Preserving the gift of sight

Posted on March 16, 2018

Eyesight is something that is easily taken for granted. It is so fundamental to a person’s being that it is difficult to imagine life without it. Unfortunately, many people face the reality of a slow, progressive loss of vision that eventually results in their sight being lost completely. Blindness can have a negative impact on family units, standards of living and the economy.

Glaucoma is one of the leading causes of blindness in the world. World Glaucoma Week, from 11 to 17 March 2018, aims to raise awareness of glaucoma and the vital importance of regular eye checks for early detection, and preserving sight for as long as possible.

The University of Pretoria’s Department of Ophthalmology, in the Faculty of Health Sciences, is committed to better understanding the eye disease described as ‘the thief of sight’ by investing in research, training of medical students and treatment of patients at Steve Biko Academic Hospital.

Glaucoma is a complex disease that damages the eye’s optic nerve, causing irreversible blindness. The damage is usually the result of a build-up of fluid in the front part of the eye. This extra fluid causes excess pressure in the eye which damages the optic nerve. While increased intraocular pressure (IOP) is regarded as a significant contributing factor, people whose IOP is within the normal range can also develop glaucoma.

Because peripheral vision is typically lost first, people often go for an eye test when the disease is very advanced and central vision is already impaired. The disease often goes unnoticed because it progresses slowly and painlessly. Dr Priscilla Makunyane, Head of the Department of Ophthalmology, says many patients are only diagnosed incidentally, usually going to optometrists or ophthalmologists for minor ailments, only to discover that their sight is dramatically reduced.

If glaucoma is detected in its early stages, it can be treated medically or surgically, significantly reducing the chance of complete loss of sight. Early detection and intervention in the form of topical medication, surgical procedures or laser treatment can certainly control glaucoma, and the damage caused can be minimised. Glaucoma cannot be healed, but it can be controlled, just like other chronic conditions such as hypertension.

There are two major types of glaucoma: primary open-angle glaucoma and angle-closure glaucoma, or closed-angle glaucoma. Primary open-angle glaucoma is the most common type and happens gradually over time, where the eye fails to drain fluid sufficiently resulting in increased IOP. Closed-angle glaucoma occurs when the iris is too close to the drainage angle of the eye, causing a blockage. When the drainage angle is completely blocked, eye pressure increases. While both eyes are usually affected by glaucoma, there are rare cases in which the disease affects one eye only.

Regular eye examinations are critical to identify the condition and assess its progression. These examinations should measure the visual acuity (clarity of vision) and the IOP. The optic disc and optic nerve, as well as the nerve fibre, are also tested to assess their level of function.

Dr Makunyane explains that compliance with treatment is often a challenge, particularly in cases of primary open-angle glaucoma, because there is no pain. Patients often get tired or lose interest in using the treatment, which involves instilling eye drops that can be irritating to the eye. Because of these challenges, Dr Makunyane stresses the need for adequate patient education on the importance of treatment.

Risk factors for primary open-angle glaucoma are a high IOP, advanced age, short-sightedness, diabetes, a family history of glaucoma, the black race and some retinal diseases. Because glaucoma can run in families, Dr Makunyane strongly advises that time should be invested in knowing one’s family disease profile. Furthermore, regular eye tests are essential for all adults.

As part of the South African Glaucoma Society, the Department of Ophthalmology has been interacting with communities during World Glaucoma Week. Information has been shared about the disease and awareness is created around the importance of regular eye tests and treatment.

The Department of is currently involved in research that studies medically controlled primary open-angle glaucoma patients who are at risk of glaucoma progression. It has also recently acquired a new micropulse cyclophotocoagulation laser machine, which facilitates treatment of glaucoma by reducing aqueous secretion and IOP. This machine has opened new avenues for patient management and research in the Department.

- Author Louise de Bruin

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