WHAT IS GLAUCOMA?
Glaucoma is the name given to a group of eye conditions which damage the optic nerve and affects the side vision in a distinctive manner. It is the leading cause of preventable blindness in the UK with about half a million sufferers and accounts for about one in eight of those registered as blind or partially sighted. Over the age of 40 the incidence is about 1-2% and 25% of cases are undiagnosed or not detected until it is too late to prevent some blindness. It is caused by raised eye pressure in most cases or by poor blood flow to the optic nerve. Over 8% of the population over 70 years of age have significantly raised eye pressure and the Afro-Caribbean and Asian population are six times more likely to suffer from glaucoma.
According to the RNIB in 1996 glaucoma accounted for over 11% of those registered as blind or partially sighted.
There are two main types of glaucoma; 1) open angle or chronic glaucoma and 2) closed angle or acute glaucoma.
The most prevalent type is "open angle" glaucoma in which the patient suffers no pain or redness of the eye but the side vision is affected leaving only usable central vision or tunnel vision as the disease progresses, leading to complete blindness if no treatment is provided. The blindness from the damaged eye may not be noticed as the other eye will be seeing normally. However, a regular eye examination will detect the problem before things are too advanced and once detected, treatment can be implemented to prevent further visual loss.
The second type, acute glaucoma, accounts for less than one tenth of the glaucomas and is accompanied by redness of the eye, pain and blurred vision and must be treated within 48 hours to prevent permanent visual loss. East Asian parentage is a risk factor.
Treatment for open angle glaucoma is usually in the form of eye drops twice per day, usually Timolol maleate now, although Pilocarpine, two to four times daily, was used for many years. Timolol reduces the production of fluid (aqueous) in the eye but can cause bronchiolar spasm and slow metabolism so it is not used for asthma sufferers or patients with heart problems. More recently newer, more effective, though costly, eye drops have become available. These include the prostaglandin analogues, Latanoprost and Travatan, which increase the outflow of fluid (uveo-scleral outflow) although they change the eye colour and increase eyelash length. Lasers can be used to treat glaucoma. The argon laser trabeculoplasty painless procedure lasts for 15 minutes works well on 80% of the population and the Nd:YAG laser to make a hole in the iris. Marijuana smoking lowers eye pressure but it also reduces blood flow to the optic nerve head.