Illinois Society for the Prevention of Blindness

The loss of sight is gradual. It begins as loss of side vision, then it continues toward the center of vision, until finally all sight is destroyed. Because the visual loss is gradual in the early stages of the disease, few signs of the disorder are recognized.

Each year, about 4,000 Americans are blinded by glaucoma even though the disease can be controlled and blindness prevented through early detection and immediate treatment. In the United States, 2.3 million Americans over the age of 40 have glaucoma. More than 100,000 people over the age of 40 have glaucoma in Illinois alone.

Affected persons are unaware of the progressive loss of sight. They may see objects clearly, even read a wall chart with normal central vision, but, at the same time, may be blind in the outer areas of the visual field, where sight has been lost due to increased eye pressure. A wall chart test will not disclose this creeping blindness.

People with normal vision can stand at a street intersection and see traffic from both directions. Those with advanced glaucoma can see only straight ahead, as if they were looking through a long tube.

Glaucoma permanently narrows the visual field until only a small area of straight-ahead vision remains, then none at all. The tragedy is that sight destroyed by glaucoma can never be restored.