Photochromatic lenses, also known as transition lenses, are eyeglasses lenses that change color based on the amount of light they are exposed to. In bright sunlight, the lenses darken to protect the eyes from harmful UV rays and glare. When the light decreases, such as when going inside a building, the lenses lighten back up to their clear state.
How photochromatic lenses works
These lenses use a special type of material, typically made from nanoparticles of silver halide or organic dyes that reacts to light and changes the tint of the lenses. They are particularly useful for people who wear eyeglasses all the time, as they eliminate the need to switch between clear and prescription sunglasses.
Advantages of photochromatic lenses
Photochromatic absorb UV light and protect eyes
Photochromatic can be used in both indoor and outdoor, whereas sunglasses are only meant for outdoor conditions
They are available in different type of lens designs (single vision, bifocal and progressive)
Another advantage of photochromatic lenses is that they provide a more natural and smooth transition between light and dark. Traditional prescription sunglasses often require a noticeable adjustment period when switching from bright light to low light, but photochromatic lenses adjust quickly and seamlessly.
Disadvantages of photochromatic lenses
Photochromatic lenses don’t adjust rapidly, require 5-10 mins.
Photochromatic lenses will not darken when worn inside vehicles because wind screen glass absorbs virtually 100% of UV light
Photochromatic lens can’t replace sunglasses
Photochromatic lenses are not effective in hot climates
Availability
Photochromatic lenses are also available in a variety of tints and materials, including polarized options that can further reduce glare. However, it is important to note that photochromatic lenses can be more expensive than regular prescription eyeglasses.
Conclusion
In conclusion, photochromatic lenses are a convenient and practical solution for those who need both clear vision and protection from the sun. They offer the best of both worlds, eliminating the need to constantly switch between clear and prescription sunglasses, and provide a more natural and seamless transition between light and dark.
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Lecturer (Nethradhama School of Optometry)
Moptom