According to Dr Joseph Michael Mercola, an alternative medicine proponent and osteopathic physician, he approaches this issue the same way he approaches optimization of Vitamin D.
First of all, the number of evidence suggest that sun exposure can also be beneficial to the eyesight, however, intense UV light striking the eyes for longer time periods should be avoided, Dr Mercola said.
Sunlight can actually nourish the eyes. But, for instances such as reflected lights from car windshields or in vehicles on a sunny day, wearing sunglasses can be useful, as Dr C. Stephen Foster, a professor of ophthalmology at Harvard Medical School, mentioned in Time Magazine.
Dr Foster said it is because it is like taking in ultraviolet light in a double dose. “You’re getting the direct exposure from the sun and a second exposure from the reflected light.”
According to him, the rays of the sun are even stronger at higher altitudes, therefore increasing the risk of the attendant eye. “Wearing sunglasses can protect a person’s eyes from all these concerns,” he concluded.
The utmost guide in choosing sunglasses is its capacity to block UVB and UVA rays by 99 to 100 per cent, per Time Magazine. The sunglasses’ colour and shade does not even matter.
Dr Mercola suggested that you’d start considering to avoid wearing sunglasses regularly for another reason. Routinely wearing sunglasses hinders the eyes from absorbing required light that is essential for the body’s circadian rhythm to properly function.
Circadian rhythm is the body’s master clock, and enough amounts of natural light are important for its synchronisation. This master clock is composed of cell groups in the brain known as the suprachiasmatic nuclei, which operates simultaneously as the surrounding’s light-dark cycle.
This group of nuclei is greatly dependent on the light that hits the photoreceptors in the eyes. Other biological clocks in the body also work in synchronisation with the master clock.
For example, when the master clock is ‘off,’ the body will not properly function. “Your mood and sleep, in particular, will tend to suffer, and depression and insomnia may become problems,” Dr Mercola said.
Source: Medical Daily