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So many patients have asked me the following question:  Will a pair of cheap sunglasses damage my eyes?  Is it worth it to spend lots of money on a proper pair of sunglasses?  What does proper sunglasses actually mean???

Let’s start by asking why we should be wearing sunglasses.  A lot of us spend quite some time of our summer days outdoors.  This means we get exposed to UV rays of the sun.  Now UV exposure is one of the main causes of ocular problems.  Some of these ocular problems include the growth of a cataract, which is a loss of the transparancy in the lens of the eye, and a pterigium, which is a growth on the conjunctiva.  Photokeratitis and cancer of the eye may also be the result of overexposure to UV radiation.  The main purpose of sunglasses must therefore be to protect the eyes from UV radiation.

So why should we be using “proper” sunglasses?  Why not just a “cheapie”? Both makes your eyes feel more “protected” against bright light? Here is the answer.  Naturally, when our eyes are exposed to sunlight, the pupil constricts to minimise the amount of light entering the eyes.  Thus it also causes less exposure to harmful UV rays.  At night time, the opposite happens.  The pupils dilate (enlarge) to maximise the amount of light into the eyes and help us see better in low light conditions.  When we wear sunglasses in daytime, the light conditions behind the sunglasses are darker due to the dark tint of the lenses, so the pupils tend to dilate.  The problem now is that the natural protection mechanism of the constricting pupil does not work well and more light, including UV rays, enter the eyes.  That is why wearing cheap sunglasses without UV protection is actually worse than not wearing any sunglasses at all!  Proper sunglasses have UV protection against UVA, UVB, UVC and dangerous blue light.  It therefore prevents UV rays to enter the eyes.

Other benefits of a proper pair of sunglasses includes the following:  It provides protection from intense light.  When the eye receives too much light, it naturally constricts the pupil (as explained before). Once it has constricted the pupil as much as possible, the next step is squinting, which causes discomfort.  A good pair of sunglasses can block light entering the eyes by as much as 97 percent, providing much more comfortable, relaxed vision.  Sunglasses then also provide protection against glare. Certain surfaces, such as water, can reflect a great deal of light, and the bright spots can be distracting or can even hide objects. Good sunglasses can completely eliminate this kind of glare using polarization.  Certain frequencies of light can also blur your vision, where others can enhance contrast. Choosing the right color, and considering the option of polarisation for your sunglasses, is therefore important for the purpose you want to use your sunglasses for.

* eugenie@ecoptom.co.za

* www.optometristspretoria.co.za

* 012 548 0131