I have experienced some great September weather. Sunshine, blue skies and reasonable temperatures at this time of the year are referred to as an Indian Summer and I love it.
Getting outside helps with vitamin D replenishment in the skin, well-being and reducing the chances (probably) of myopia development and/or progression. However, there is a downside. Long-term exposure to UV (ultraviolet) light has been linked to the development of cataract, pterygium and basal cell carcinoma, and exposure to blue light (the short-wavelength part of the natural light spectrum) has been linked to the development of age-related macular degeneration. Low levels of blue light transmission have a cumulative negative effect on the retina by the time a person gets to their 60th, 70th or 80th decade.
Adults have some natural protection from blue light through the yellow filter that develops in the crystalline lens. Ironically, this yellowing could be caused by incident UV. Adults have further protection through a yellow pigment that may develop in the macula. I say may because the formation of this pigment is diet-dependent and it needs constant replenishing. More on that in another ETJ item.
The problem is that children do not have much if any, yellow filter in the crystalline lens (see figure). While average macular pigment levels in 4-16-year-olds are similar to average adult values (see figure for the work of one of my doctoral students), we do not know how much macular pigment there is in 2-3-year-olds.
When I was sat in a children’s play area (I have two children so this is allowed) during the recent Indian Summer, I noticed two children wearing sunglasses. I noticed this because it is a rare thing. Their parents and grandparents were also wearing sunglasses. This is less rare. My first thought was that one of the adults was an eye specialist. My second thought was to look around the play area and count the children. There were 18 and only the aforementioned two were wearing sunglasses; around 11%. The majority of the children in the play area were 2-3-year-olds. I then counted the adults. There were 29 and eight were wearing sunglasses; around 28%.
You might be thinking that my survey was biased by the ‘sunglasses family’, but my figures are similar to those from a survey conducted in Hawaii, of a great many more people, where adults (41.6%) were more likely to wear sunglasses than children (12.3%). The survey was conducted in high sunshine areas, such as beaches, pools and parks so it is surprising that the uptake of sunglasses was so low, considering how bright it must have been.
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 UV and blue light and to the protective effects of sunglasses. We must get better at promoting the wearing of sunglasses in settings with risk for UV and blue radiation exposure, especially by children. It is an important public health message that is not getting through.