Around 10% of people with glaucoma will eventually go blind, even with treatment. Because glaucoma often does not generate symptoms, many people have it and do not know. Roughly 1.5 million Americans are diagnosed with glaucoma, but it is estimated that twice that many people have the disease. African-Americans are particularly at risk with rates 4-5 times higher than the general population. African-Americans are also much more likely to go blind from glaucoma. The reasons for this are not entirely understood, but genetics and family history seem to play a large role.
There are several forms of glaucoma, but by far the most common is open-angle glaucoma. This type of glaucoma is caused by a build-up of pressure in the eye. In a healthy eye, a mix of water and amino acids known as aqueous humor circulates from the ciliary bodies below the iris, through the pupil, and out through the trabecular meshwork. This fluid provides protein and sugar to the eye tissue. If the fluid cannot drain through the trabecular meshwork, it builds up, increasing pressure in the eye. The trabecular meshwork is a spongy tissue that becomes less permeable with age, and may also be damaged by injury or disease. The pressure will rip the optic fibers, causing spots of blindness and loss of peripheral vision.
Neovascular glaucoma is a rare type of glaucoma caused by the development of new blood vessels. Circulatory problems in the eye can cause abnormal blood vessel growth, which can scar the trabecular meshwork. Fluid can’t drain through the scared tissue. Blood may also build up in the eye as well in this form of the disease. Another relatively common form of glaucoma is caused by exfoliation syndrome. Exfoliation syndrome occurs when clumps of protein fall into the aqueous humor and clog the trabecular meshwork. Acute Angle-Closure Glaucoma occurs when the iris enlarges and pinches the trabecular meshwork closed. The sudden build-up of aqueous humor can destroy eye tissue rapidly. This is treated by using a laser to cut back the iris. These types of glaucoma can usually be detected with an air puff pressure test.
Sometimes the optic nerve will degenerate due to poor circulation. This is known as low-pressure glaucoma because it is not caused by a buildup of fluid and cannot be detected by a pressure test.
Some medications reduce pressure by causing the eye to produce less fluid. Some medications help the fluid drain. Glaucoma eye drops can be prohibitively expensive and can irritate the surface of the eye. Medical marijuana has proven effective at relieving eye-pressure temporarily, but requires such high and frequent dosing that many patients find the side effects untenable. New technology allows medication to be delivered through a special contact lens. Perforating the trabecular meshwork with a laser often helps relieve pressure, but can be risky and expensive. There is no “cure” for glaucoma, but reducing the pressure inside the eye helps slow progression of the disease. Generally, vision lost from nerve damage will never regenerate.
The Social Security Administration has a listing of impairments which qualify for disability benefits known as the Blue Book. Glaucoma is not specifically listed. However, there are two listings- loss of central visual acuity and loss of visual efficiency- the people with severe glaucoma are likely to meet. Loss of central visual acuity is defined as having worse than 20/200 vision in the better eye even with glasses or contacts. Loss of visual efficiency can either by a visual efficiency percentage of 20 or less, or a visual impairment value of 1.00 or greater in the better eye, with glasses or contacts. The visual efficiency percentage and impairment values are measured by testing both central and peripheral vision. Even if your vision has not worsened to the point of qualifying for the listing, you may be eligible for benefits if your vision problems prevent you from working. An experienced long term disability lawyer can help you ascertain whether you qualify or not.