What are the common eye diseases that occur as one ages?

In addition to normal changes that occur with age, older adults are more likely to experience a dramatic decline in their visual abilities, leading to some forms of partial sight. The most common forms of partial sight in older people are:

• Cataracts - A condition where the previously clear, colorless crystalline lens becomes colored, dark, and cloudy (or opaque). Cataracts reduce retinal illuminance and increase light scattering. Subjects with cataracts complain of poor visual acuity and have difficulty seeing under low light levels. To improve visual acuity, light levels can be increased, but this may also increase glare due to scattering and, therefore, can be counterproductive.
• Glaucoma - Often called the "silent thief of sight," glaucoma results from too much aqueous fluid in the anterior chamber of the eye. As fluid pressure increases, nutrition to the retina is cut off, killing neural cells and ultimately leading to "tunnel vision." Glaucoma affects peripheral vision long before it damages central vision. Chronically elevated eye pressure can cause optic nerve atrophy and result in total blindness.
• Age Related Macular Degeneration - The macula includes the fovea that provides acute vision. Macular degeneration can have two causes: either atrophy of neural tissue (the, so-called, "dry" type); or severe hemorrhagic disease (the, so-called, "wet" type). Visual acuity often drops to less than 20/400. The rest of the retina remains largely unaffected, so peripheral vision remains normal.

Some Other Common Retinal Disorders - Diabetic Retinopathy and Retinal Detachment:

• Diabetic Retinopathy - This is a progressive deterioration of the retina resulting from diabetes mellitus, a lack of insulin in the blood. Very small blood vessels burst and stop feeding the retina (ischemia). When nutrition to the neural cells is cut off, the affected region of the visual field will be lost. Damage can occur at any retinal location.
• Retinal Detachment - This happens when the retina becomes separated from the choroid, the back of the eye. Retinal detachment rarely occurs as an isolated event but is associated with trauma to the retina or with other degenerative problems. It can also be a late complication of cataract surgery.