When investing in a pair of sunglasses, there are many factors to consider in ensuring that you are making the right purchase. Looks do count, it's obvious, but there's more to sunglasses than what first meets the eye.

UVA, UVB and Polarised are the most common terms you will encounter when sunglass shopping and although they seem impressive and experts agree that you cannot go without them, we wanted to take a closer look at what exactly makes it sound.

Let's first look at rays.

Our skin and eyes are exposed to the sun's ultraviolet (UV) rays every time we step outside. The UV Index is used internationally to determine the sun's potential to damage your skin and eyes and cause various cancers. Your sunglasses MUST protect your eyes from UV light.

From the perspective of our eyes, UV differs in the following ways:

UVA rays are the most extended type of UV rays. They can penetrate past your eye's cornea reaching the part of your retina that assists with clear vision. Over time, eyes can develop cataracts or macular degeneration if exposed to higher UVA rays. It can also cause sunspots, skin cancer, premature ageing and wrinkles.

UVB rays do not penetrate as deeply as UVA rays meaning that your cornea absorbs nearly 100% of them. It can cause a cornea-confined type of eye disease like pinguecula, pterygium, and photokeratitis. UVB is the sun-stimulating rays responsible for tanning but also sunburn, skin discolouration, skin cancers, and wrinkles.

With adequate lens protection, your sunglasses can prevent the following eye disease:

• Photokeratitis – often referred to as eye sunburn or snow blindness, is accompanied by symptoms such as burning, tearing, redness, blurry vision, grittiness, swelling, light sensitivity and temporary loss of sight.
• Cataracts – cloud the eye lenses, resulting in blurred vision. Although most cases are age-related, UV exposure can also cause cataracts.
• Macular degeneration – the part of your retina responsible for central vision and processing sharp images like facial expressions or text deteriorates due to UV exposure. It results in an inability to see finer details and leaves a somewhat warped or blurred vision.
• Pinguecula and pterygium – also known as surfer's eyes are yellow-coloured growths in the membrane that covers the eye surface. Over time, these may become larger and impair vision. They are very uncomfortable and leave the eyes feeling gritty.