Photochromic lenses are eyeglass lenses that are almost clear when worn indoors and darken automatically on exposure to the sunlight. The molecules that cause photochromic lenses to darken are stimulated by UV rays from sun. On exposure to ultraviolet light, the lenses darken to mimic sunglasses. These changes in lens optimise the eyesight. The lenses do not darken in artificial indoor light because it happens only in response to the short wavelengths of sunlight.
Photochromic lenses are considered to be helpful due to following reasons:
- You do not have to carry both pairs of glasses every time you go out, your prescription glasses and sunglasses, as these glasses suffice both needs.
- The probability of losing glasses is almost negligible as you do not have to juggle between both the glasses.
- As the lenses adapt automatically to external light, it causes lesser strain on eyes as the degree of darkening depends on the amount of light. Since the lenses change rapidly, the glare can be reduced by regulating the amount of natural light you are exposed to. Hence, you will feel maximum comfort whatever be the amount of light exposure.
- Best of the photochromic lenses work very fast on darkening and returning to clear lenses within few seconds only.
- Your eyes are protected round the clock, as the lenses protect the eye from harmful UV rays; hence, light sensitivity is also reduced. The level of protection adjusts itself depending on the needs of your eyes.
- These glasses are available in most lightweight lens materials and can be used in all forms of lenses, be it single, bifocal or progressive lenses.
- The vision becomes crisper and colours appear better in sunlight.
On the other hand, there are few things you should consider before buying these glasses:
- A recent research suggests that spending quality time in natural light reduces the chances of near-sightedness.
- In addition, spending around 3 hours daily in sunlight stimulates dopamine and helps in regulating eyeball growth.
- It is also important for elders to be exposed to natural light, as it helps in fighting against cataract and developing healthy natural biorhythms.
- These glasses do not work in cars, as UV rays are blocked by the windshield and, hence, darkening mechanism cannot be initiated.
Hence, it is necessary to weigh the pros and cons before investing in these lenses.It should meet your needs and solve the purpose for which you are planning to buy these glasses.