortex, allowing us to see.
Cancers that affect the eyeball are called intraocular (within the eye) cancers.
Orbit
The second part of the eye, called the orbit, consists of the tissues surrounding the eyeball. These tissues include muscles that make the globe move in different directions and the nerves attached to the eye.
Cancers of these tissues are called orbital cancers.
Adnexal structures
Finally, there are adnexal (accessory) structures such as the eyelids and tear glands.
Cancers that develop in these tissues are called adnexal cancers.
Cancers in the eye (intraocular cancers)
Two types of cancers can be found in the eye.
Primary intraocular cancers are cancers that start inside the eyeball. In adults, melanoma is the most common primary intraocular cancer, followed by primary intraocular lymphoma.
In children, retinoblastoma (a cancer arising from cells in the retina) is the most common primary intraocular cancer, and medulloepithelioma is the next most common (but it is extremely rare). These cancers are discussed in our separate document, Retinoblastoma.
Secondary intraocular cancers are cancers that have spread to the eye from another part of the body. These are not truly "eye cancers," but they are actually more common than primary intraocular cancers. The most common cancers that spread to the eye are breast and lung cancers. Usually these cancers spread to the part of the eyeball called the uvea. For more information on these types of cancers, refer to the specific American Cancer Society documents on these cancers.
Intraocular melanoma (melanoma of the eye)
Intraocular melanoma is the most common type of cancer that develops within the eyeball in adults, but it is still fairly rare. Melanomas of the skin are much more common than intraocular melanomas.
Melanomas develop from pigment-producing cells called melanocytes. When melanoma develops in the eyeball, it is usually in the uvea, which is why these cancers are also called uveal melanomas. About 9 out of 10 intraocular melanomas develop in the choroid. Choroid cells have the same kind of pigment as melanocytes in the skin, so it is not surprising that these cells sometimes form melanomas.
Nearly all of the remaining intraocular melanomas start in the iris. These are the easiest for the patient and doctor to see because they often arise in a pigmented spot on the iris that has been present for many years and then begins to grow. These melanomas usually are fairly slow growing, and they rarely spread to other parts of the body. For these reasons, people with iris melanomas generally have a good prognosis (outlook).
Intraocular melanomas are generally made up of 2 different kinds of cells.
spindle cells: These are long, thin cells.
epithelioid cells: These cells are almost round but with some straight edges.
Most tumors are composed of both kinds of cells. The outlook is better if the tumors are mostly spindle cells as opposed to mostly epithelioid cells. Epithelioid tumors are more likely to metastasize (spread) to distant sites. If you have intraocular melanoma, your doctor can tell you which type of cells were found.
Primary intraocular lymphoma (lymphoma of the eye)
Lymphoma is a type of cancer that starts in immune system cells called lymphocytes. It usually starts in lymph nodes, which are bean-sized collections of immune system cells. But lymphomas can also start in internal organs such as the stomach, lungs, and rarely in the eyes.
There are 2 main types of lymphoma -- Hodgkin disease and non-Hodgkin lymphoma. Primary intraocular lymphoma is always a non-Hodgkin lymphoma. Most people with primary intraocular lymphoma are elderly or have immune system problems such as the acquired immunodeficiency syndrome (AIDS).
Orbital and adnexal cancers
Cancers of the orbit and adnexa develop from tissues such as muscle, nerve, and skin around the eyeball and are just like their counterparts in other parts of the body. These are described in other American Cancer Society documents on cancers of muscle, nerve, skin, etc. For example, cancers of the eyelid are usually skin cancers, which are described in our documents on skin cancers (Melanoma Skin Cancer and Skin Cancer: Basal and Squamous Cell)
Blurry Vision
Blurry vision can be caused by several different things.
Almost everybody has experienced it at some point in there lives, and often blurry vision is caused by our own stupidity. Not always, but most of the time. That’s probably why I’ve experienced blurry vision several times in my own life.
The easiest way to get blurry vision is to walk around without your glasses on. This may sound stupid, but lots of people refuse to go to the eye doctor and get their eyes checked or re-checked. The result: blurry vision.
Common Blurry Vision Causes
You can also get blurry vision from consuming too much alcohol or taking illegal drugs. I’m sure most of you have had a few too many beers and had your vision go wacko as a result. I’m also sure that none of you have ever done illegal drugs, so you wouldn’t have any first hand experience with blurry vision because of it. Guess you’ll just have to take my word for it.
If you have high blood pressure you may experience some blurry vision. This is explained in depth in the articles on high blood pressure found on this site.
Blurry vision can also be a result of over exerting yourself. For instance, if you go jogging and push your body to the limits, it’s only a matter of time before you aren’t getting enough oxygen to fuel your body and so your vision may blur.
If you have a cold or viral infection you may get blurry vision in short doses. If your body is fighting off an infection of some type, it saps your resources and sometimes you end up with blurry vision. Do yourself a favour and get some rest.
Some prescription drugs have the added bonus of giving you blurry vision. If you are experiencing blurry vision from a prescription drug, you might want to consult your doctor. They may change your prescription to one that doesn’t give you blurry vision.
I suffer from migraine head aches occasionally. Often, when I’m suffering from one of these episodes, I get blurry vision.
You may experience blurry vision at steep altitudes. I’m sure that most of you don’t mountain climb so you will never have to worry about this side effect. You never know for sure though, so I thought I’d add it in for good measure.
I’m also afraid of heights. If I’m up high (high for me may not be high for you. Anything over ten feet is a major accomplishment for me. I’m such a wimp.) I tend to get blurry vision. Funny how the body works. I’m afraid of heights because I don’t want to fall, so naturally my body gives me blurry vision. Who says nature doesn’t make mistakes?
Sometimes blurry vision could be a symptom of a more serious health problem. If you suffer from blurry vision frequently, you should see a doctor and get checked out. Perhaps, you might also think about seeing your friendly neighbourhood eye doctor for good measure.
Almost everybody has experienced it at some point in there lives, and often blurry vision is caused by our own stupidity. Not always, but most of the time. That’s probably why I’ve experienced blurry vision several times in my own life.
The easiest way to get blurry vision is to walk around without your glasses on. This may sound stupid, but lots of people refuse to go to the eye doctor and get their eyes checked or re-checked. The result: blurry vision.
Common Blurry Vision Causes
You can also get blurry vision from consuming too much alcohol or taking illegal drugs. I’m sure most of you have had a few too many beers and had your vision go wacko as a result. I’m also sure that none of you have ever done illegal drugs, so you wouldn’t have any first hand experience with blurry vision because of it. Guess you’ll just have to take my word for it.
If you have high blood pressure you may experience some blurry vision. This is explained in depth in the articles on high blood pressure found on this site.
Blurry vision can also be a result of over exerting yourself. For instance, if you go jogging and push your body to the limits, it’s only a matter of time before you aren’t getting enough oxygen to fuel your body and so your vision may blur.
If you have a cold or viral infection you may get blurry vision in short doses. If your body is fighting off an infection of some type, it saps your resources and sometimes you end up with blurry vision. Do yourself a favour and get some rest.
Some prescription drugs have the added bonus of giving you blurry vision. If you are experiencing blurry vision from a prescription drug, you might want to consult your doctor. They may change your prescription to one that doesn’t give you blurry vision.
I suffer from migraine head aches occasionally. Often, when I’m suffering from one of these episodes, I get blurry vision.
You may experience blurry vision at steep altitudes. I’m sure that most of you don’t mountain climb so you will never have to worry about this side effect. You never know for sure though, so I thought I’d add it in for good measure.
I’m also afraid of heights. If I’m up high (high for me may not be high for you. Anything over ten feet is a major accomplishment for me. I’m such a wimp.) I tend to get blurry vision. Funny how the body works. I’m afraid of heights because I don’t want to fall, so naturally my body gives me blurry vision. Who says nature doesn’t make mistakes?
Sometimes blurry vision could be a symptom of a more serious health problem. If you suffer from blurry vision frequently, you should see a doctor and get checked out. Perhaps, you might also think about seeing your friendly neighbourhood eye doctor for good measure.
MACULAR HOLE
You should read this information sheet in conjunction with the vitrectomy information sheet.
A macular hole occurs in the macular region of the retina. The retina is the seeing part of the eye. A macular hole tends to develop around the age of 65 and is 4 times more common in females. It is thought to be due to a transparent membrane on the surface of the retina, which contracts and causes a stretching progressive enlargement of a hole in the most sensitive part of the retina. Eventually fluid can collect beneath the retina causing further deterioration of vision.
Natural course
There are 4 stages of macular hole -( 1 to 4).
80 to 90% progress from stage 2 onwards.
60% of eyes with macular hole eventually only see the top or the second line ( the largest letters) on the test chart.
Less than 10% retain driving vision in the eye with macula hole.
A macular hole can develop in the second eye.
The risk to the second eye is 7%, by 6 years later.
It is extremely rare for the condition to recover without treatment( 3%).
Treatment
The aim of treatment is to peel away the membrane and seal the hole. The procedure usually requires a gas bubble to be placed inside the eye to seal the hole. Afterwards strict posturing is essential for the success of the operation.
Results
The best results are achieved in patients who have not had symptoms for long that is less than 6 months do better than less than a year. Similarly the better the vision the better the results.
Furthermore the more advanced stages do worse.
For example: For stage 2 there is 90% success for closure of the hole. For stage 3 to 4, there is 30 to 70% successful closure.
For a large group of patients receiving treatment, I would expect half the patients to report an improvement in vision. Half would report no change and 5% would be worse.
Late problems
Macular holes sometimes reopen, then further surgery can be considered.
Within 2 years of surgery it is very likely that a cataract would have developed, requiring surgery.
Rarely retinal detachment occurs.
A macular hole occurs in the macular region of the retina. The retina is the seeing part of the eye. A macular hole tends to develop around the age of 65 and is 4 times more common in females. It is thought to be due to a transparent membrane on the surface of the retina, which contracts and causes a stretching progressive enlargement of a hole in the most sensitive part of the retina. Eventually fluid can collect beneath the retina causing further deterioration of vision.
Natural course
There are 4 stages of macular hole -( 1 to 4).
80 to 90% progress from stage 2 onwards.
60% of eyes with macular hole eventually only see the top or the second line ( the largest letters) on the test chart.
Less than 10% retain driving vision in the eye with macula hole.
A macular hole can develop in the second eye.
The risk to the second eye is 7%, by 6 years later.
It is extremely rare for the condition to recover without treatment( 3%).
Treatment
The aim of treatment is to peel away the membrane and seal the hole. The procedure usually requires a gas bubble to be placed inside the eye to seal the hole. Afterwards strict posturing is essential for the success of the operation.
Results
The best results are achieved in patients who have not had symptoms for long that is less than 6 months do better than less than a year. Similarly the better the vision the better the results.
Furthermore the more advanced stages do worse.
For example: For stage 2 there is 90% success for closure of the hole. For stage 3 to 4, there is 30 to 70% successful closure.
For a large group of patients receiving treatment, I would expect half the patients to report an improvement in vision. Half would report no change and 5% would be worse.
Late problems
Macular holes sometimes reopen, then further surgery can be considered.
Within 2 years of surgery it is very likely that a cataract would have developed, requiring surgery.
Rarely retinal detachment occurs.
what is blind spot in human eye ?
Blind Spot
It is a spot at which the optic nerve enters the eye and is insensitive to light and hence the name.
The human eye has a blind spot in its field of vision. This lies on the point of the retina where the optic nerve leads back into the brain. The retina has no light-sensitive rods or cones at this point, and so a small object in the field of vision's blind spot becomes invisible. (Dr.Rashmi Sudha)
It is a spot at which the optic nerve enters the eye and is insensitive to light and hence the name.
The human eye has a blind spot in its field of vision. This lies on the point of the retina where the optic nerve leads back into the brain. The retina has no light-sensitive rods or cones at this point, and so a small object in the field of vision's blind spot becomes invisible. (Dr.Rashmi Sudha)
Eye Twitching or Blepharospasm
Eye Twitching, or Blepharospasm, is involuntary eyelid twitching. It is also referred to as an eye muscle spasm. The term blepharospasm really applies to any abnormal blinking or involuntary eye twitching of the eyelids caused by uncontrolled contractions of the muscles around the eyelids.
Sometimes people experience the twitching under the eye and others may experience the twitching in their right eye or twitching in their left eye. In simple terms it is a blinking disorder. One type of blepharospasm, Benign Essential Blepharospasm or BEB is a blinking disorder that is not life threatening and has an unknown causes. Other types of blepharospasm may be associated with dry eyes, Tourette’s Syndrome or other neurological problems and may be more serious. In general, patients experiencing blepharospasm have normal eyes and any disturbance in their vision is due to the forced closure of the eyelids. BEB should not be confused with ptosis, or a drooping of the eyelids that may be caused by a weakness or paralysis of the muscle in the upper eyelid. Minor eye twitches usually do not worsen. If they do worsen or persist, it is important to seek the advice of an eye care professional.
Blepharospasm usually starts with abnormal or excessive blinking that is accompanied by general eye irritation. Early on, the excessive blinking may only occur as a result of being exposed to bright lights, being tired or if you are under a great deal of stress. The frequency of the eye spasms may increase throughout the day. Sometimes the eye spasm may resolve during sleep and not even occur after a sound night’s sleep until you have been awake for many hours. As the condition worsens, the spasms tend to get stronger and may result in the eyelids being tightly shut for a few hours at time making it impossible for the person to see.
Some alternative names:
eye muscle twitch, eyelid twitch, eyelid spasm, eye spasm
Is it a constant eye twitch or does it come and go?
Eye Twitching, for most people, is just annoying, involuntary eye muscles spasm surrounding the eye that go away over time. The spasms usually occur a few times and come back. Spasms that cause twitching on one side of the face are known as hemifacial spasms. These are typically due to some form of irritation to the facial nerve This type of spasm requires visiting your family doctor who may refer you to a neurologist or an eye care professional, in order to determine the cause and what treatment might be appropriate. If your eye is twitching, then you should read about how to stop eye from twitching.
Sometimes people experience the twitching under the eye and others may experience the twitching in their right eye or twitching in their left eye. In simple terms it is a blinking disorder. One type of blepharospasm, Benign Essential Blepharospasm or BEB is a blinking disorder that is not life threatening and has an unknown causes. Other types of blepharospasm may be associated with dry eyes, Tourette’s Syndrome or other neurological problems and may be more serious. In general, patients experiencing blepharospasm have normal eyes and any disturbance in their vision is due to the forced closure of the eyelids. BEB should not be confused with ptosis, or a drooping of the eyelids that may be caused by a weakness or paralysis of the muscle in the upper eyelid. Minor eye twitches usually do not worsen. If they do worsen or persist, it is important to seek the advice of an eye care professional.
Blepharospasm usually starts with abnormal or excessive blinking that is accompanied by general eye irritation. Early on, the excessive blinking may only occur as a result of being exposed to bright lights, being tired or if you are under a great deal of stress. The frequency of the eye spasms may increase throughout the day. Sometimes the eye spasm may resolve during sleep and not even occur after a sound night’s sleep until you have been awake for many hours. As the condition worsens, the spasms tend to get stronger and may result in the eyelids being tightly shut for a few hours at time making it impossible for the person to see.
Some alternative names:
eye muscle twitch, eyelid twitch, eyelid spasm, eye spasm
Is it a constant eye twitch or does it come and go?
Eye Twitching, for most people, is just annoying, involuntary eye muscles spasm surrounding the eye that go away over time. The spasms usually occur a few times and come back. Spasms that cause twitching on one side of the face are known as hemifacial spasms. These are typically due to some form of irritation to the facial nerve This type of spasm requires visiting your family doctor who may refer you to a neurologist or an eye care professional, in order to determine the cause and what treatment might be appropriate. If your eye is twitching, then you should read about how to stop eye from twitching.
How Does The Human Eye Work?
The individual components of the eye work in a manner similar to a camera. Each part plays a vital role in providing clear vision. So think of the eye as a camera with the cornea, behaving much like a lens cover. As the eye's main focusing element, the cornea takes widely diverging rays of light and bends them through the pupil, the dark, round opening in the center of the colored iris. The iris and pupil act like the aperture of a camera.
Next in line is the lens which acts like the lens in a camera, helping to focus light to the back of the eye. Note that the lens is the part which becomes cloudy and is removed during cataract surgery to be replaced by an artificial implant nowadays.
Anterior Chamber
The cavity in the front part of the eye between the lens and cornea is called the Anterior Chamber. It is filled with Aqueous, a water-like fluid. This fluid is produced by the ciliary body and drains back into the blood circulation through channels in the chamber angle. It is turned over every100 minutes.
Chamber Angle
Located at the junction of the cornea, iris, and sclera, the anterior chamber angle extends 360 degrees at the perimeter of the iris. Channels here allow aqueous fluid to drain back into the blood circulation from the eye. May be obstructed in glaucoma.
Ciliary Body
A structure located behind the iris (rarely visible) which produces aqueous fluid that fills the front part of the eye and thus maintains the eye pressure. It also allows focusing of the lens.
Conjunctiva
A thin lining over the sclera, or white part of the eye. This also lines the inside of the eyelids.Cell in the conjunctiva produce mucous, which helps to lubricate the eye.
Cornea
The transparent, outer "window" and primary focusing element of the eye. The outer layer of the cornea is known as epithelium. Its main job is to protect the eye. The epithelium is made up of transparent cells that have the ability to regenerate quickly. The inner layer of the cornea is also made up of transparent tissue, which allows light to pass.
Hyaloid Canal
A narrow channel that runs from the optic disc to the back surface of the lens. It serves an embryologic function prior to birth but none afterwards.
Iris
Inside the anterior chamber is the iris. This is the part of the eye which is responsible for one's eye color. It acts like the diaphragm of a camera, dilating and constricting the pupil to allow more or less light into the eye.
Pupil
The dark opening in the center of the colored iris that controls how much light enters the eye.The colored iris functions like the iris of a camera, opening and closing, to control the amount of light entering through the pupil.
Lens
The part of the eye immediately behind the iris that performs delicate focusing of light rays upon the retina. In persons under 40, the lens is soft and pliable, allowing for fine focusing from a wide variety of distances. For individuals over 40, the lens begins to become less pliable, making focusing upon objects near to the eye more difficult. This is known as presbyopia.
Macula
The part of the retina which is most sensitive, and is responsible for the central (or reading)vision. It is located near the optic nerve directly at the back of the eye (on the inside). This area is also responsible for color vision.
Optic Disc
The position in the back of the eye where the nerve (along with an artery and vein) enters the eye corresponds to the "blind spot" since there are no rods or cones in these location. Normally, a person does not notice this blind spot since rapid movements of the eye and processing in the brain compensate for this absent information. This is the area that the ophthalmologist studies when evaluating a patient for glaucoma, a condition where the optic nerve becomes damaged often due to high pressure within the eye. As it looks like a cupwhen viewed with an ophthalmoscope, it is sometimes referred to as the Optic Cup.
Optic Nerve
The optic nerve is the structure which takes the information from the retina as electrical signals and delivers it to the brain where this information is interpreted as a visual image. The optic nerve consists of a bundle of about one million nerve fibers.
Retina
The membrane lining the back of the eye that contains photoreceptor cells. These
photoreceptor nerve cells react to the presence and intensity of light by sending an impulse to the brain via the optic nerve. In the brain, the multitude of nerve impulses received from the photoreceptor cells in the retina are assimilated into an image.
Sclera
The white, tough wall of the eye. Few diseases affect this layer. It is covered by the episclera (a fibrous layer between the conjunctiva and sclera ) and conjunctiva, and eye muscles are connected to this.
Vitreous
Next in our voyage through the eye is the vitreous. This is a jelly-like substance that fills the body of the eye. It is normally clear. In early life, it is firmly attached to the retina behind it.With age, the vitreous becomes more water-like and may detach from the retina. Often, little clumps or strands of the jelly form and cast shadows which are perceived as "floaters". While frequently benign, sometimes floaters can be a sign of a more serious condition such as a retinal tear or detachment and should be investigated with a thorough ophthalmologic
examination.
Next in line is the lens which acts like the lens in a camera, helping to focus light to the back of the eye. Note that the lens is the part which becomes cloudy and is removed during cataract surgery to be replaced by an artificial implant nowadays.
The very back of the eye is lined with a layer called the retina which acts very much like the film of the camera. The retina is a membrane containing photoreceptor nerve cells that lines the inside back wall of the eye. The photoreceptor nerve cells of the retina change the light rays into electrical impulses and send them through the optic nerve to the brain where an image is perceived. The center 10% of the retina is called the macula. This is responsible for
your sharp vision, your reading vision. The peripheral retina is responsible for the peripheral vision. As with the camera, if the "film" is bad in the eye (i.e. the retina), no matter how good the rest of the eye is, you will not get a good picture.
The human eye is remarkable. It accommodates to changing lighting conditions and focuses light rays originating from various distances from the eye. When all of the components of the eye function properly, light is converted to impulses and conveyed to the brain where an image is perceived.
Glossary of Eye Terms:
your sharp vision, your reading vision. The peripheral retina is responsible for the peripheral vision. As with the camera, if the "film" is bad in the eye (i.e. the retina), no matter how good the rest of the eye is, you will not get a good picture.
The human eye is remarkable. It accommodates to changing lighting conditions and focuses light rays originating from various distances from the eye. When all of the components of the eye function properly, light is converted to impulses and conveyed to the brain where an image is perceived.
Glossary of Eye Terms:
Anterior Chamber
The cavity in the front part of the eye between the lens and cornea is called the Anterior Chamber. It is filled with Aqueous, a water-like fluid. This fluid is produced by the ciliary body and drains back into the blood circulation through channels in the chamber angle. It is turned over every100 minutes.
Chamber Angle
Located at the junction of the cornea, iris, and sclera, the anterior chamber angle extends 360 degrees at the perimeter of the iris. Channels here allow aqueous fluid to drain back into the blood circulation from the eye. May be obstructed in glaucoma.
Ciliary Body
A structure located behind the iris (rarely visible) which produces aqueous fluid that fills the front part of the eye and thus maintains the eye pressure. It also allows focusing of the lens.
Conjunctiva
A thin lining over the sclera, or white part of the eye. This also lines the inside of the eyelids.Cell in the conjunctiva produce mucous, which helps to lubricate the eye.
Cornea
The transparent, outer "window" and primary focusing element of the eye. The outer layer of the cornea is known as epithelium. Its main job is to protect the eye. The epithelium is made up of transparent cells that have the ability to regenerate quickly. The inner layer of the cornea is also made up of transparent tissue, which allows light to pass.
Hyaloid Canal
A narrow channel that runs from the optic disc to the back surface of the lens. It serves an embryologic function prior to birth but none afterwards.
Iris
Inside the anterior chamber is the iris. This is the part of the eye which is responsible for one's eye color. It acts like the diaphragm of a camera, dilating and constricting the pupil to allow more or less light into the eye.
Pupil
The dark opening in the center of the colored iris that controls how much light enters the eye.The colored iris functions like the iris of a camera, opening and closing, to control the amount of light entering through the pupil.
Lens
The part of the eye immediately behind the iris that performs delicate focusing of light rays upon the retina. In persons under 40, the lens is soft and pliable, allowing for fine focusing from a wide variety of distances. For individuals over 40, the lens begins to become less pliable, making focusing upon objects near to the eye more difficult. This is known as presbyopia.
Macula
The part of the retina which is most sensitive, and is responsible for the central (or reading)vision. It is located near the optic nerve directly at the back of the eye (on the inside). This area is also responsible for color vision.
Optic Disc
The position in the back of the eye where the nerve (along with an artery and vein) enters the eye corresponds to the "blind spot" since there are no rods or cones in these location. Normally, a person does not notice this blind spot since rapid movements of the eye and processing in the brain compensate for this absent information. This is the area that the ophthalmologist studies when evaluating a patient for glaucoma, a condition where the optic nerve becomes damaged often due to high pressure within the eye. As it looks like a cupwhen viewed with an ophthalmoscope, it is sometimes referred to as the Optic Cup.
Optic Nerve
The optic nerve is the structure which takes the information from the retina as electrical signals and delivers it to the brain where this information is interpreted as a visual image. The optic nerve consists of a bundle of about one million nerve fibers.
Retina
The membrane lining the back of the eye that contains photoreceptor cells. These
photoreceptor nerve cells react to the presence and intensity of light by sending an impulse to the brain via the optic nerve. In the brain, the multitude of nerve impulses received from the photoreceptor cells in the retina are assimilated into an image.
Sclera
The white, tough wall of the eye. Few diseases affect this layer. It is covered by the episclera (a fibrous layer between the conjunctiva and sclera ) and conjunctiva, and eye muscles are connected to this.
Vitreous
Next in our voyage through the eye is the vitreous. This is a jelly-like substance that fills the body of the eye. It is normally clear. In early life, it is firmly attached to the retina behind it.With age, the vitreous becomes more water-like and may detach from the retina. Often, little clumps or strands of the jelly form and cast shadows which are perceived as "floaters". While frequently benign, sometimes floaters can be a sign of a more serious condition such as a retinal tear or detachment and should be investigated with a thorough ophthalmologic
examination.
Nutrition and the eye
Introduction
There has been a lot of interest in the role of nutrition and nutritional supplements, such as vitamin tablets, and their effect on vision. The main focus has been on how vitamins and minerals might affect age-related eye conditions such as age-related macular-degeneration (AMD) and cataracts.
This page explores these issues and looks at the importance of good nutrition and how the eye can be affected by it.
Importance of good nutrition
Good nutrition is very important for both your general and eye health. Good nutrition helps our body to grow, repair wear and tear, protect against infection and to function properly.
An eye condition called 'xerophthalmia', which is a common cause of childhood blindness in developing countries, is a good example of how nutrition and eye health go hand in hand. This condition is caused by a lack of vitamin A in a person's diet and could be prevented by eating fresh vegetables, fat (animal and plant) and protein (eg meat, eggs, cheese, fish, poultry, milk, yoghurt, dairy products, nuts, seeds, pulses and grains).
There are many books on nutrition and eating a balanced diet. This topic will only be looked at briefly here. For further information on nutrition and healthy eating contact the British Nutrition Foundation (BNF).
Nutrition for the eye
Vitamins and the eye.
In various studies and clinical trials antioxidant vitamins found in certain foods have been linked with eye health. They help to maintain healthy cells and tissues in the eye.
The main focus has been on the anti-oxidant vitamins A, C and E. These vitamins can be found in many different sources of fruit and vegetables such as:
•oranges
•kiwis
•grapefruit
•dried apricots
•tomatoes
•peppers
•raw carrots
•green leafy vegetables including kale and spinach
•green peas
•green beans
•brussel sprouts.
They can also be found in nuts, seeds, dairy products and eggs.
These are only a few of the food types in which antioxidant vitamins can be found. The British Nutrition Foundation can provide you with further information on this.
Lutein and eye health.
More recently it has been suggested that two types of antioxidants, known as 'carotenoids', called Lutein (pronounced Loo-teen) and Zeaxanthin (pronounced Zay-a-za-thin) may also help with eye health. Some studies have found that people who have a good diet rich in carotenoids, particularly lutein and zeaxanthin, have a lower risk of developing AMD.
Lutein and Zeaxanthin can be found naturally in vegetables and fruit. For example, Lutein can be found in yellow peppers, mango, bilberries, and green leafy vegetables such as kale, spinach, chard and broccoli.
Zeaxanthin can be found in orange sweet peppers, broccoli, corn, lettuce (not iceberg), spinach, tangerines, oranges and eggs.
Many of these overlap with food types in which vitamins A, E and C are present.
Vitamins supplements and diet
Age-related macular degeneration (AMD)
A large research trial, called the 'Age-Related Eye Disease Study' (AREDS), showed that high quantities of the antioxidant vitamins A, C, E, beta-carotene and the minerals zinc as zinc oxide, and copper as cupric oxide, can help to slow down the progression of AMD.
It would be very hard to obtain the large quantity of vitamins used in the trial from your diet. Therefore some people who have AMD may consider supplementation with vitamins and anti-oxidants. Such high dosages of vitamins and minerals might have possible side effects on the body.
For this reason it is very important to consult your doctor first before taking a supplement.
Eye health
Following the AREDS research trial there have been over 150 smaller scale studies looking at how vitamins and minerals, both from food and in a vitamin supplement, can help eye health in general, and in particular AMD and cataracts. A number of these studies have looked specifically at the carotenoids Lutein and Zeaxanthin which have been particularly associated with healthy eyes.
Some of these studies have shown how certain vitamin and mineral supplements can have a positive effect on eyes and sight. Others have shown there to be no or little benefit. For this reason various organisations are calling for further, larger scale research.
As a result of these studies there are now a number of different supplements for eye health on the market. There is still divided medical opinion on the use of supplements for both eye health and for preventing, or slowing down, the progression of AMD and cataracts in particular.
The general consensus of opinion is that with a good balanced diet that includes sufficient fresh fruits and vegetables there should be no need to use supplements.
However, research has shown that many people in the UK do not get enough vitamins and minerals from their diet. Some people might consider taking a supplement for their general and eye health when:
•their diet does not include enough fresh fruit and vegetables
•diet does not include enough vitamins and minerals
•vitamins and minerals from food are not adequately absorbed by the body
•it is hard to obtain or prepare fresh fruit and vegetables
•they have been told to take a supplement by their doctor or nutritionist.
However, experts agree that taking supplements is not a substitute for a healthy diet.
Conclusion
Evidence regarding the benefits of nutritional supplements against eye disease is conflicting and there is no real agreement among researchers on this subject at present.
However, a consensus has been reached on the importance of a healthy, balanced diet full of fresh fruits and vegetables, particularly leafy green vegetables such as kale and spinach.
Key points to remember:
•eat a good, balanced diet with lots of fresh fruit and vegetables
•discuss changing your diet or taking vitamin supplements with your GP
•discuss your diet or taking a vitamin supplement with your GP if you believe that your diet may be inadequate
•the biggest avoidable risk is smoking
•protect your eyes from sunlight. Use good quality sunglasses, ie those that have the 'CE' mark, which means they meet the European Union Quality Standards. Wearing a brimmed hat also offers very good protection
•get your eyes tested at least every two years and more frequently if necessary.
There has been a lot of interest in the role of nutrition and nutritional supplements, such as vitamin tablets, and their effect on vision. The main focus has been on how vitamins and minerals might affect age-related eye conditions such as age-related macular-degeneration (AMD) and cataracts.
This page explores these issues and looks at the importance of good nutrition and how the eye can be affected by it.
Importance of good nutrition
Good nutrition is very important for both your general and eye health. Good nutrition helps our body to grow, repair wear and tear, protect against infection and to function properly.
An eye condition called 'xerophthalmia', which is a common cause of childhood blindness in developing countries, is a good example of how nutrition and eye health go hand in hand. This condition is caused by a lack of vitamin A in a person's diet and could be prevented by eating fresh vegetables, fat (animal and plant) and protein (eg meat, eggs, cheese, fish, poultry, milk, yoghurt, dairy products, nuts, seeds, pulses and grains).
There are many books on nutrition and eating a balanced diet. This topic will only be looked at briefly here. For further information on nutrition and healthy eating contact the British Nutrition Foundation (BNF).
Nutrition for the eye
Vitamins and the eye.
In various studies and clinical trials antioxidant vitamins found in certain foods have been linked with eye health. They help to maintain healthy cells and tissues in the eye.
The main focus has been on the anti-oxidant vitamins A, C and E. These vitamins can be found in many different sources of fruit and vegetables such as:
•oranges
•kiwis
•grapefruit
•dried apricots
•tomatoes
•peppers
•raw carrots
•green leafy vegetables including kale and spinach
•green peas
•green beans
•brussel sprouts.
They can also be found in nuts, seeds, dairy products and eggs.
These are only a few of the food types in which antioxidant vitamins can be found. The British Nutrition Foundation can provide you with further information on this.
Lutein and eye health.
More recently it has been suggested that two types of antioxidants, known as 'carotenoids', called Lutein (pronounced Loo-teen) and Zeaxanthin (pronounced Zay-a-za-thin) may also help with eye health. Some studies have found that people who have a good diet rich in carotenoids, particularly lutein and zeaxanthin, have a lower risk of developing AMD.
Lutein and Zeaxanthin can be found naturally in vegetables and fruit. For example, Lutein can be found in yellow peppers, mango, bilberries, and green leafy vegetables such as kale, spinach, chard and broccoli.
Zeaxanthin can be found in orange sweet peppers, broccoli, corn, lettuce (not iceberg), spinach, tangerines, oranges and eggs.
Many of these overlap with food types in which vitamins A, E and C are present.
Vitamins supplements and diet
Age-related macular degeneration (AMD)
A large research trial, called the 'Age-Related Eye Disease Study' (AREDS), showed that high quantities of the antioxidant vitamins A, C, E, beta-carotene and the minerals zinc as zinc oxide, and copper as cupric oxide, can help to slow down the progression of AMD.
It would be very hard to obtain the large quantity of vitamins used in the trial from your diet. Therefore some people who have AMD may consider supplementation with vitamins and anti-oxidants. Such high dosages of vitamins and minerals might have possible side effects on the body.
For this reason it is very important to consult your doctor first before taking a supplement.
Eye health
Following the AREDS research trial there have been over 150 smaller scale studies looking at how vitamins and minerals, both from food and in a vitamin supplement, can help eye health in general, and in particular AMD and cataracts. A number of these studies have looked specifically at the carotenoids Lutein and Zeaxanthin which have been particularly associated with healthy eyes.
Some of these studies have shown how certain vitamin and mineral supplements can have a positive effect on eyes and sight. Others have shown there to be no or little benefit. For this reason various organisations are calling for further, larger scale research.
As a result of these studies there are now a number of different supplements for eye health on the market. There is still divided medical opinion on the use of supplements for both eye health and for preventing, or slowing down, the progression of AMD and cataracts in particular.
The general consensus of opinion is that with a good balanced diet that includes sufficient fresh fruits and vegetables there should be no need to use supplements.
However, research has shown that many people in the UK do not get enough vitamins and minerals from their diet. Some people might consider taking a supplement for their general and eye health when:
•their diet does not include enough fresh fruit and vegetables
•diet does not include enough vitamins and minerals
•vitamins and minerals from food are not adequately absorbed by the body
•it is hard to obtain or prepare fresh fruit and vegetables
•they have been told to take a supplement by their doctor or nutritionist.
However, experts agree that taking supplements is not a substitute for a healthy diet.
Conclusion
Evidence regarding the benefits of nutritional supplements against eye disease is conflicting and there is no real agreement among researchers on this subject at present.
However, a consensus has been reached on the importance of a healthy, balanced diet full of fresh fruits and vegetables, particularly leafy green vegetables such as kale and spinach.
Key points to remember:
•eat a good, balanced diet with lots of fresh fruit and vegetables
•discuss changing your diet or taking vitamin supplements with your GP
•discuss your diet or taking a vitamin supplement with your GP if you believe that your diet may be inadequate
•the biggest avoidable risk is smoking
•protect your eyes from sunlight. Use good quality sunglasses, ie those that have the 'CE' mark, which means they meet the European Union Quality Standards. Wearing a brimmed hat also offers very good protection
•get your eyes tested at least every two years and more frequently if necessary.
Eye Problems & Children
Eye problems are common in children, and range from infections, irritation, allergies to changes in vision. Any injury to the eye or problem that is affecting your child's vision should be evaluated by a doctor right away.
Conjunctivitis: conjunctivitis or pinkeye, is an infection caused by a virus or bacteria, that can cause redness in one or both eyes and a watery discharge. Bacterial conjunctivitis causes a red eye and matting of the eyes with a green or yellow discharge and it requires treatment with antibiotics (usually a topical ointment or drops). Conjunctivitis caused by a virus can also produce a red eye, but the discharge is usually just watery or cloudy. This type of infection is usually accompanied by symptoms of an upper respiratory tract infection, such as a runny nose and cough, and he may have an enlarged lymph gland in front of his ear. No treatment is usually required for this type of infection.
Allergic Conjunctivitis: conjunctivitis can also be caused by allergies, especially in children with allergies or asthma, and can cause both eyes to be red and swollen, itching and tearing. Antihistamines or eye drops may be needed for treatment.
Stye: A stye or hordeolum produces a tender, red swollen area on your child's eyelid. It may point inward or it may be on the outside of the eyelid margin. Treatment is with warm compresses and sometimes topical antibiotics.
Chalazion: If there is a nodule or swollen area on the eyelid, but it isn't red or tender, then it is probably a chalazion, which is an inflamed meibomian gland that improves by using warm compresses several times each day for several weeks or months. Persistent cases sometimes require excision.
Corneal Abrasion: can occur after having a foreign body in the eye or after scratching the eye. This causes pain, tearing, and sensitivity to light. An abrasion can be detected by your pediatrician by putting fluorescein dye drops in the eye and looking at it with a special blue light. Treatment is with antibiotic ointment until the abrasion has healed, unless the abrasion is over the pupil, in which case your child should probably see an ophthalmologist.
Blepharitis: an inflammation of the eyelids that causes them to have redness, crusting and scaling and the eyes may be itchy or irritated. Treatment is usually with daily cleansing of the eyelids with a no-tears shampoo and a soft cloth. Sometimes an antibiotic cream is also needed. Untreated, this can lead to the formation of a stye or chalazion.
Foreign body: having a foreign object in the eye, such as a piece of sand, etc, can cause pain,, especially with blinking, and tearing. Older children may complain that it feels like there is something in the eye. Treatment is by washing the object out of the eye with lukewarm water. See you pediatrician if that doesn't help.
Dacryostenosis: This is a blocked tear duct, are very common in newborns and infants and usually clear up on their own by the time your baby is a year old. It can cause some matting of the eye, and persistent tearing in one or both eyes. You should wipe away any discharge with a warm cloth. You can also gently massage the side of the upper part of your baby's nose to try and open up the duct. If your baby has a lot of discharge that needs to be wiped away more than a few times a day, then he may need an antibiotic and you should see your doctor.
Subconjunctival hemorrhages: occur because of pressure during the birth process. It causes a red streaking or red spots of blood on the white part of the eye and it will go away in a few weeks. It can also occur in older children after vomiting forcibly.
Periorbital cellulitis: This is a serious infection that can cause a fever and your child's eyelids to be red, swollen and tender. Left untreated, it can progress to orbital cellulitis or a deep infection of the eye, which can cause the eye to be pushed outwards (proptosis), and may limit the movement of the eye. You should seek medical attention immediately for either of these conditions.
Other eye problems include those caused by trauma, including fractures to the bones around the eye, chemical burns, and lacerations or cuts to the eye or eyelids. These require immediate medical attention.
Conjunctivitis: conjunctivitis or pinkeye, is an infection caused by a virus or bacteria, that can cause redness in one or both eyes and a watery discharge. Bacterial conjunctivitis causes a red eye and matting of the eyes with a green or yellow discharge and it requires treatment with antibiotics (usually a topical ointment or drops). Conjunctivitis caused by a virus can also produce a red eye, but the discharge is usually just watery or cloudy. This type of infection is usually accompanied by symptoms of an upper respiratory tract infection, such as a runny nose and cough, and he may have an enlarged lymph gland in front of his ear. No treatment is usually required for this type of infection.
Allergic Conjunctivitis: conjunctivitis can also be caused by allergies, especially in children with allergies or asthma, and can cause both eyes to be red and swollen, itching and tearing. Antihistamines or eye drops may be needed for treatment.
Stye: A stye or hordeolum produces a tender, red swollen area on your child's eyelid. It may point inward or it may be on the outside of the eyelid margin. Treatment is with warm compresses and sometimes topical antibiotics.
Chalazion: If there is a nodule or swollen area on the eyelid, but it isn't red or tender, then it is probably a chalazion, which is an inflamed meibomian gland that improves by using warm compresses several times each day for several weeks or months. Persistent cases sometimes require excision.
Corneal Abrasion: can occur after having a foreign body in the eye or after scratching the eye. This causes pain, tearing, and sensitivity to light. An abrasion can be detected by your pediatrician by putting fluorescein dye drops in the eye and looking at it with a special blue light. Treatment is with antibiotic ointment until the abrasion has healed, unless the abrasion is over the pupil, in which case your child should probably see an ophthalmologist.
Blepharitis: an inflammation of the eyelids that causes them to have redness, crusting and scaling and the eyes may be itchy or irritated. Treatment is usually with daily cleansing of the eyelids with a no-tears shampoo and a soft cloth. Sometimes an antibiotic cream is also needed. Untreated, this can lead to the formation of a stye or chalazion.
Foreign body: having a foreign object in the eye, such as a piece of sand, etc, can cause pain,, especially with blinking, and tearing. Older children may complain that it feels like there is something in the eye. Treatment is by washing the object out of the eye with lukewarm water. See you pediatrician if that doesn't help.
Dacryostenosis: This is a blocked tear duct, are very common in newborns and infants and usually clear up on their own by the time your baby is a year old. It can cause some matting of the eye, and persistent tearing in one or both eyes. You should wipe away any discharge with a warm cloth. You can also gently massage the side of the upper part of your baby's nose to try and open up the duct. If your baby has a lot of discharge that needs to be wiped away more than a few times a day, then he may need an antibiotic and you should see your doctor.
Subconjunctival hemorrhages: occur because of pressure during the birth process. It causes a red streaking or red spots of blood on the white part of the eye and it will go away in a few weeks. It can also occur in older children after vomiting forcibly.
Periorbital cellulitis: This is a serious infection that can cause a fever and your child's eyelids to be red, swollen and tender. Left untreated, it can progress to orbital cellulitis or a deep infection of the eye, which can cause the eye to be pushed outwards (proptosis), and may limit the movement of the eye. You should seek medical attention immediately for either of these conditions.
Other eye problems include those caused by trauma, including fractures to the bones around the eye, chemical burns, and lacerations or cuts to the eye or eyelids. These require immediate medical attention.
Basic functions of the human eye
The basic function of the human eye is to see. Other functions involving the accessory structures and secretions of the eye prevent foreign particles from injuring the ocular organ and pathogens from entering the body through this route.
In its simplest definition, sight is the transmission of light signals through nerve endings to the brain, which interprets the signals and produces visions of what is seen. The light reaches the nerve endings by traveling through the eye, making the brain's interpretation dependent on the accuracy of the path the light waves travel through the structures of the eye.
Human TissueHuge Selection. Great value 4 less! Many Species, 5000+ Tissue Types.www.BioChain.comHuman BrainAnswers to your questions on Alzheimer's Disease and more.yourtotalhealth.ivillage.comAdvanced BioMatrix, Inc.PureCol Purified Collagen Products 3D Matrix Cell Culture Reagentswww.advancedbiomatrix.comLight's
Path Through the Eye
Light enters the eye first through the cornea, a thin clear sheath covering the outer, visible portion of the eye. There are no blood vessels in the cornea because it must remain clear for light waves to pass through uninterrupted. Under the cornea is a cavity containing a nutrient-filled liquid, aqueous humor, which provides nutrients to the cornea and lens. The pupil is the opening that controls how much light passes from the cornea to the lens. The iris, the colored portion of the eye, is actually two sets of muscle fibers that control the size of the pupil.
The lens is the refraction system of the eye; it is located on the other side of the aqueous humor cavity. The lens also contains no blood vessels so that light can pass through unhindered. Light is refracted and focused onto the back of the eye where the nerve endings are present; what is seen may be out of focus if the lens is misshapen or the wrong thickness, resulting in the vision disorders near-sightedness, far-sightedness, and stigmatism. The lens is adjusted by muscles called the ciliary body, which allow light to be focused for distance and movement.
Light travels from the lens through a chamber filled with vitreous humor, a semi-solid that helps the eye keep its shape. The vitreous humor is also what holds the retina in place. The retina is the back of the inside of the eye and contains light receptors. The receptors are nerve endings with a direct link to the brain via the optic nerve. Alterations in the vitreal pressure due to eye injuries or diabetes can affect vision and cause retinal detachment or blindness.
Light Receptors How Vision Works
Receptors in the eye consist of rods and cones. Rods detect light regardless of wavelength and help the brain determine light intensity, whether it is bright or dim. Cones are only active in bright light and are particular to red, blue, or green. Each type of cone detects a particular light wavelength. Color blindness is a disorder that occurs when a person lacks a particular type or types of cones, allowing only bright, dim, and the remaining wavelengths to be seen.
There is a blind spot at the back of the eye at the point where the optic nerve passes through the eyeball and there are no receptors. With two working eyes, the blind spot is compensated for by binocular vision. There is also a spot in the retina with the greatest concentration of cones, called the macula fovea. This specialized pit in the 5-mm wide macula is important for high visual acuity. The macula has two layers of ganglion cells, the nerve endings communicating with the brain via the optic nerve.
Other Functions of the Eye
The eye has accessory structures. The eyelids have hairs called eyelashes that protect the eye and keep out dust and harmful debris. Scratching the cornea would prevent light from passing through properly and hinder vision. Tear ducts, called lacrimal glands, secrete a salt solution to keep the eye from drying out as well as a lysozyme that protects the eye from bacteria
In its simplest definition, sight is the transmission of light signals through nerve endings to the brain, which interprets the signals and produces visions of what is seen. The light reaches the nerve endings by traveling through the eye, making the brain's interpretation dependent on the accuracy of the path the light waves travel through the structures of the eye.
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Path Through the Eye
Light enters the eye first through the cornea, a thin clear sheath covering the outer, visible portion of the eye. There are no blood vessels in the cornea because it must remain clear for light waves to pass through uninterrupted. Under the cornea is a cavity containing a nutrient-filled liquid, aqueous humor, which provides nutrients to the cornea and lens. The pupil is the opening that controls how much light passes from the cornea to the lens. The iris, the colored portion of the eye, is actually two sets of muscle fibers that control the size of the pupil.
The lens is the refraction system of the eye; it is located on the other side of the aqueous humor cavity. The lens also contains no blood vessels so that light can pass through unhindered. Light is refracted and focused onto the back of the eye where the nerve endings are present; what is seen may be out of focus if the lens is misshapen or the wrong thickness, resulting in the vision disorders near-sightedness, far-sightedness, and stigmatism. The lens is adjusted by muscles called the ciliary body, which allow light to be focused for distance and movement.
Light travels from the lens through a chamber filled with vitreous humor, a semi-solid that helps the eye keep its shape. The vitreous humor is also what holds the retina in place. The retina is the back of the inside of the eye and contains light receptors. The receptors are nerve endings with a direct link to the brain via the optic nerve. Alterations in the vitreal pressure due to eye injuries or diabetes can affect vision and cause retinal detachment or blindness.
Light Receptors How Vision Works
Receptors in the eye consist of rods and cones. Rods detect light regardless of wavelength and help the brain determine light intensity, whether it is bright or dim. Cones are only active in bright light and are particular to red, blue, or green. Each type of cone detects a particular light wavelength. Color blindness is a disorder that occurs when a person lacks a particular type or types of cones, allowing only bright, dim, and the remaining wavelengths to be seen.
There is a blind spot at the back of the eye at the point where the optic nerve passes through the eyeball and there are no receptors. With two working eyes, the blind spot is compensated for by binocular vision. There is also a spot in the retina with the greatest concentration of cones, called the macula fovea. This specialized pit in the 5-mm wide macula is important for high visual acuity. The macula has two layers of ganglion cells, the nerve endings communicating with the brain via the optic nerve.
Other Functions of the Eye
The eye has accessory structures. The eyelids have hairs called eyelashes that protect the eye and keep out dust and harmful debris. Scratching the cornea would prevent light from passing through properly and hinder vision. Tear ducts, called lacrimal glands, secrete a salt solution to keep the eye from drying out as well as a lysozyme that protects the eye from bacteria
Common Eye Problems
Most of us will experience temporary eye problems from time to time, including itching, blurriness or fatigue. Most of these conditions are short-lived and will probably go away on their own with no complications. However, sudden eye problems and those that last for more than a couple of days should be checked by an eye doctor. The following is a list of common eye problems and their possible causes.
Eye twitching:
While usually harmless, an eye twitch can be very annoying. Twitching may be associated with the following:
•Stress
•Caffeine
•Fatigue
•Pink eye
•Panic disorder
•Tourette syndrome
Itchy eyes:
Are your eyes itching? Itchy, red eyes can be very uncomfortable. Here are a few conditions that may cause itchy eyes:
•Pink eye
•Blepharitis
•Dry eye syndrome
•Allergies
Tired eyes:
Do your eyes feel tired and fatigued? The following conditions may cause tired eyes:
•Dry eye syndrome
•Computer vision syndrome
•Farsightedness
•Astigmatism
Seeing floaters:
Do you see spots in your vision? Do you see faint strands floating around that seem to move away if you look at them? Floaters may occur with the following conditions:
•Retinal detachment
•Diabetic retinopathy
•Posterior vitreous detachment
•Stroke
Blurry vision:
Blurry vision, or the inability to bring objects into sharp focus, can be caused by a number of conditions. Sometimes fatigue or illness can cause vision to be temporarily blurred. The following eye problems can also cause blurry vision:
•Nearsightedness
•Farsightedness
•Presbyopia
•Astigmatism
•Cataracts
•Glaucoma
•Uveitis
•Dry eye syndrome
•Migraine
Age-related problems:
Many eye problems occur as we get older. As always, annual comprehensive eye examinations are important for maintaining healthy vision as we age. The following eye problems may develop due to aging:
•Age-related macular degeneration
•Presbyopia
•Cataracts
•Glaucoma
•Posterior vitreous detachment
Children's eye problems:
Parents are often the first to notice eye problems in their children. Alert an eye care professional if you notice possible problems with your child's eyes or vision. The following eye problems may be responsible:
•Lazy eye
•Strabismus
•Color blindness
•Pink eye
•Farsightedness
Eye twitching:
While usually harmless, an eye twitch can be very annoying. Twitching may be associated with the following:
•Stress
•Caffeine
•Fatigue
•Pink eye
•Panic disorder
•Tourette syndrome
Itchy eyes:
Are your eyes itching? Itchy, red eyes can be very uncomfortable. Here are a few conditions that may cause itchy eyes:
•Pink eye
•Blepharitis
•Dry eye syndrome
•Allergies
Tired eyes:
Do your eyes feel tired and fatigued? The following conditions may cause tired eyes:
•Dry eye syndrome
•Computer vision syndrome
•Farsightedness
•Astigmatism
Seeing floaters:
Do you see spots in your vision? Do you see faint strands floating around that seem to move away if you look at them? Floaters may occur with the following conditions:
•Retinal detachment
•Diabetic retinopathy
•Posterior vitreous detachment
•Stroke
Blurry vision:
Blurry vision, or the inability to bring objects into sharp focus, can be caused by a number of conditions. Sometimes fatigue or illness can cause vision to be temporarily blurred. The following eye problems can also cause blurry vision:
•Nearsightedness
•Farsightedness
•Presbyopia
•Astigmatism
•Cataracts
•Glaucoma
•Uveitis
•Dry eye syndrome
•Migraine
Age-related problems:
Many eye problems occur as we get older. As always, annual comprehensive eye examinations are important for maintaining healthy vision as we age. The following eye problems may develop due to aging:
•Age-related macular degeneration
•Presbyopia
•Cataracts
•Glaucoma
•Posterior vitreous detachment
Children's eye problems:
Parents are often the first to notice eye problems in their children. Alert an eye care professional if you notice possible problems with your child's eyes or vision. The following eye problems may be responsible:
•Lazy eye
•Strabismus
•Color blindness
•Pink eye
•Farsightedness
Eye Health Is Important Throughout Our Lives
Keeping our eyes healthy is important throughout our lives. Learn how to protect your vision, prevent and treat eye diseases, and prevent eye injuries. Find out all about the different eye care professionals. Along with eye examinations, there are many things you can do to keep your eyes healthy.
Protecting Your Vision
Eye Injuries
Eye Diseases
Eye Problems
Protecting Your Vision
Eye Injuries
Eye Diseases
Eye Problems
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