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Steve wrote:
Hello, I have a question about prescription sunglasses that many optometrists have been unable to clearly answer. I am hoping for your insight on the matter. I have fairly high astigmatism of -5.25 on both eyes and sphere of +3.25. Would that sort of prescription be suited for aviator type sunglasses? Also, can mirror coatings be applied to prescription sunglasses? I appreciate your time and response. Steve
Dr Joan Hansen's response:
Steve, Your lenses are thicker in one part of the lens than another. This cause the edges to become very thick in the deep aviator frame shape, and they may not stay in the frame well. Your prescription would be best in a smaller frame with rounded corners. In my experience, mirror coatings are only applied to glass lenses, and these are not used very much any more as they are not as safe an option to wear.
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Nancy wrote:
I wear progressive lenses and I purchased a pair of sunglasses. They are the type that change when you are out in the sun and work great. The only trouble is that they do not change when I am driving my car as all current cars have tinted windows. Is there a type of lense that I can buy that would be progressive so I can see the road and the dials and also be sunglasses? Thanks in advance for your advice.
Dr Henry Smit's response:
Dear Nancy:
There are lenses available that darken moderately when worn inside a vehicle, but these lenses do not become completely clear indoors. Transitions XTRactive lenses, for instance, turn very dark when worn outdoors, have a moderate tint when worn inside a vehicle, but remain somewhat tinted when worn indoors or in low light conditions. This residual tint may make night driving more difficult for persons who have early stage cataracts, or other conditions that affect the normal transmission of light into the eye. For driving in bright conditions, and for most other outdoor activities, your best option appears to be having a separate pair of progressive prescription sunglasses with a permanent tint. These will allow you to have fully tinted lenses inside and outside of the vehicle, and the progressive prescription will allow you to see the road ahead as well as your dashboard instruments. However, these lenses would be unsuitable for night time driving and indoor activities – you would need to wear a non-tinted prescription for these activities.
Hope this is helpful.
Dr. Smit
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Re: Polarization and UV Rays
Diane wrote:
Do polarized sunglasses block UVA and UVB rays? Thank you
Dr Joan Hansen's response:
Polarization by itself does not block UV rays; however it blocks glare. The UV protection must be added to the lenses just as it is in all other sunglasses. In other words both UV protection and Polarization need to be specified individually. Dr. Joan Hansen – Optometrist for CAO
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