The effects of sunlight on our eyes – May

with Stephen Evans

Stephen Evans has been an optometrist in Swansea for the past 32 years.

Here he offers TheBAY readers some advice on caring for your eyes this summer

The effects of sunlight on our eyes


I hope this article will help you understand a little bit more about your eyes, to dispel some of those myths and popular fallacies, to give you some easy tips about looking after your own eyes and finally to show you that there is much more to visiting your optometrist than just buying glasses and contact lenses.

With spring upon us and the exciting prospect of some much welcomed sunshine ahead I thought it would be good to write an article about enjoying the sunshine without letting it damage your eyes.

You’re probably thinking that surely we don’t get enough sun in Wales to damage our eyes?

It’s true that South Wales may not be as sunny as New South Wales but over a lifetime that may include some nice sunny holidays, the effects of sunlight on our eyes will stead-ily accumulate. If you also enjoy water or snow sports you will be exposed to even more of the sun’s damaging ultra violet light (UV). You generally don’t feel UV rays so there is no natural warning that damage is being done. Eye damage from the sun can happen in one day or gradually over a lifetime but repeated exposure to bright sunlight without adequate protection can damage the eyes and their lids. Although clouds reduce the level of UV reaching your eyes, clouds don’t block UV completely, which means your eyes can be exposed to UV rays even on overcast days.

Who is most at risk for eye damage by UV light?

Young people. Because the lenses in their eyes are clearer children’s eyes are much much more susceptible to UV exposure. The World Health Organisation estimates that up to 80% of a person’s lifetime exposure to UV light will occur before the age of 18. Under-12s are particularly sus-ceptible because the clear lenses in their eyes allow the UV light to pass through more easily. Very young children younger than six months should be kept out of direct sunlight altogether.

People who spend a considerable amount of time outdoors especially those who enjoy snow and water sports. Many surfaces but especially water and snow will reflect the sun’s UV light up into our eyes which can increase our exposure to UV light by as much as 80%.

Patients who have had cataract surgery.

Individuals who have retinal disorders.

People who are more sensitive to UV rays, including those taking certain medications, such as tetracycline, sulpha drugs, birth control pills, diuretics and tranquillisers.

What effect can sunlight have on your eyes?

Although the eyelid is designed to protect the eye, its skin is exceedingly thin and contains fragile tissues that may be injured by UV light. The cornea, the window to your eye and the natural lens inside your eye, filter UV rays, but by doing so for many years, they may become damaged. This is especially true for the lens, which through years of UV absorption slowly turns yellow and eventually may develop cataracts.

Eyelid cancers. Skin cancers of the eyelid, including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) as well as melanoma, account for 5 to 10 per cent of all skin cancers. Most occur on the lower lid, which receives the most sun exposure. Both of these types of cancer are found mainly in patients with a history of sun exposure. When diagnosed and treated early, eyelid cancers usually respond well to surgery and follow-up care.

Watch for these early warning signs:

A lump or bump that frequently bleeds or does not disappear.

Persistent red eye or inflammation of the eyelids that does not respond to medication.

Newly acquired flat or raised pigmented lesions that have irregular borders and growth.

Unexplained loss of eyelashes.

If you have any of these warning signals you should consult your doctor or optometrist straight away.

Cataracts. Cataract is a progressive clouding and yellowing of the eye’s natural crystal-line lens. Too much exposure to sunlight can cause these to form at a younger age.

Macular degeneration. The macula is the central part of your retina which allows you to see detail and colour. Often referred to as age-related macular degeneration, some studies have suggested that this can be exacerbated by UV light.

Photo-Keratitis or corneal sunburn can be caused by excessive exposure to UV light from the sun or tanning machines which can literally burn the cornea. This kind of damage is most likely to occur in extremely bright conditions especially when near snow or water or at altitude.

Pterygia are non-cancerous growths that can occur in one or both eyes. Sometimes called “surfer’s eye,” this condition results when sun damages the conjunctiva which is the thin membrane covering the surface of the eye and the inside of the eyelids. It is a triangular-shaped growth which starts on the white part of the eye but in more ad-vanced stages the tip of the triangle can grow across the cornea. The problem comes from a combination of UV light exposure, wind, and abrasion from dust or sand.

How can you protect your eyes from UV damage?

You can greatly reduce your eyes exposure to UV light by wearing good quality UV absorbing sunglasses and a wide-brimmed hat or cap and by applying sunscreen as normal.

What should you look for when purchasing sunglasses?

There are many different types of sunglass lenses and confusing claims made by the manufacturers. Some sunglasses are more suited to certain needs than others so here is a simple guide to some of the terminology associated with sunglasses. If you need more information I would recommend you seek the advice of your optometrist who will be able to help you make the right choice for your particular needs.

CE mark. All sunglasses should be marked with the European CE mark to guarantee their protection against UV light.

Polarised lenses cut reflected glare that bounces off smooth surfaces like water, snow or pavements. This can make things clearer to see but polarisation alone does not increase UV absorption.

Mirror finishes are thin layers of various metallic coatings on an ordinary lens. Although they do reduce the amount of visible light entering your eyes, do not assume they alone will fully protect you against UV radiation.

Wraparound glasses are shaped to keep the light from shining around the frames and into your eyes.

Gradient lenses are generally shaded from dark at the top to light at the bottom. They may be useful for driving because they don’t dim your view of the dashboard, but they’re not as good on snow or at the beach.

Photochromic lenses darken and lighten depending on how much UV light they are exposed to. They will go very dark at altitude or in snow but may not go so dark behind the windscreen of a car.

Impact resistance. This varies greatly depending on the lens material. For driving or if you participate in sports such as skiing or cycling it is important to select a sunglass with high impact resistance.

Lens darkness – A medium lens is good for day-to-day wear, but if you use the glasses for very bright conditions choose a darker lens. But remember the colour and the degree of darkness do not tell you anything about the lens’ ability to block UV light.


While parents are well-versed at protecting youngster’s skin from sunburn, it appears that there is little awareness for the protection of their children’s eyes from harmful sunlight. A survey commissioned by the College of Optometrists found that 76% of parents don’t protect their children’s eyes in the sun. While almost half (43%) of parents ensure their child’s time in the sun is limited and three-quarters (76%) make sure they apply sun cream to their child’s skin, buying sunglasses to provide protection for the eyes appears not to be a priority. Almost a third (29%) of those questioned do not buy sunglasses for their children; however, of those who do, only one-in-four (25%) choose sunglasses from a reputable brand or supplier and 46% opt for price over protection. At present many schools insist on hats and sun-screen in the playground but stop children bringing sunglasses to school, seeing them as fashion accessories that will only cause problems when lost but please remember that if you think you need to apply sunscreen to your children they really also need to be wearing sunglasses.

Make sure your children’s eyes are protected from the sun with good quality sunglasses. Children who wear spectacles all of the time will benefit from a second pair of prescription sunglasses.

As well as direct sunlight you can get this much more UV too:

25% more from white water reflection

50% UVB and 80% UVA passes through the upper 50cm of water

20% from sand and grass reflection – and 40% when wet 85% increase from snow reflection 100% increase at 3000m altitude

80% of UV rays pass through cloud

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