As the optic nerve is slowly damaged, characteristically shaped blind areas develop that can progress to loss of vision or even total blindness, usually painlessly.
Glaucoma is dangerous because most people do not notice any symptoms until after permanent damage has been done. If it is detected early, treatment can usually prevent irreparable harm. In the past doctors used to think that any eye pressure above 20 was glaucoma and that as long as the pressure was reduced to less than 20 no further damage would occur.
Open angle (also called chronic open angle glaucoma and chronic simple glaucoma) is the most common type, accounting for about 90 percent of all glaucoma. Open angle glaucoma usually affects both eyes, though one eye may be involved earlier or more severely than the other. It usually does not occur until middle life, though sometimes younger individuals are affected. The condition tends to be hereditary but the lack of a family history does not rule out glaucoma. The high pressure in the eyes is not the same as high blood pressure.
The other common form of glaucoma is angle closure glaucoma. This form of glaucoma can result in much more rapid vision loss and thus needs to be treated immediately. While open angle glaucoma can exist for many years lurking in the background, angle closure glaucoma usually presents with a very painful red eye accompanied by blurry vision, extreme pain as well as nausea and vomiting. It is caused by the sudden blockage of fluid circulation in the eye, specifically fluid getting into the “drain” or angle of the eye. This is where the iris (the colored part) meets the cornea (the clear covering in the front). When the angle closes the fluid that the eye naturally produces has nowhere to exit or drain. This causes the pressure in the eye to rise rapidly. Normal eye pressure ranges to about 20 mm Hg but with an attack of glaucoma can go as high as 70 mm Hg. from This rapid rise will often lead to pronounced vision loss in hours to days rather than over months to years as seen in open angle glaucoma.
While medications are administered the mainstay of treatment is with a laser iridotomy to hopefully break the attack. This treatment creates a small hole in the iris where fluid can now pass which in turn helps the drain, or angle, open to allow fluid passage. I use the analogy of our bathroom sinks at home. If you were to put the drain plug in and leave the water on, eventually the sink will fill. The auxiliary drain in the front of the sink however prevents the water from overflowing onto the floor. The laser iridotomy creates an opening that acts like the auxiliary drain in the bathroom sink. One important fact is that once you have an attack in 1 eye you are at great risk for an attack in the other eye. We will always perform a preventative laser in the unaffected eye to prevent a future attack. While no procedure is foolproof, the likelihood of an angle closure attack after a successful iridotomy is close to zero. The laser treatment itself is easily performed and with no pain or discomfort. Only eye drops are used as anesthesia and activities do not have to be limited following the procedure. At North Shore Eye Care, Dr. Andrew Bainnson, a fellowship trained glaucoma specialist. North Shore Eye Care has the most advanced and high tech equipment to help in the diagnosis and treatment of glaucoma as well as most other common eye conditions such as diabetes, macular degeneration, and cataracts.