Rumor has it that sunglasses are good for your eyes and sunglasses are bad for your eyes. We spoke with Ophthalmologist Tongalp Tezel, MD to separate fact from fiction when it comes to protecting your eyes from the sun.
The sun is a source of ultraviolet (UV) radiation. When you are outside in the sun, you are exposed to two types of UV rays: UVA and UVB.
Both UVA and UVB rays can penetrate and change the cell structure of your skin and eyes, causing burns and injuries, putting you at risk for skin cancer and eye diseases that can lead to permanent vision loss.
The harmful effects of UVA and UVB on the eyes include:
A cataract is an opacity of the lens in the eye. The lens deflects incoming light rays and focuses them on the retina. Human lenses must be clear to transmit light without any dispersion or loss. The lenses gradually become cloudy after age 30, and around age 60 and 70 cloudiness decreases the amount of light entering the eye and scatters incoming light. For this reason, people with cataracts have weak and blurred vision. Aging is the most common cause of cataracts, but UVB rays accelerate cataract formation. In people exposed to UVB for a long time, lens opacities usually develop in the parts exposed to direct sunlight. It is estimated that cataract formation can be reduced by around 5% with proper UV protection.
Exposure to high levels of sunlight can increase the risk of age-related macular degeneration, an eye disease that can lead to loss of central vision, nearly three times.
Eyelid tumors such as basal cell carcinoma and squamous cell carcinoma, as well as intraocular tumors such as uveal melanoma, are associated with greater UV exposure.
Corneal and conjunctiva damage
Basically, a sunburn on the cells in the front of the eye, and it’s painful. In many cases of photokeratitis (damage to the cornea) and photoconjunctivitis (damage to the thin layer of tissue covering the eye), these eye lesions usually heal on their own if you avoid the sun completely for a week. And you can reduce the risk of sun-related eye damage with proper sunglasses.
Are sunglasses good for your eyes?
Sunglasses are healthy if the lenses block UV and the sunglasses are worn correctly (with the nose bridge of the frame touching your face).
The eyes filter out most UV rays, but not all. Anything that limits UV eye exposure mitigates the risk. Sunglasses protect your eyes and can also protect the skin around the eyes.
Can wearing sunglasses damage your eyes?
Sunglasses are bad for your eyes if used improperly or if they don’t block UV.
The eyes adjust to ambient light and the pupils dilate when the light is dim or when you are wearing dark sunglasses. This creates a larger area for UV to access the eye. If the lenses are just colored and don’t block UV, you’re putting yourself at risk of eye damage.
What are the best sunglasses for your eyes?
The ones you wear correctly, adjusted to your face. If you create space between the frames and the eyes by pulling your glasses forward, for example, and you don’t cover all of your eyes, you’re completely at the mercy of the sun’s UV rays.
- Expensive glasses do not guarantee better UV protection.
- Larger frames may provide more coverage, but people with larger frames often drag the glasses down their nose because they feel their eyes are covered too much.
- Small sunglasses are a public health hazard. John Lennon’s height is small.
- Wrapped shapes are the best. About 20% of UV enters the eye from reflected light from the side: wrap-around designs or side shields are recommended, especially with darker tints.
- Anti-reflective coatings can increase UV exposure by causing UV rays to reflect back into the eye.
- There are no sunglasses that are too dark. However, dark lenses can be harmful if they do not offer good UV protection or if UV rays reach the eye from the sides.
Not all lenses claiming to absorb 100% UV can block all UV wavelengths. In the United States, manufacturers are allowed to claim 100% UV protection for lenses that absorb ultraviolet rays with wavelengths up to 380 nm, even though the range of ultraviolet rays extends up to at 400nm.
Make sure your sunglasses can block all UV rays up to 400nm. This becomes a significant problem for the protection of the retina in children since their lenses are more transparent to UV than those of adults.
Do contact lenses offer UV protection?
Soft UV-absorbing contact lenses cannot provide complete protection against the harmful effects of UV on the eyes. But they can supplement the protection provided by anti-UV lenses, in particular by blocking the entry of reflected UV rays into the eye, if the contacts are properly adjusted and of sufficient diameter.
UV protection and polarization are not the same. Polarization can reduce glare. Glare is a reflection from surfaces, such as water or roads. The polarized lens filters light by only allowing certain wave lines, reducing scattering that causes glare. It’s something you might need in addition to UV protection, not a replacement.