When your fingerprints are all over the lens of your camera, the pictures you take won’t be as sharp as expected. You won’t let this happen to your eyes, I guess. Nevertheless, the lens of your eye can become hazy for other reasons. One of them is the fine weather.
Ageing is the main reason for the clouding of the lens, but excessive UV radiation of a clear blue sky is another major contributor. The World Health Organization estimates that cataracts account for almost 15 million blind people worldwide. About 20%, or 3 million, of these are most likely caused by UV radiation.
The lens is not solid. It is a capsule filled with water and protein fibres. The protein fibres are normally crystal clear but can ‘wear out’ with age. They can become opaque, similar to how an egg white clouds when it gets cooked. Other factors, such as UV radiation, can alter the protein prematurely.
Cataract development is very variable amongst individuals. The process is generally slow and initially may affect only part of the lens. In one person it develops from the lens’s rim and grows inside, in another person’s eye the lens begins to cloud from the centre. Curiously, when the centre is lightly clouded, the person may temporarily improve the ability to see close objects. In any case, the growing cataract will eventually severely impair vision and frequently lead to blindness.
In the early stages, a cataract is merely a nuisance. But soon extra lighting, different eyeglasses and protection from glare is needed. UV radiation protection and less alcohol and nicotine should help to slow the process. Some swear on the effectiveness of alternative supplements and diets.
Once the cataract interferes too much with the daily life, surgery should be considered. Eye surgeons replace millions of cloudy lenses with substitutes every year, and this safe procedure returns better vision to as much as 90% of patients.
Sunlight helps to grow many useful things in nature but sun also has to take the blame for some rather useless growth on your eyeballs. When someone tries to convince you again that everything in life has its purpose, point to either corner of your eye and ask the smart person, ‘What purpose has this fatty, fleshy growth then?’
Pterygium and pingueculum are the names for common but harmless yellow-white growths. Both are almost identical in appearance and usually begin their lives on the nasal side of the eyes. They slowly grow towards the centre, but only pterygium may encroach onto the cornea and cause vision problems.
Because UV radiation is a major factor, the disorder occurs mostly in populations of ‘sun-drenched’ countries. Heat, wind and airborne irritants can inflame the growth. Anti-inflammatory eye drops reduce the redness and itching. Otherwise, treatment is not necessary unless the growth affects vision or is cosmetically undesirable.
The eyes aren’t immune against cancer. Squamous and basal cell cancer often develop on the sun-exposed parts such as the cornea and the eyelids. As previously mentioned, body parts perpendicular to the sun’s rays are most at risk of UV radiation damage, so therefore the lower eyelid margin suffers most. Symptoms and treatment are similar to skin cancer.
A malignant melanoma can start its destructive live on about every part of the eye. It can even hide behind the skin of the retina. Sunlight is again a prominent risk factor, especially overexposure to it in early life. It comes as no surprise that populations in countries with high UV radiation levels have most victims.