Sunlight Will Damage your Eyes
Sunlight Will Damage your Eyes
Sunglasses Protect your Vision!
Sunglasses fundamentally, are intended to limit the amount of light that passes to the eye. Advanced Lenses also reduce the amount of glare entering the eye. Sunglasses essentially limit the discomfort caused by bright sunlight and glare. Unfortunately, limiting bright sunlight does not protect your eyes from damage unless your sunglasses are designed to limit the effects of Ultra Violet Radiation and Blue Light. Sunglasses lens color can be a very important factor in preventing damage caused UV and Blue Light. In order to understand lens color selection we should start by taking a quick look at the eye and it's parts.
Most of us know how a camera operates, but the eye is probably a mystery to us. The eye functionally is very similar to a digital camera. The eye is made up of several important parts. The Cornea is a protective covering which protects the front of the eye. This would be similar to the protective coating on a camera lens which protects against scratches. The Pupil is the dark area of the eye. It adjusts to let more or less light into the eye. This is similar to the electronic control on a camera that regulates the amount of light entering the lens. In the extreme, not enough light, the flash is fired to add light to the subject, too much and the lens is blocked reducing the amount of light entering the camera. The lens of the eye is clear tissue that focuses light onto the Retina, just like the lens in your camera. The Iris determines your eye color, similar to a lens filter. Your eye color determines how much light is passe to the Retina. Blue Eyes pass more light than brown. The Retina of the eye senses light and passes information to the brain via the Optic Nerve, almost like the CCD detector of your camera, where light is converted to an image. And now we come to the Macula of the Eye which determines the level of details that we see. This is equivalent to the pixel resolution of the camera.(more pixels, clearer pictures)
Ok, now we have a rudimentary idea of how the eye operates. Now we also know that excessive exposure to the sun can cause skin damage and cancer. The eyes are also damaged just like the skin. This damage is caused by components of light named UVA and UVB (Ultraviolet Components) Neither are visible to the eye but both are damaging. UVA has a higher frequency(cycles per second) then visible light, and UVB is higher in frequency then UVA. Excessive UV radiation causes DNA damage.
Most of us know that exposure to UV radiation is dangerous but now their is evidence that blue light is also damaging. Blue Light is not Ultra Violet. Blue Light is the high energy portion of the visible spectrum. We can see blue light unlike UV light which is invisible. Blue light has the ability to penetrate the tissue and cause cellular damage.
Fair skinned, blue eyed people are at greater risk to sunlight damage than dark eyed people with dark skin. Melanin is the substance that gives eyes their color. Blue Eyes have less then Dark Eyes so more light passes to the Retina which subjects people with lighter eye color to more eye damage from sunlight, especially blue light.
So, a good pair of sunglasses should reduce the discomfort of bright sunlight, eliminate glare, and reduce the cellular damage caused by UVA, UVB and Blue Light. Consider all this when buying a pair!
