Enjoying the African sun is one of the great joys of living in South Africa. Time outdoors comes with countless benefits — from boosting your mood to encouraging an active lifestyle. But sunshine can have a downside, especially when it comes to your eye health. Did you know you can actually sunburn your eyes? Not quite in the way it happens to your skin, but the sun’s radiation can cause harmful changes to the delicate structures responsible for keeping your vision clear.
The Real Culprit – UV Radiation
The main culprit behind sun-related eye damage is ultraviolet (UV) radiation. Light is made up of both visible and invisible wavelengths, arranged along a rainbow-coloured continuum called the electromagnetic spectrum. The visible light we see every day falls roughly between 400–700 nanometres (nm). Beyond that, with longer wavelengths, is infrared light (>700 nm) — the warmth you feel from the sun. On the opposite, shorter wavelength end is ultraviolet (UV) light (<400 nm), which we cannot see but which can be particularly harmful to the eyes.
While other wavelengths may also contribute to certain eye conditions, UV light is well known for its damaging effects. It can trigger changes at a cellular level, accelerate ageing in eye tissues, and increase the risk of disease — making it an important environmental hazard for eye health.
Your Eyes’ Natural Defences – And Their Limits
A recent study found that the cornea absorbs about 63% of UV rays, and together with the lens, these structures block over 99% of UV light from reaching the deeper parts of the eye (Fukuoka et al., 2023). These protective layers act like natural filters, but in doing so, they take the brunt of the damage. Over time, oxidative stress builds up, contributing to the changes we see in eye disease.
In fact, it’s estimated that up to 20% of cataracts worldwide are linked to UV exposure. Other solar-related eye conditions include corneal sunburn (photokeratitis), conjunctival growths such as a pterygium, and skin cancers of the eyelids. Light exposure is also suspected of worsening certain types of macular degeneration. With climate change and ozone depletion leading to higher UV levels, this risk is expected to rise. The World Health Organisation has classified UV radiation as an “environmental carcinogen” — a reminder of the danger sunlight can be.
This then leads to the question…
How to Protect Your Eyes?
A big part of protecting your eyes from UV damage is making small, consistent habit changes. Wearing a broad-brimmed hat and appropriate clothing can significantly reduce exposure. Eye protection is equally important — such as UV-protective sunglasses or contact lenses. Being aware of your surroundings and choosing the timing of your outdoor activities wisely also helps. UV levels peak during midday and early afternoon, and exposure increases at higher altitudes. Reflective surfaces such as water, snow, and sand can amplify UV exposure. And remember — clouds do not block UV rays, so even overcast or wintry days can still put your eyes at risk.
Choose Your Sunglasses Wisely
When choosing sunglasses, look for the label “UV400 protection” / 100% UV rating. This means the lenses block both UVA and UVB rays, offering full protection against harmful UV light. A common misconception is that the most protective sunglasses are the most expensive — but cost is often influenced by branding, style, lens quality, and whether they’re polarised. Polarised lenses reduce glare from reflective surfaces – making them great for driving or outdoor activities. However, polarisation does not block UV light, and thus your eyes can still be exposed.
A Quick Side Note on Vitamin D
I’m often asked about Vitamin D and whether avoiding the sun might cause a deficiency. Most doctors recommend getting Vitamin D through a safe oral supplement rather than unprotected sun exposure. If you’re concerned about your levels, we can easily check this with a simple blood test and prescribe the right dosage if needed. When it comes to your eye health — and your skin — limiting time in the harsh African sun is still the safer choice.
The Bottom Line – Prevention!
Prevention is key, and protecting your eyes from the sun is essential for your overall health and wellness. Incorporating simple habits, such as wearing a hat and the right pair of sunglasses, can make all the difference!
