Disorders and Diseases
Several diseases affect the eye, either directly or as part of a system-wide problem. Often serious, these conditions require immediate professional care to preserve your vision.
There are several factors that can cause the eyes to bulge. However, swelling of the muscles, fat, and tissue behind the eyes-which makes the eyes themselves protrude-is often a symptom of Graves’ Disease, which is caused by an overproduction of the hormone thyroxin. In severe cases, Graves’ Disease may also cause double vision.
Because bulging eyes are exposed to more air, it is difficult to keep them lubricated. When Graves’ Disease is mild, the chief thing you need to do is soothe your eyes. You might try artificial tears. In more severe cases, prescription drugs or radioactive iodine can slow thyroxin production.
You may have CMV Retinitis if you have AIDS or another immune disorder and you see.
Floating spots Flashing lights Blind spots or blurred vision
CMV Retinitis is a serious infection of the retina that affects nearly half of people with AIDS (Acquired Immune Deficiency Syndrome) and that may also affect people with other immune disorders. Most infections happen when a person’s T cell count drops below 40.
There are several medications that minimize or eliminate CMV Retinitis. There are also some oral drugs that slow CMV infections. The earlier you begin treatment, the more your vision can be helped. And, if only one eye is infected, taking any of these medications may protect the other eye.
Color blindness is not actually blindness in the true sense-people who are affected by it simply do not agree with most other people about color matching. Most people affected by color blindness cannot distinguish between reds and greens in dim light; some cannot separate blues from yellows; and a very small group have a condition called monochromatism which only allows them to see black and white.
Color blindness is caused by a lack of one or more of the light-sensitive substances found in the retina and is the result of a recessive gene on the X chromosome. Color blindness of various kinds affects about 7% of men-and less than 1% of women.
There is no known method of correcting color blindness. However, the vision of most color-blind people is normal in all other respects.
Strabismus is a general term for eyes that are misaligned and point in different directions. Typically this is seen as crossed-eyes and is almost always accompanied by lazy eye (amblyopia). Your child may have strabismus if
- Their eyes are crossed or wall eyed
- Their eyes do not move together
- The point of light reflected in each eye is not symmetrical
- They tend to tilt their head to one side
- They are unable to gauge depth
- They squint into the sun with only one eye
No one knows why some children’s eyes are misaligned, although it does seem to run in families. Because misaligned eyes don’t focus together, double vision occurs. A young child with strabismus will unconsciously ignore one of the two images they see-and the related nerve connections between their eye and brain will fail to develop. This brings about lazy eye (amblyopia).
DIABETIC MACULAR EDEMA
Diabetes is the most common cause of blindness among working-aged people, and all people living with the disease should monitor their eye health carefully. Over time, diabetes can lead to diabetic retinopathy, which is damage to the blood vessels in the retina. As this damage continues, blood vessels in the retina begin to leak fluid.
This, in turn, can lead to a condition known as diabetic macular edema, or DME, where fluid accumulates in the macula. Patients with DME typically experience blurred vision which may progress to blindness.
- Diabetic Macular Edema (DME) affects up to 10% of all patients with diabetes1:-
- Up to 75,000 new cases occur every year1
- Up to 30% of patients with DME will experience moderate visual loss (doubling of the visual angle)1
There are two kinds of DME:
- Focal DME is caused by tiny abnormalities in blood vessels, known as microaneurysms. These leaking microaneurysms can lead to vision loss.
- Diffuse DME is caused by widening (dilation) of retinal capillaries (extremely thin, narrow blood vessels) throughout the back of the eye.
All patients who suffer from diabetes have a risk of developing DME. The symptoms of DME can include:-
- Blurred vision.
- Double vision
- Floaters (small black dots or lines made up of cellular debris seen “floating” across the front of the eye) These floaters may temporarily interfere with vision. They are also linked with other eye diseases.
DME is linked with the following:-
- The degree of diabetic retinopathy (problems with blood vessels in the retina related to diabetes)
- The length of time a patient has had diabetes
- The type of diabetes each patient has (the milder the diabetes, the lower the incidence of DME)
- Severe hypertension (high blood pressure) Fluid retention
- Hypoalbuminemia (low protein in body fluids)
- Hyperlipidemia (high levels of fats in the blood)
Many of these conditions can make DME worse, but when they are treated and controlled, DME may get better
- Laser treatment for focal DME
- Laser treatment for diffuse DME
- Laser treatment for diffuse DME
Diabetic retinopathy is never painful-and in fact, you may not have any symptoms at all. Occasionally, if there is fluid retention, your vision might gradually become blurred, and if there is bleeding, your vision might be spotty.
If you have diabetes, you are in danger of having elevated blood sugar, which can damage the blood vessels in your eyes, potentially leading to diabetic retinopathy. The damaged blood vessels may leak fluid or bleed, causing the retina to swell, and your vision to become blurred. As the disease progresses, new, fragile blood vessels grow on the surface of the retina. These vessels may break, releasing blood into the vitreous. They may also pull the retina away from the back of the eye. In addition, abnormal blood vessels can grow on the iris, causing glaucoma.
Take good care of yourself-by maintaining a healthy diet and exercising regularly-to significantly reduce your risk of diabetic eye disease. And get regular eye exams to catch the disease in its early stages, facilitating treatment and preventing complications. Serious cases of diabetic retinopathy can be treated surgically.
FLASHES AND FLOATERS
Flashes are akin to the stars you may see if you have a blow to the eye area. Floaters are small specks or clouds that move across your field of vision-especially when you are looking at a plain background, like a blank wall or a cloudless blue sky
With age, your vitreous gel may shrink, forming tiny clumps inside your eye. As the shrinking occurs, tugging on the retina, the nerve layer at the back of the eye can cause flashes. Floaters are simply the shadows cast on the retina by the resulting clumps.
Correcting flashers and floaters:
Looking up and down may move the floaters out of the way. While some floaters may remain in your vision, many of them will fade over time and become less bothersome. However, if you begin seeing new flashes and floaters you should schedule an eye exam immediately to find out whether your retina has been torn, or if there is another problem that requires medical attention.
Sometimes the cornea in the front of the eye, which normally is round, becomes thin and cone shaped. Like nearsightedness or astigmatism this abnormal shape prevents light from focusing correctly on the retina.
In its earliest stages-which often appear in the late teens or twenties- keratoconus causes slightly blurred vision and increased sensitivity to bright lights. As the disease progresses over ten or 20 years, vision may become more and more distorted.
In the early stages, eyeglasses or soft contact lenses can correct the visual distortion. Later, as the disorder progresses, GP (gas permeable) contact lenses may be preferable.
Commonly known as lazy eye, amblyopia is poor vision in an eye that does not receive adequate use during early childhood.
Amblyopia is often a consequence of one of the eyes not being used, from either crossed eyes (strabismus) or ptosis, which is a drooping of the upper eyelid. It may also be caused by one eye simply having better vision and a child relying on it more heavily.
With early diagnosis and treatment, the sight in the lazy eye can be restored. However, left untreated, the eye may become functionally blind. Treatments include:-
- Patching or covering the better-seeing eye
- Eye drops or ointments
- Contact Lenses
Whenever ordinary glasses or contact lenses don’t produce clear vision, you are considered to have low vision.
The most common cause for low vision is macular degeneration, a disease of the optic nerve. However, there are a wide variety of other causes, including:-
- Birth defects
- Inherited diseases
Correcting low vision:
Currently, low vision cannot be corrected. However, there are a wide array of devices to help people with low vision, including large print reading materials, high-contrast watches, and machines that talk. Magnifying devices that facilitate daily activities are also available.
Age-related macular degeneration (AMD) is the leading cause of legal blindness in people over age 55. It affects over 10 million adults in the U.S. alone. AMD is the physical disturbance of the center of the retina called the macula. Roughly the size of the capital letter “O” in this sentence, the macula is the part of the retina that provides our most acute and detailed vision for reading, driving, and performing other activities that require fine, sharp, straight-ahead vision.
There are two types of macular degeneration:-
- Dry macular degeneration – Affects about 90% of those with the disease. Small yellow deposits, known as “drusen” accumulate underneath the macula. These drusen may cause the important vision cells to slowly break down. With less of the macula working, you may start to lose central vision in the affected eye as the years go by.
- Wet macular degeneration – While occurring in only 10% of all people with AMD, it actually accounts for 90% of all severe vision loss from the disease. It occurs when new blood vessels start to grow into places in the macula where they should not be. This causes rapid damage to the macula that can lead to the loss of central vision in a short period of time.
In the early stages of AMD, the patient may not experience any symptoms. An eye doctor usually notices the first indicator of this disease during a routine visit. A dilated eye exam can detect small yellow deposits, known as “drusen”, located in and under the macula, or the presence of abnormal blood vessels. If drusen are found, it is often the first physical sign that macular degeneration may have developed. As drusen accumulate, the cells that transport nutrients into the retina are lifted further and further away from their blood supply, impairing the transport of vital substances to the macular area of the retina. This can lead to distortion and deterioration of vision. Since macular degeneration is often part of the natural aging process, people experience different symptoms. For many it is hardly noticeable, others may notice:
- Blurred vision
- A dark or empty area in the central area of vision
- Visual distortion of straight lines
Correcting macular degeneration:
In its early stages, wet macular degeneration can be treated with laser surgery. Currently there is no treatment for dry macular degeneration. Since peripheral vision is not affected, people can continue many of their favorite activities using low-vision optical devices such as magnifying glasses.In a recent important study, people at high risk for advanced AMD lowered their risk by about 25%. They were treated with a high dose combination of vitamin C, vitamin E, beta-carotene, and zinc.
Surgery for wet macular degeneration is a brief and usually painless outpatient procedure. The doctor uses highly focused laser beams to seal the leaking blood vessels. In most cases, the procedure preserves overall sight, although a small, permanently dark spot is left where the laser makes contact, leaving vision slightly impaired. Bausch & Lomb has a number of precision instruments used for this surgery.
Ocular hypertension is an increase in pressure in the eye that is above the range considered normal, usually greater than 21mm Hg. It is distinguished from glaucoma, a more serious eye condition, in that there are no detectable changes in vision, no evidence of visual field loss, and no damage to the optic nerve. However, patients diagnosed with ocular hypertension have an increased risk of developing glaucoma
Most people experience no symptoms related to ocular hypertension. However, it is one of the easiest and most important diseases for your eye doctor to diagnose-and a key reason to have regular eye exams.
Correcting ocular hypertension:
There is no cure for ocular hypertension. Some eye care professionals may choose to treat with medication to lower the eye pressure. Since this eye condition may increase your risk of developing glaucoma, careful and frequent monitoring by your eye care professional is recommended to assess overall eye health.
When the retina detaches, people experience a painless change in or loss of vision. People sometimes liken it to a gray curtain moving across their field of vision. This change is often accompanied by sparks or flashing lights.
Sometimes-with age-the vitreous gel simply pulls away from the retina. Usually this does not cause a problem, but occasionally it tears the retina, allowing fluid to seep underneath and lift the retina up.
Correcting retinal detachment:
Retinal detachment can be treated quite successfully with surgery
Sometimes your eyelid simply twitches. It is rarely uncomfortable-but it can be irritating. Most of all, it can make you wonder if there is really something wrong. Generally, there isn’t.
Twitches in your eyelid are similar to those in your arm or leg. While no one really knows what causes them, they seem to be related to fatigue or stress. Occasionally insufficient lubrication may also play a role.
Correcting twitching tics:
Gently massaging the affected eyelid may help the muscle relax, and minimize the twitching. You may also want to use some eye drops in case dry eye is a contributing
Uveitis, the third leading cause of blindness in the U.S. after Diabetic Retinopathy and Macular Degeneration, is the inflammation of the inside the eye, specifically affecting one or more of the three parts of the eye that make up the uvea: the iris, the ciliary body and the choroid.
- Light sensitivity
- Blurring of vision
- Redness of the eye
Uveitis may be infectious – resulting from virus, fungus, parasites or bacteria. It can also be non-infectious – resulting from a trauma, an immunological process, or in many cases having no known etiology.
Eye and different types of uveitis:
The eye is a hollow, fluid-filled, ball-shaped organ. It has several layers. The outer layer is the tough coat composed of the cornea and sclera, the innermost is the retina, a thin light-receptor layer, and the middle layer is the uvea. The uvea is made up of iris, the ciliary body and the choroid. When any part of the uvea becomes inflammed then it is called uveitis.
- Anterior Uveitis – This is the most common form of uveitis, accounting for 75% of cases. It is often referred to as Iritis as the iris is the part of the uvea that is usually inflammed.
- Intermediate Uveitis – This affects the area just behind the ciliary body (parsplana) and also the most forward edge of the retina. This is the next most common type of uveitis.
- Posterior Uveitis – This is when the inflammation affects the part of the uvea at the back of the eye, the choroid. Often the retina is affected in this group. The choroid is basically a layer rich in small blood vessels, which nourishes the photoreceptor layer of the retina. This kind of uveitis is commonly slower in onset and may last longer, and it is often more difficult to treat and is often associated with progressive loss of vision.
Currently the following are used to treat uveitis:-
- Eye drops, especially steroids, to reduce inflammation and pain. Eye drops do not penetrate well to the back of the eye, therefore this type of treatment is not efficacious in posterior uveitis.
- Periocular injections of steroids. This is an uncomfortable form of therapy but can be very effective especially in acute episodes of uveitis. This effect is not long lasting (3-4 weeks).
- Systemic or oral administration of steroids, other immuno-suppressants or anti-metabolite drugs. These drugs have poor penetration into the eye and thus the systemic dose required to treat uveitis in the eye is frequently associated with side-effects in the rest of the body (including Cushing’s Syndrome, renal, liver and bone-marrow damage).