During the three years I've lived in Australia, I've spent a lot of time wearing Sunglasses (or, as they're more commonly known in Australia, Sunnies). Even in the winter here, it's often very bright and sunny (even if the air is cool). In the summer, it gets really bright and sunny. Sunglasses – well, that's what they're for isn't it, wearing in the sunshine?
The more I've found out about Paleo, the more I question other aspects of my life, sunglasses being one such example.
Whilst early examples of sunglasses have been seen as far back at the 12th century, they didn't become common until the early 1900's. That's not even five generations ago. Whilst correlation is certainly not causation, it is interesting to note that 25-35% of people of a European descent have Myopia (short sightedness) today, whereas a study of hunter gather tribes revealed Myopia in just 0.4% of the population (1) As well as diet, could widespread use of sunglasses be responsible for the widespread decline in eyesight?
Some estimates suggest Indigenous Australians have been here for up to 70,000 years, surviving for 69,900 without needing sunglasses? Why are they now they essential for optical health?
Sunlight entering the eyes takes two courses – one for vision, the other goes to the hypothalamus gland. This pathway seems to have a crucial role in the body clock, energy and hormone production (including melatonin). It would make sense for the body to use this pathway to regulate circadian rhythms. Circadian rhythms ensure sleep and wake cycles occur properly, and that the body is in tune with seasonality. Therefore doesn't it stands to reason that wearing sunglasses, and reducing the sunlight entering your eyes, will impact these functions?
This would tie in with anecdotal observations I've heard that when not wearing sunglasses, people get less sunburnt, then when they do wear sunglasses. Perhaps wearing sunglasses also leads to people staying out in the sun for longer than they would without sunglasses?
In the spirit of n=1 self experimentation, I'm going to wean off the sunglasses this summer and see what (if any) impact it has on me. Will my new found improvements in my sleeping patterns improve further still? Will my eyesight improve?
I'll report back in a future post any differences I've noticed.
Do you wear sunglasses? Do you think it is foolish not to wear sunglasses throughout the Australian Summer? I'd love to hear your thoughts in the comments, below!