Types of lenses used by Ray-Ban
Ray-Ban uses four different types of lenses for its sunglasses. The B15 XLT lens, the G15 XLT lens, the polarized lenses, and the regular lenses, which we won’t discuss here because there is nothing special about them (they just come in different colors).
Lens B15 XLT
Ray-Ban B15 XLT lenses are brown in color, blocking 100% of all UV rays and allowing only 15% of visible light to pass through (that’s an 85% reduction!). These brown lenses also offer a bit more contrast by reducing the amount of blue light, unlike a G15 lens (described in the next paragraph). Blue light is captured very easily by the eye and has the effect of softening other colors that are harder on our vision. In other words, by reducing the amount of blue light, the differences between colors and brightness of objects are more pronounced.
G15 XLT lens
G15 XLT lenses have the same properties as B15 XLT lenses, however they are grayish / greenish in color. The G15 lens is the original aviator lens that the military requested Ray-Ban to develop. The challenge was to design a “neutral color” lens; in other words, a lens that filters light like the human eye does. If you want a lens that offers slightly less contrast between colors, the G15 XLT lens is for you because it offers similar color sensitivity to the human eye. With a lower contrast lens, the difference in color and brightness of objects will be reduced. This means that the colors you see through these lenses will be natural and soft on the eyes.
Both the B15 and G15 XLT lenses are made of impact resistant optical glass that is naturally scratch resistant. The quality and stability are remarkable, and you will notice virtually no color fading over time.
Polarized lens
Polarized lenses essentially reduce the amount of glare produced by reflective surfaces like water or other semi-transparent objects, and even some metal surfaces. Glare refers to the difficulty of seeing in bright light.
Sunlight, for example, bounces off surfaces in all directions (that is, vertically, horizontally, or diagonally). For people who are active in the “horizontal plane”, it means that bright sunlight bouncing horizontally enters the eye in a similar way. This causes the pupils to contract and significantly reduce the contrast. That is why drivers have a hard time seeing the road ahead of them if they drive in very sunny conditions (if the sun is in front of them).
Polarized lenses have a laminated surface with vertical stripes that create a filter, which effectively cuts horizontally polarized light and only allows vertically polarized light to enter. In other words, if you are in a clear lake, you can probably see below the surface or if you are driving, you can now see the road ahead.
Some limitations of polarized lenses are that LCD screens can be distorted or you may notice a “rainbow” effect if your car windows are tinted.
All 3 lenses are very useful, particularly the polarized ones, but expect to pay more for sunglasses.
Lens base
Lens base simply refers to the base curve or front curve of the lens measured in “diopters,” which is a term that only opticians really care about. You will find that many Ray-Ban aviators have a “Lens Base 6”, which basically means that they are sufficiently curved and designed to function as sunglasses (that is, they cover the eyes enough).
Lens size
Lens size is measured in millimeters and refers to the length (or width) of a lens. Please take this into account when making a purchase. Many Ray-Ban models come in different lens sizes. Make sure you get the size that fits your face or you could end up with a pair of aviator glasses that don’t fit you well.
Some Ray-Ban sunglasses have lens sizes that are designated as extra small, small, etc. This is common for models that don’t look like traditional two-lens glasses. These sunglasses have a “single lens” design, where the lenses connect seamlessly through the bridge. For this reason, the traditional size is not applicable. These shades are for a haute couture look.
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