World Glaucoma Week, 8th to 14th March, is a joint initiative between the World Glaucoma Association and the World Glaucoma Patient Association to raise awareness of this silent robber of vision. Glaucoma is a group of eye diseases that cause progressive damage of the optic nerve at the point where it leaves the eye to carry visual information to the brain. If left untreated, most types of glaucoma progress without warning nor obvious symptoms towards gradually worsening visual damage and may eventually lead to blindness. Glaucoma is the second most common cause of blindness worldwide. Once incurred, visual damage is generally irreversible, which has led to glaucoma being described as the "silent blinding disease" or the "sneak thief of sight".
TYPES OF GLAUCOMA
There are several types of glaucoma, the two main kinds being open-angle glaucoma and angle-closure glaucoma. Secondary glaucoma may occur as a complication of other visual disorders, such as cataracts or diabetes, but the vast majority is primary. Less common types of glaucoma include normal-tension glaucoma and pigmentary glaucoma. Some forms of glaucoma may occur in infancy or childhood, and although rare, it can be present at birth. In all types of glaucoma, the optic nerve is gradually damaged.
CAUSES OF GLAUCOMA
Aqueous humor is a clear fluid which circulates in the inner eye, keeping it firm and nourishing it. It usually flows out of the eye through a channel, but if for any reason drainage is blocked, pressure builds within the eye, gradually damaging the optic nerve. It was thought that the cause of most or all glaucomas was high pressure within the eye, but it has been found that even people without abnormally high intraocular pressure may suffer from glaucoma.
RISK FACTORS FOR GLAUCOMA
Glaucoma typically affects adults over the age of 40, although it can occur in younger adults, children and even infants. The earlier the onset of the condition, the more aggressive it tends to be. Family history and ethnicity have a role to play. Other risk factors include a high degree of shortsightedness or farsightedness, diabetes, trauma to the eye and certain medications, particularly corticosteroids.
SYMPTOMS OF GLAUCOMA
In the early stages most people with chronic glaucoma are unaware that they have the condition which develops slowly and without symptoms. The main sign is usually a decrease in peripheral or side vision, but by the time this is noticed some irreversible vision loss and damage to the nerve has already occurred. Acute or angle-closure glaucoma occurs more rapidly with more obvious and severe symptoms and damage, as the intraocular pressure rises quickly. Symptoms experienced may include sudden severe pain in one eye, nausea, partial loss of vision, blurred vision and halos around lights. In such cases, medical intervention should be sought immediately.
DIAGNOSIS OF GLAUCOMA
Glaucoma can be detected as part of a routine eye examination. Tonometry assesses eye pressure, and a visual field test may be performed to measure the loss of peripheral vision. The pupils may be dilated to give the optometrist a clear view of the retina and the ability to evaluate optic nerve damage. Photographs may be taken so that changes can be monitored from visit to visit. Rather than waiting for symptoms by which time there may be a loss of vision, visit your optometrist regularly for an eye examination. Early detection leads to early management and a better prognosis!
TREATMENT OF GLAUCOMA
There is no cure for glaucoma as yet, and vision loss is irreversible. However, treatment can slow down or even stop the progression of the disease. Eye drops, oral medication, laser surgery or microsurgery are treatment options to lower eye pressure. Discuss these with your optometrist who will guide you with regard to the most appropriate treatment for you and refer you to an ophthalmologist if necessary.
PREVENTION OF GLAUCOMA
While glaucoma cannot be prevented, a healthy lifestyle and maintenance of physical as well as eye health may minimise the risk and help protect vision. Cutting back, or preferably, giving up smoking reduces the risk of chronic disease, including eye disease. Exercise facilitates blood circulation throughout the body, including the eyes. Know and inform your optometrist about your family history, particularly as it relates to eye conditions. Protect your eyes from the harmful effects of the sun.
Following a balanced diet is simple common sense, and some research points to specific foods that should be avoided and those that should be included in the diet if one has glaucoma. Avoid foods linked with high cholesterol levels and blood vessel damage which can occur anywhere in the body including the tiny blood vessels in the eyes. Cut back on caffeine and substitute coffee with antioxidant-rich green tea. Keep salt consumption to a minimum.
Foods rich in omega 3 fatty acids are recommended for eye health. Include sea food, leafy green vegetables, eggplant, goji berries, blackcurrants and oranges in your diet. Cocoa, red wine and green tea contain flavonoids which have powerful antioxidant and neuroprotective properties.
A glaucoma diagnosis is often daunting and difficult to accept, and it may come as a shock when there were no warning signs or indications to alert the person to its existence. It is a life-long condition, but it can be effectively managed. Understanding it and taking responsibility for being part of the treatment process, having regular eye examinations and discussing concerns with your optometrist play a role in helping to protect the eyes against further damage.