Color vision deficiency (also called color blindness) is a vision disorder in which a person sees colors differently than other people see them or has difficulty distinguishing shades of some colors. The disorder occurs when malfunctioning receptor cells for color…
Cancer cells can spread through the bloodstream or the lymphatic system from a tumor in one area of the body to form a tumor in another part of the body, including in the eye. Treatments A secondary tumor is treated…
Retinoblastoma is a rare, malignant tumor of the retina that occurs in one or both eyes, usually in children between ages 2 and 3. Because retinoblastoma is often inherited, you should seek genetic counseling before having children if you know…
Malignant melanoma is a cancer that can affect the eyes as well as the skin, and is the most common type of cancer that occurs inside the eye. Malignant melanoma usually occurs in the choroid (the layer of blood vessels…
Optic neuritis is inflammation of the optic nerve, which disrupts the flow of signals from the retina to the brain and impairs vision. The condition usually develops between ages 20 and 40. In rare cases, optic neuritis results from an…
Choroiditis is inflammation of the choroid, the layer of blood vessels beneath the retina (the light-sensitive membrane lining the back of the eye) that supplies the eye with oxygen and nutrients. In some cases, the retina and the vitreous fluid…
The central retinal vein carries oxygen-depleted blood away from the retina (the light-sensitive membrane lining the back of the eye). In rare cases, usually in middle-aged or older people, the central retinal vein or one of its branches becomes blocked…
The retina (the light-sensitive membrane lining the back of the eye) receives its blood supply from the central retinal artery, a tiny blood vessel that enters the back of the eye through the optic nerve. Sometimes, usually in middle-aged or…
Retinal detachment occurs when the retina—the light-sensitive membrane that lines the inside of the back of the eye—lifts away from the choroid, the layer of blood vessels beneath the retina that supplies the eye with oxygen and nutrients. In most…
Diabetic retinopathy is an eye disorder in which changes in the blood vessels of the retina (the light-sensitive membrane that lines the back of the eye) can lead to vision loss or blindness. The disorder occurs in people who have…
Macular degeneration is a disease characterized by irreversible deterioration of the light-sensitive cells of the macula—the part of the retina (the light-sensitive membrane lining the back of the eye) that provides sharp focus in the center of the field of…
Glaucoma Glaucoma is a group of eye diseases in which damage to the optic nerve leads to loss of vision. The most common type of glaucoma, called chronic open-angle glaucoma, usually develops gradually over a number of years. A clear,…
A cataract is clouding of the lens of the eye. As protein fibers in the lens clump together, the clouding worsens and prevents some light rays from passing through the lens and reaching the retina, the light-sensitive membrane that lines…