India receives some of the highest levels of ultraviolet radiation in the world. Nashik, at approximately 600 metres elevation with strong seasonal sun, is no exception. Yet most people choose sunglasses based primarily on how they look — without knowing whether they actually protect the eyes.
This guide explains what UV protection in sunglasses means, what the standards are, and what to look for.
UV Radiation and the Eye
Ultraviolet radiation is electromagnetic energy beyond the violet end of the visible spectrum. The sun produces three types:
- UVA (315–400nm): Penetrates deeply. Associated with long-term damage to the lens of the eye.
- UVB (280–315nm): Partially filtered by the atmosphere, but significant at altitude and on reflective surfaces (water, sand, concrete). Associated with photokeratitis (sunburn of the cornea) and accelerated cataract formation.
- UVC (100–280nm): Almost entirely absorbed by the atmosphere. Not a significant concern at ground level.
The World Health Organization recognises excessive UV exposure as a risk factor for three eye conditions:
Cataracts: Clouding of the eye’s natural lens. UV exposure accelerates the cross-linking of lens proteins that leads to cataract formation. The WHO estimates that up to 20% of cataract cases globally may be attributable to UV radiation exposure.
Pterygium: A growth of the conjunctiva (the clear tissue covering the white of the eye) that can extend onto the cornea, causing discomfort, altered vision, and in severe cases requiring surgical removal. It is significantly more common in populations with high lifetime UV exposure.
Macular Degeneration: Cumulative UV exposure is considered a contributing risk factor for age-related macular degeneration, the leading cause of vision loss in adults over 60 in many countries.
The Critical Point: Darkness ≠ Protection
This is the most important thing to understand about sunglasses.
Dark or tinted lenses without UV filtering do not protect the eyes — they make things worse. Here is why: when you wear dark lenses, your pupil dilates because the light reaching it is reduced. If those lenses do not block UV radiation, more UV than normal actually reaches the retina and lens — because the pupil is larger than it would be in bright sunlight without glasses.
UV protection in sunglass lenses comes from a chemical coating or treatment applied to the lens material — not from the darkness of the tint. A lightly tinted lens with UV400 coating provides better UV protection than a very dark lens without it.
What to Look For: UV400
The standard to look for is UV400, which means the lens blocks all ultraviolet radiation with wavelengths up to 400 nanometres — covering both UVA and UVB completely.
This is the standard adopted by the Bureau of Indian Standards (BIS) for sunglasses sold in India (IS 8540), the European CE standard, and the American National Standards Institute (ANSI Z80.3). Reputable sunglasses from established brands will carry this marking.
When buying sunglasses, look for an explicit label: “UV400” or “100% UV protection.” Be sceptical of unlabelled lenses, regardless of how dark they are.
What Polarisation Does (and Doesn’t Do)
Polarisation and UV protection are separate features that are often confused.
Polarised lenses filter horizontally reflected glare — the light that bounces off flat surfaces like roads, water, and car bonnets. This makes vision clearer and more comfortable in bright conditions. Polarised lenses are especially useful when driving and outdoors near reflective surfaces.
However, polarisation does not by itself provide UV protection. A lens can be polarised without being UV-protective, and UV-protective without being polarised. Quality polarised sunglasses from reputable brands typically include both — but the UV400 label should still be present and verified.
Lens Colour
Lens colour affects contrast and how you perceive different light conditions — it does not determine UV protection. A few practical notes:
- Grey lenses reduce overall brightness without distorting colours. Good for driving and general outdoor use.
- Brown/amber lenses enhance contrast, particularly in variable light. Popular for sports and outdoor activities.
- Green lenses provide good colour accuracy with moderate contrast enhancement.
- Yellow lenses enhance contrast in low-light conditions but are not suitable for bright sun.
Any of these colours can carry UV400 protection. Choose based on comfort and use case.
Children and UV Protection
Children’s eyes are more susceptible to UV damage than adult eyes — the crystalline lens is clearer in children and transmits more UV to the retina. Children also spend more time outdoors. The American Academy of Ophthalmology recommends UV-protective eyewear for children whenever they are outdoors in bright sunlight.
A Practical Checklist
When buying sunglasses:
- Look for the UV400 label — it should be explicit, not implied
- Buy from established optical retailers or brand stockists where lens credentials can be verified
- Ensure the frames fit well and wrap close enough to the face to prevent UV from entering at the sides
- For children, prioritise UV protection above style
At Deshpande’s Optiview, all sunglasses we stock carry UV400 certification. Our team is happy to help you choose the right lens for your use case — walk in at any of our four Nashik branches.
References: World Health Organization — Solar Ultraviolet Radiation: Global Burden of Disease. | Prevent Blindness America — UV Eye Safety. | Bureau of Indian Standards IS 8540 — Sunglasses for general use. | American Academy of Ophthalmology — Ultraviolet Radiation and the Eye.