By Romila Boodram
Every year, dozens of persons are diagnosed with glaucoma at the Georgetown Public Hospital Corporation (GPHC), some of whom eventually lose their vision. To emphasise its importance a week is dedicated annually to raising awareness about the disease. From today to next Saturday, World Glaucoma Week will be observed worldwide.
Glaucoma is an eye disease in which the optic nerve (the nerve primarily responsible for sight) is damaged in a characteristic pattern. This can permanently damage vision in the affected eye (s) and lead to blindness if left untreated.
During a recent interview with this publication, Dr. Shailendra Sugrim, an ophthalmologist at the GPHC explained that glaucoma can be categorised into two types: Open-Angle and Closed-Angle.
The angle refers to the area between the iris and cornea, through which fluid must flow to escape via the trabecular meshwork (a sieve-like structure). In Open-angle glaucoma, even though the angle is wide and open, slow clogging of the drainage canals can increase the eye pressure. In Closed-Angle glaucoma there is a closed or narrow angle between the iris and cornea. As a result drainage is obstructed and results in a sudden rise in intraocular pressure.
Dr. Sugrim related that glaucoma is generally a disease of aging, more frequent in patients over age 60, but if a person has other risk factors (genetic, structural and systemic) that can affect their drainage system, it can occur in younger persons. The ophthalmologist noted that Open-Angle Glaucoma is more common locally “In particular, patients of Afro-Guyanese origin are more prone to develop Open-Angle glaucoma and are more likely to have family members suffering from glaucoma. It has also been found that in Afro-Guyanese patients, glaucoma is very severe and more difficult to treat.”
Symptoms and Signs
Dr. Sugrim weighed in on the significance of early detection. “This is an important issue for us to be conscious about, because in the early stages of Open-Angle glaucoma, there are no symptoms or complaints. Hence a patient may be suffering with glaucoma for many years and not know it,” he noted. He added that “…in some cases, where patients are very sensitive to visual changes, they may notice spots in their vision. These patients may complain of seeing a black spot or they may complain of missing words on a page. In the advanced stages of glaucoma patients lose their peripheral vision (their vision appears as if they are looking through a dark tunnel with only a small central hole.)”
At the GPHC, once a patient is diagnosed with glaucoma, he or she will be treated based on the severity of their condition. There are many ways to treat glaucoma, these include anti-glaucoma eye drops, laser treatment and surgery.
“The usual pattern is to start patients on anti-glaucoma eye drops and some patients can be prescribed with as much as four different eye drops. If eye drops fail to control glaucoma, patients can then be given the option of having laser treatment or glaucoma surgery,” Dr. Sugrim said.
Management of glaucoma includes constant follow-up visits to the clinic to have eye pressure checked and for the ophthalmologist to evaluate whether the drops are controlling the glaucoma.
If a patient has to undergo surgery, the most common that is offered by the GPHC, is a Trabeculectomy. During this procedure, a piece of tissue in the drainage angle of the eye is removed, creating an opening. The opening is partially covered with a flap of tissue from the sclera (the white part of the eye) and the conjunctiva (the clear thin covering over the sclera.).
The new opening allows fluid to drain out of the eye, bypassing the clogged drainage channels of the trabecular meshwork. As the fluid flows through the new drainage opening, the tissue over the opening rises to form a little blister or bubble, called a bleb.
The bleb is located where the sclera, or white of the eye, joins the iris, the coloured part of the eye. After surgery, the specialist would look at the bleb to make sure that fluid is still draining out of the new opening.
Source: http://www.kaieteurnewsonline.com/2013/03/10/glaucoma-the-silent-killer-of-sight/