Understanding glaucoma

Are you getting up in age and a bit worried about your vision? Do you have a medical condition such as diabetes and are concerned about how it will affect your sight? Do you think you may be at risk for glaucoma?

Dr Lizette Mowatt, consultant ophthalmologist at the University Hospital of the West Indies (UHWI), said glaucoma is characterised by an increase in the pressure within the eye.

“It is important to note that over time the increased eye pressure can damage the eye nerve (optic nerve). If this nerve becomes damaged then visual loss or blindness can be the end result,” she said.

There are two main types of glaucoma: primary open angle glaucoma (POAG) and narrow angle glaucoma. The most common type of glaucoma is POAG, which occurs equally in men and women.

Fifteen per cent of patients who are 70 years or older have glaucoma. POAG occurs in about two per cent of patients over 40 years of age. Women, especially of Asian origin, are more prone to getting narrow angle glaucoma. Both types, if not treated, can cause loss of vision.

According to Dr Mowatt, the main risk factors for developing POAG are:
a) Increased intraocular pressure, that is, increased pressure build-up inside the eye
b) Age. Although it may occur as early as the 30s, it is more commonly seen in patients over 50.
c) African/Afro Caribbean or Afro American patients are more likely to develop it and have a more aggressive course.
d) If a relative has glaucoma you are at risk of developing it.
e) Diabetes
f) Myopia (nearsightedness)

Dr Mowatt, also a senior lecturer at the University of the West Indies, said that unfortunately, primary open angle glaucoma has no symptoms. Most patients only find out when they have lost most of their vision. At this stage it is irreversible. Glaucoma can only be prevented by being screened by an eye doctor, who will check the pressure in your eye as well as the health of your eye nerve.

If you are concerned that you may have glaucoma you must visit your ophthalmologist. Dr Mowatt recommends that all those who have relatives (parents, aunts, uncles, siblings, cousins) with glaucoma must be screened by age 40.

Once you are diagnosed with glaucoma, treatment with anti-glaucoma eyedrops will be started. These drops are lifelong as there is no cure for glaucoma. If you don’t take the drops every day you can go blind. You will also need to be monitored by an eye doctor as you may need additional eyedrops as you get older. The regular visits and medications can prevent you from losing your vision.

The first line of treatment for POAG, which is the most common, is eyedrops. In order to be effective, the drops must be used daily and as prescribed. Taking your eye drops daily at the recommended time is the initial management of glaucoma. If the eyedrops don’t work, laser treatment may be done. Argon Laser Trabeculectomy or Selective Laser Trabeculoplasty can reduce the pressure in the eye, thereby saving vision.

Surgery is done when everything else fails. During the surgery (trabeculectomy), a drainage pathway is made to improve the outflow of the fluid from your eye in order to lower the pressure so that the eye nerve is not damaged. Note that glaucoma cannot be prevented. It is very important that if you have any of the risk factors that you see your eye doctor for screening. If diagnosed with glaucoma, you must take your medications as prescribed. If glaucoma is diagnosed early and treated consistently and monitored regularly by your eye doctor, then it is likely that you will maintain good vision.