There is a reason why professional skiers wear protective goggles, and why even beginners are asked to wear some type of eyewear. For one, the ultraviolet light reflected from the snow can lead to sunburn of the cornea. Furthermore, intense reflected light makes it difficult to see the snow-covered surface ahead. This lapse in vision can cause the skier to overlook any bumpy or dangerous terrain ahead. Also, chilly winter air can make the eyes water, which again, makes it exceedingly difficult for a skier to see the path ahead. More importantly, not protecting your eyes against cold air, snow, and bright light can lead to snow blindness. Wearing simple sunglasses or prescription glass does not provide adequate protection for the eyes, which is why, it is imperative that every skier use skiing goggles. This Buzzle guide for buying the right skiing goggle discusses the features to look for, and the purpose served by each of them. Shape of Skiing Lenses Perhaps the most important feature of a goggle is its lens. During your search, you will come across cylindrical (flat) and spherical lens skiing goggles. Flat Lens Goggles Cylindrical lenses are curved along a single axis. Therefore, the lens has a vertically flat structure and is curved horizontally. Although flat lens skiing goggles are comparatively cheaper than spherical lenses, they provide limited peripheral vision. Secondly, its flat edges also tends to reduce optical quality and makes the viewing window to appear distorted, because the lens allows light to pass through it from the top and bottom of the flat vertical axis. Therefore, since the light is not displaced evenly by a flat lens, its surface points cause blind spots and glare. The shape and limited volume/space between the user's face and the flat lens goggle leads to increased fogging. Spherical Lenses On the other hand, spherical lens goggles are curved horizontally as well as vertically. Spherical lenses were designed to mimic the curvature of the eyeball, and therefore, provide excellent peripheral vision and a broadened field of view. The curvature of the lens ensures that light reaches the eye at a uniform angle, which prevents the view from getting distorted. This feature also reduces glare because the curved lens causes much of the light to bounce off its surface. Additionally, the extra space between the user's face and the goggle, helps reduce fogging to a large extent. It is because of these advantages that spherical lenses are more expensive as compared to flat lens ski goggles. VLT and Tint of Lenses Visible Light Transmission (VLT) is the percentage of visible light that passes through the lens. The VLT of a lens is determined by its tint. Darker the tint, the lower the VLT and vice versa, which helps in increasing the contract and visibility of the skier. Each lens color offers variable percentages of VLT that range from 0-100% and are accordingly, supposed to be used on sunny or cloudy days. For instance, a skier who wishes keep most of the light out on a bright day, must go in for darker tints, such as mirrored gray and black lenses, that have lowered VLT ranging between 5-30%. On the other hand, in low visibility conditions, such as a cloudy or foggy day, or while its snowing, skiers must opt for tints that increase visibility. Blue-, yellow-, or rose-tinted lenses have higher VLT percentage ranging between 55-90% and let more light pass through the lens. Amber, brown, gold, and p lenses are suitable for moderate light conditions, such as overcast conditions, and help detect shadows and bumps on the snow. Those looking for lenses that can be worn in all types of light conditions, should consider go in for photochromic lenses that automatically adjust their tint and VLT. Number of Lenses Skiing goggles are available in single as well as double lenses. As a matter of fact, double lens goggles are better and more adept at keeping the goggles from fogging. While a single lens goggle is usually made of plastic or polycarbonate. Although this type of skiing goggle shields your eyes from the outer weather conditions, it does not prevent fogging. On the other hand, double lens goggles are made of polycarbonate lenses. The two lenses are separated by an air barrier and are sealed together on all sides with foam. While the inner lens keeps fog at bay, by moderating the heat from the wearer's face and the cold external temperature, the outer lens protects the eyes from the environment. Therefore, the air barrier creates a thermal cushion that prevents cold air from affecting the user's vision. Mirrored Lenses You will also come across skiing goggles with chrome coated or mirrored lenses, which are excellent for reflecting light, thereby reducing glare to a large extent. Secondly, mirrored lens limit the amount of light that can pass through, thereby making such goggles suitable for being used in bright conditions. Once a lens is mirrored, it can be hard to tell the actual color of the lens, therefore, make sure you wear the goggles to check whether you're buying the right colored lens. UV Protection Make sure you ask the seller for goggles with 100% UV protection. Consider opting for polarized lenses as these provide greater UV protection and reduces glare from the snow and sunlight, which enhancing visibility and contrast even in low light conditions. OTG (Over the Glasses) If you are required to wear prescription glasses, you will need to go in for OTG skiing goggles that are meant to be worn over prescription glasses. These goggles have ample space behind the lens to accommodate glasses, and are thus, comparatively deeper than usual skiing goggles. The goggles have slots on the arms, which are meant for accommodating the arms of the glasses behind them. Make sure that you wear a couple of OTG glasses, and choose one that feels the most comfortable. Frame Size and Fit Not every skiing goggle fits perfectly. For most kids and some adults with small faces, a small framed goggle will do; however, for many, a medium- or large-sized goggle is more suitable. Wear the goggles along with your skiing helmet or cap, to check whether it fits well. Go for a goggle that has a frame that does not pinch or press on any part of your face, and is equipped with an adjustable strap. Ventilation Another important feature that every good skiing goggle must have is vents. These vents are meant for preventing the lenses from fogging up, and therefore, should be worn and tested before purchase. Secondly, wear the helmet along with your goggle to make sure that it is not blocking any of the vents on the goggle. Lastly, go for goggles with foam inserts as these make the goggles more comfortable to wear and block out cold air and moisture. For greater support and comfort, choose goggles that have a thick strap as these will not rub into your skin or leave pressure marks.