Welcome to question of the day #78

Eyetools question of the day #78

Having just returned from a trip to the south of Europe, I’ve been reminded how hot parts of that continent can get. The heat is derived from sunshine and more specifically the infra-red element of sunshine. Heat makes us uncomfortable but at the other end of the spectrum comes something more damaging; blue light and ultraviolet light (UV).

What I noticed while taking part in the activities available on most Mediterranean beaches was that while some adults were wearing sunglasses very few children were. Even my own removed theirs’ whilst swimming. This is not good. Adults have some yellowing of the crystalline lens and the older they are the more yellowing of the lens there is. This yellowing is part of the cataract formation process and is a result of UV exposure over a period of 50 to 80 years. Yellowing of the crystalline lens helps protect the retina from blue light damage. Not only do most children not wear sunglasses (in my experience and from findings presented in research articles) but they do not have much or any crystalline lens yellowing.

UV is thought to be the root cause of pterygium, basal cell carcinoma, and cataract formation and to have a role in the development of age-related macular degeneration. Some readers might be surprised about the latter since only about 1-2% of incident UV is transmitted to the retina. However, radiation with short wavelengths (blue light and UV) has great potency to cause retinal damage over long periods of time. Low levels of transmission have a cumulative negative effect on the retina by the time a person gets to their 60th, 70th or 80th decade.

The best way to protect the external and internal structures of the eye from UV and blue light damage is by wearing sunglasses on sunny days. This is particularly important when UV light levels are high and the environment is full of light reflective surfaces such as sand and water. Eye specialists are ideally placed to alert parents to the ocular potency of blue light and UV and to the protective effects of sunglasses.