(content from https://www.allaboutvision.com/sunglasses/rx.htm)
Are prescription sunglasses a good idea?
You may sometimes find yourself driving down the road, sun shining in your eyes, as you search in vain for those clip-on or magnetically attached sun lenses that came with your prescription eyeglasses.
At times like these, you might find that prescription sunglasses are much more convenient and more than worth the additional investment.
Contact lens wearers, too, may find that wearing prescription sunglasses is sometimes a far more practical alternative outdoors. For example, you may not want to wear your contact lenses on the beach where your eyes can become itchy and watery as you battle the effects of sand, sun, wind and water.
Even the non-prescription sunglasses you wear over your contact lenses may not provide enough protection. Also, wearing your contact lenses while swimming is a bad idea because of the possibility of potentially serious eye infections caused by microorganisms in the water.
But with prescription sunglasses, you have the option of wearing them anytime outdoors without the need to search for clip-on sunglasses or deal with contact lenses.
More Advantages Of Prescription Sunglasses
If you have a vision problem that requires corrective prescription eyewear, you have several choices when it comes to sunglasses. Prescription sunglasses are available for virtually any lens prescription, including bifocal and progressive lens options if you are presbyopic and need lenses to help you read that magazine or book at the pool.
These types of sunglasses also can help you if you need reading glasses only or if you wear contact lenses to correct only your distance vision and still need that additional boost for reading.
You might also consider prescription swimming goggles when it comes time to take a dip.
Prescription Sunglasses Come In Many Frame Styles
The styling of prescription sunglass frames is nearly the same as with non-prescription sunglasses. Almost all of the same fashion, designer and celebrity eyewear options apply.
Availability is limited when it comes to certain wraparound sunglasses that curve around the head. Prescription sunglasses made with extreme curves typically distort vision.
However, several manufacturers offer wraparound prescription sunglasses with less extreme curves. Typically these are available in a limited prescription range, so you would need to discuss options with an optician.
Unlimited Lens Options
Prescription sunglasses are available in all lens materials, including high-index, polycarbonate, regular (CR-39) plastic, Trivex (a lightweight material similar to polycarbonate) and glass.
Though glass lenses arguably provide the best optical quality, they are no longer the most popular choice for sunglasses. This is because they are much heavier than lenses made of other materials, and they can shatter easily. However, they are still available if you request them.
Another sunwear option is to purchase prescription eyeglass lenses that have a photochromic tint. These lenses are often called "transition lenses" because the leading manufacturer of plastic photochromic lenses is a company called Transitions Optical. Photochromic lenses automatically darken in sunlight and then return to a relatively clear state indoors.
Photochromic lenses are very convenient, but they do have a drawback: UV rays are required to activate the tint. Because most car windshields block a significant amount of UV, photochromic lenses usually don't darken very well inside a car.
For the ultimate prescription eyewear suitable for all lighting conditions, some opticians recommend eyeglasses with photochromic lenses and a frame with integrated magnetic clip-on sunglasses.
The photochromic lenses provide automatic sun-sensitive light adjustments for greater comfort outdoors. And the clip-on sunglasses can be conveniently stored in your vehicle for those bright, sunny days when you need a darker driving lens.
UV And Glare Protection
As with non-prescription sunglasses, your primary concern when buying prescription sunglasses is that the lenses block 100 percent of the sun's harmful UV rays.
UV protection is unrelated to the color and density of the tint in sunglass lenses, so you can choose any lens color and darkness you like, as long as your optician verifies that the lenses provide 100 percent UV protection.
For added glare protection from light bouncing back from reflective surfaces (like water, snow, sand and concrete pavement), prescription polarized sunglasses also are available.
Cost Of Prescription Sunglasses: Maybe Cheaper Than You Think!
Many optical shops offer special discounts on prescription sunglasses if you purchase them at the same time you buy your regular eyeglasses. Ask your optician for details.
If you are budget-minded, try listing all the features you want in prescription sunglasses and then compare pricing of favorite brands that have just what you need. You could find a bargain.
Gary Heiting, OD also contributed to this article.