Select a letter from the alphabet below to find the Eye Disease or select "All" to view the entire list of diseases.

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N

Nearsightedness

Description:Also called myopia. A condition in which the length of the eye is too long, causing light rays to focus in front of the retina rather than on it, resulting in blurred distance vision. Additional symptoms include eyestrain, poor night vision and squinting.

Cause:This is caused by a cornea that is steeper, or an eye that is longer, than a normal eye. Nearsighted people typically see well up close, but have difficulty seeing far away.

Treatment:The treatment for nearsightedness depends on several factors such as the patient’s age, activities, and occupation. Vision can corrected with glasses, contacts, or surgery. Refractive procedures such as LASIK can be considered for adults when the prescription has remained stable for at least one year.

Nearsightedness

Description:Also called myopia. A condition in which the length of the eye is too long, causing light rays to focus in front of the retina rather than on it, resulting in blurred distance vision. Additional symptoms include eyestrain, poor night vision and squinting.

Cause:This is caused by a cornea that is steeper, or an eye that is longer, than a normal eye. Nearsighted people typically see well up close, but have difficulty seeing far away.

Treatment:The treatment for nearsightedness depends on several factors such as the patient’s age, activities, and occupation. Vision can corrected with glasses, contacts, or surgery. Refractive procedures such as LASIK can be considered for adults when the prescription has remained stable for at least one year.

Neovascular Glaucoma

Description:Neovascular glaucoma is an unusual type of closed-angle glaucoma which can be particularly difficult to treat. In many instances, it is first recognized when a patient notes a sudden loss of vision, a red and uncomfortable eye, or even pain.

Cause:This condition is considered to be a type of closed-angle glaucoma because the trabecular meshwork, the tiny drain through which aqueous humor (the clear fluid which nourishes the front of the eye) exits the eye, is closed or blocked. This results directly from the growth of new blood vessels (neovascularization), which are not normally present in this location. This is why the condition is known as neovascular glaucoma. As the blood vessels grow, they are first accompanied by an almost invisible fibrous tissue which is like a thin scar. This tissue blocks the drainage of the fluid through the trabecular meshwork. The fluid accumulates within the eye and causes the eye pressure to increase. If this happens over a short period of time, the patient may have sudden pain. If the blockage of the drain occurs more slowly, there may only be redness with some discomfort. In both situations, the eye pressure needs to be lowered if vision is to be saved.

Treatment:Eye pressure needs to be lowered immediately to prevent it from further damaging the optic nerve. Initially, this is done through use of medications that reduce the amount of aqueous humor which flows into the eye. Eye drops, particularly beta-blocking agents, and a pill, such as acetazolamide, are most effective in this regard. It is then necessary to treat the eye and eliminate the neovascularization. This is particularly important if the glaucoma is recognized early so that the drain is not completely blocked. The neovascularization is most effectively eliminated by destroying the structures which are poorly nourished as a result of the reduced blood flow. These structures are usually in the back of the eye in the retina. Destroying these structures eliminates the chemicals which stimulate the formation of new blood vessels in the front of the eye. The most effective way to treat the eye is using a laser beam which is focused through the eye to burn the retina. If the neovascularization persists, and even if it is no longer present, it may not be possible to lower the eye pressure sufficiently with eye drops and pills. In this case, it is necessary to reduce the eye pressure through surgery.

Night Blindness

Description:Night blindness, also called nyctalopia, is the inability or reduced ability to see in dim light or darkness. It also refers to the condition in which the time it takes for the eyes to adapt to darkness is prolonged.

Cause:Night blindness is due to a disorder of the cells in the retina that are responsible for vision in dim light. It has many causes, including nearsightedness, glaucoma, cataracts, retinitis pigmentosa, or vitamin A deficiency.

Treatment:Treatment for night blindness will depend upon its cause. Treatment may be as simple as a new prescription for your eyeglasses or switching glaucoma medications, or it may require surgery in cases of cataracts.

Nyctalopia

Description:Nyctalopia, also called night blindness, is the inability or reduced ability to see in dim light or darkness. It also refers to the condition in which the time it takes for the eyes to adapt to darkness is prolonged.

Cause:Nyctalopia is due to a disorder of the cells in the retina that are responsible for vision in dim light. It has many causes, including nearsightedness, glaucoma, cataracts, retinitis pigmentosa, or vitamin A deficiency.

Treatment:Treatment for nyctalopia will depend upon its cause. Treatment may be as simple as a new prescription for your eyeglasses or switching glaucoma medications, or it may require surgery in cases of cataracts.