Glaucoma: the silent thief of sight affecting South Africa’s vision

In South Africa, glaucoma remains one of the leading causes of preventable blindness, yet a staggering 95% of those suffering from the condition are completely unaware until it is too late. Amid World Glaucoma Week (March 8-14), Dr Marissa Willemse, a specialist ophthalmologist and president of the South African Glaucoma Society (SAGS), warns that only 1 in 20 individuals know they are affected. Alarmingly, 50% will have experienced vision loss in one eye by the time they consult an ophthalmologist for the first time.

Often termed the “silent thief of sight,” glaucoma is an umbrella term for a collection of eye conditions that gradually damage the optic nerve, which is responsible for transmitting visual information from the eye to the brain. Untreated, this pressure can result in irreversible damage and eventual blindness. However, Dr Willemse emphasises that glaucoma is more than just an issue of vision; it can severely undermine daily living, affecting individuals’ independence, work, mobility and mental health long before the realisation of an issue emerges.

“Vision loss from glaucoma often starts in the periphery, creating gaps in vision that go unnoticed until they interfere with everyday activities,” Dr Willemse explains. “Even early vision loss can have significant impacts on daily routines: driving, reading, using digital devices, cooking, or navigating unfamiliar spaces.” These disruptions can lead to feelings of anxiety, depression and even social isolation, profoundly affecting an individual's quality of life.

Statistics reveal a troubling trend; in Sub-Saharan Africa, around 4.16% of the population aged 40 and above struggle with glaucoma, with the incidence reported as being higher among black individuals (5–7%) compared to their Caucasian counterparts (3–5%). The fight against this condition is further complicated by a lack of awareness, delayed diagnoses, poor follow-ups, and low compliance with treatment regimens.

Dr Willemse underscores the critical need for greater awareness surrounding glaucoma, as it often exhibits no noticeable symptoms in its early stages. As intraocular pressure escalates, damage to the optic nerve occurs, leading to progressive vision loss. By the time patients notice warning signs — such as gradual loss of peripheral vision or blurred sight — it is frequently already too late to reverse damage.

Who is most at risk?

The risk factors for developing glaucoma are varied, and regular check-ups with an ophthalmologist are imperative for early detection. Key factors include:

• Age: Risk increases with age, especially for those over 60 years; however, in Africa, those as young as 40 are affected.
• Family history: A familial predisposition significantly raises an individual’s risk.
• Race or ethnicity: Certain demographics, including African Americans, Africans, Hispanics, and Asians, are at an elevated risk.
• High intraocular pressure: Individuals with elevated IOP are more likely to develop glaucoma, though this is not a rule.
• Thin central corneal thickness: Thinner corneas have been linked to higher susceptibility.
• Medical conditions: Disorders such as diabetes, hypertension, and cardiovascular issues can contribute to risk.
• Previous eye injuries or surgeries: Trauma to the eye or past procedures can heighten risk.
• Near-sightedness: This condition increases the likelihood of glaucoma.

Symptoms

Symptoms tend to manifest gradually, and include:

• Gradual loss of peripheral vision: Often causing tunnel vision or blind spots.
• Blurred vision: This may indicate damage to the optic nerve.
• Halos around lights: Particularly noticeable at night.
• Eye pain or redness: Rare but can occur in some cases.
• Nausea or vomiting: Especially in severe cases, emergency treatment is critical.

Screening for glaucoma

Screening recommendations suggest individuals under 40 undergo screenings every 2-4 years, those aged 40 to 60 every 2-3 years, and individuals over 60 annually. Screening methods typically involve comprehensive eye examinations, including:

• Tonometry: Measuring intraocular pressure.
• Ophthalmoscopy: Assessing the optic nerve for potential damage.
• Perimetry: Testing peripheral vision to identify blind spots.
• Gonioscopy: Evaluating the drainage angle of the eye.
• Optical Coherence Tomography: Monitoring nerve fibre layers for early changes.

Treatment options

Upon completing screening, an ophthalmologist will establish a tailored treatment plan aimed at lowering intraocular pressure to prevent further optic nerve damage. Common treatments include:

• Medicated eye drops: Used chronically to manage intraocular pressure.
• Laser therapy: Improves fluid drainage from the eye.
• Surgery: Considered when other treatments are ineffective.

Dr Willemse calls for increased awareness of glaucoma, advocating for regular eye examinations and early detection. Access to comprehensive eye care services, particularly in under-resourced communities, is vital for managing this condition and preserving patients’ vision.

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