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Eyes – the checks that catch problems before you notice

Glaucoma and diabetic eye disease steal sight painlessly and irreversibly. Who needs testing, how often, and what cannot wait.

The conditions that give no warning

The two leading causes of preventable blindness in South African adults both do their damage silently. Glaucoma destroys peripheral vision so gradually that the brain fills in the gaps, and a person often notices nothing until a large amount is permanently gone. Diabetic retinopathy damages the retina without pain or blurring until it is advanced.

Neither can be reversed. Both can be halted if found early. That is the entire case for testing eyes you have no complaint about.

Who should be tested, and when

  • Everyone with diabetes: a retinal examination at diagnosis and then at the interval your clinic sets, usually yearly. This is part of standard diabetes care and is frequently skipped.
  • Adults over 40, periodically — glaucoma risk rises with age.
  • Anyone with a parent or sibling who has glaucoma, whose own risk is substantially higher. People of African ancestry develop glaucoma earlier and more severely, so this matters particularly in South Africa.
  • Children, before starting school. A child does not know their vision is not normal and will not report it; it shows up as struggling at school.
  • Anyone with high blood pressure, which damages the small vessels in the retina too.
  • Anyone whose vision has changed, at any age.

Everyday eye care

  • Sunglasses with genuine UV protection. South Africa's UV is extreme, and it contributes to cataracts and to eyelid cancers. Dark lenses without UV filtering are worse than none, because the pupil opens wider.
  • Wear eye protection for grinding, welding, hammering, wire brushing and strimming. Most serious eye injuries here are preventable and happen at work or in a yard.
  • Screen use does not damage eyes, but it does dry them because blinking drops. Look away regularly and blink deliberately.
  • Stop smoking — it raises the risk of both cataracts and macular degeneration.
  • Control blood sugar and blood pressure, which protects the retina more than anything applied to the eye itself.
  • Never buy or share prescription eye drops, particularly steroid drops, which can raise eye pressure and cause glaucoma when used unsupervised.

Symptoms that need same-day care

For a chemical splash, rinse first and rinse for longer than feels necessary — what happens in the first minutes decides the outcome more than anything done at hospital.

Common questions

Does reading in poor light damage your eyes?
No. It causes eye strain and tiredness but no lasting damage. The same is true of sitting close to a screen or television.
Are cheap reading glasses from a shop harmful?
They are not harmful, and for straightforward age-related reading difficulty they are often adequate. What they do not do is check the health of the eye — so they are a convenience, not a substitute for having your eyes examined.
I have diabetes but my vision is fine. Do I still need a retinal check?
Yes, and that is exactly the point. Diabetic retinopathy causes no symptoms until it is advanced, and by the time vision changes the damage is largely permanent. The check is what catches it while treatment still works.

Sources

Last reviewed 4 August 2026.