Glaucoma is an eye disease that gradually causes vision loss. Experts have warned that people with glaucoma do not ‘feel’ the disease until their vision is almost lost, although medications and surgery are available, reports Sade Oguntola.

As a teacher, Mrs. Kike Alabi, realised her eye was failing because now at age 45, each time she looks at any object, she sees a circle of darkness enveloping the object. Initially, she did not give much thought to it as a problem because a friend introduced her to a roadside optician who recommended a pair of spectacles.

Over six months of persistent use of the spectacles, Mrs. Alabi’s sight problem continued to deteriorate and she was forced to go to an eye specialist in the city.

“I was scared because, without a good sight as a teacher and a part-time seamstress life was going to be difficult,” reiterated Mrs. Alabi, while at the hospital.

Mrs. Alabi was diagnosed with glaucoma, a silent thief of sight. This is so because the affected person usually will not feel any pain or notice the loss of vision in the early stages until the disease has progressed significantly.

Obviously, blindness is better imagined than experienced, especially where it is as a result of glaucoma, an irreversible cause of blindness.  Every five seconds, someone in the world becomes blind. Every minute, a child becomes blind.

In Nigeria, approximately 1.2 million people are blind and 4.25 million adults aged 40 years and over, have moderate to severe visual impairment or blindness. The situation of blindness is really worrisome.

Unfortunately, Dr. Adeyinka Asaye, a consultant ophthalmologist while speaking at the 12th Faculty of Ophthalmology lecture entitled “Glaucoma blindness: Facts, Fancies and Fables”, stated that the number of blind people will almost double by the year 2020 unless concerted action is taken.

According to Dr. Asaye, “80 per cent of vision loss is avoidable” because they are either preventable or treatable with currently available knowledge and technology.

The major causes of blindness are cataract (43 per cent), glaucoma (0.7 per cent), river blindness and injury to cornea, a part of the eye. But nobody wants to lose his or her sight.  Certainly, sight is precious, thus explaining the Yoruba parlance, Oju lóba ara. The reality, however, is that the estimated number of blind persons in Nigeria is 1.1 million.”

Interestingly, available statistics on glaucoma, the second highest cause of global blindness, indicate that about 6.5 per cent of people over 40 years in Nigeria had developed this eye disease.

Glaucoma is an eye disease that gradually causes vision loss. It happens when the optic nerve, which carries images from the eye to the brain, becomes damaged. In most cases, the optic nerve becomes damaged by the pressure inside the eye called intraocular pressure (IOP).

When the pressure in the eye is too high, it pushes on the cells that make up the optic nerve. Over time, this pressure damages the cells and eventually causes them to die. This is what causes permanent vision loss. But the damage to the optic nerve can happen slowly, so it is difficult to notice at first.

There are two many types of glaucoma. According to Dr. Ashaye, “the commonest type of glaucoma is the open-angle glaucoma, which occurs when the exist for the fluid inside the eye becomes smaller over time, so resulting in the IOP rising slowly  and causing the optic nerve to be damaged without the individual noticing.”

Given that glaucoma is a continuum, progressing from undetectable to symptomless, to visual impairment and then blindness, she declared, “the ophthalmologist tries to prevent this continuum from getting to the end stage. However, factors such as increased IOP when glaucoma was initially diagnosed, thickness of cornea and age may accelerate its progression to the end stage, which is blindness.”

Certainly, some people are prone to getting glaucoma. Older people, especially after age 60; people with African and Asian heritage; a family history of glaucoma; high eye pressure, being nearsighted, diseases like hypertension and migraine and a previous eye injuries or eye surgery that damaged the pressure regulating system of the eye are more likely to develop glaucoma than others.

However according to Dr. Ashaye, anyone can get glaucoma and “the likelihood of getting it tends to double with each decade of life after 40 years. It has a familiar occurrence. For instance, if a sibling is diagnosed with glaucoma, the likelihood of diagnosis in another sibling is 3.7; 2.2 for parents and 1.1 for child. The shortsighted person needs regular evaluation, more so when he is 40 years and over.”

It is not all bad news about glaucoma. “Lifestyle changes, especially exercise, have been documented to cause changes in IOP,” explained Dr. Ashaye.

Like many other chronic diseases, which cause death and disability worldwide, a change in dietary habits, physical exercise and tobacco control has a major impact in reducing the likelihood of developing them.
Established scientific evidence suggests that eating more fruits and vegetables as well as nuts and whole grains; swapping saturated animal fats with unsaturated vegetable oil-based fats in one’s diet; reduction in salt, fat and sugary foods and stopping smoking could reduce the likelihood of a person developing glaucoma.

However, medical doctors claims treating glaucoma is aimed at preserving quality of life by halting progressive visual loss. There are medications (eye drops) available to lower the pressure in the eye. Laser therapy or surgery can be used if the medications are not enough. But these treatments must be started early because once vision is lost, it cannot be recovered.

Nonetheless, Dr. Ashaye declared, “anyone on medication should stick with his or her programme of treatment. Adherence to glaucoma therapy preserves the vision in glaucoma.”

Studies found that non-adherence to drug use and/or follow-up is vey high. In UCH clinic population, for instance, 60.5 per cent dropped out within one year. Out of these, 43.1 per cent dropped out after their first follow-up visit. The risk factors for drop-out included younger age, males, cost of eye drop, patient with mild/moderate visual dysfunction and distance from health facilities.

Certainly, glaucoma and its treatments have several challenges. “We need sustainable, comprehensive eye care services through promotive, curative and preventive eye care practice to prevent morbidity and mortality from all chronic diseases,” Dr. Ashaye said.

“Our strategy must be to integrate glaucoma case finding into cataract programmes and community screening for blinding eye diseases such as diabetic eye disease, macula degeneration and other eye problems such as poor sight.”

When screening for glaucoma is done in the context of screening for other blinding diseases, aside being cost effective, there is a higher chance of early detection of glaucoma cases at the community level.

No doubt, as Dr. Ashaye pointed out, there is the need for continued research on such things as more effective and cheap treatment for glaucoma as well as the genetics that control this thief of sight.

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