Sun­glasses must of­fer good UV pro­tec­tion

Daily Freeman (Kingston, NY) - - YOUR DAILY BREAK - Anthony Ko­maroff Ask Dr. K

Dur­ing my last eye exam, my eye doc­tor ad­vised me to buy a pair of “high qual­ity” sun­glasses. But she didn’t tell me what she meant by high qual­ity. Can you help?

When you buy sun­glasses, it’s nat­u­ral to look for a style that looks good on you and is com­fort­able. But don’t fail to con­sider the most im­por­tant de­tail: the amount of harm­ful ul­tra­vi­o­let (UV) ra­di­a­tion the lenses screen out. With­out proper UV pro­tec­tion, sun­glasses can work against you by en­abling you to see com­fort­ably in light that is harm­ing your eyes.

UV ra­di­a­tion can pen­e­trate the clouds, even on over­cast win­ter days. That’s why the Amer­i­can Academy of Oph­thal­mol­ogy rec­om­mends that ev­ery­one wear sun­glasses when­ever they are out­doors.

Since 1998, the FDA has reg­u­lated non­pre­scrip­tion sun­glasses as med­i­cal de­vices. It re­quires lenses to be im­pact-re­sis­tant, non­toxic and non­flammable. Be­yond that, though, op­tions vary, and some choices are bet­ter than oth­ers. You’ll want to con­sider the fol­low­ing:

• THE LA­BEL. Look for 99 per­cent or 100 per­cent UV pro­tec­tion, or UV400, which means the lenses ab­sorb wave­lengths up to 400 nanome­ters, thus block­ing all harm­ful UV rays.

• THE SIZE. The larger the lenses, the bet­ter pro­tec­tion they of­fer. Wrap­around lenses are the best be­cause they pre­vent UV rays from en­ter­ing at the side.

• THE SHADE. Although it may seem coun­ter­in­tu­itive, darker isn’t au­to­mat­i­cally bet­ter. The dark­ness of the lens af­fects only the abil­ity to fil­ter out vis­i­ble light. The pro­tec­tion from UV light is con­ferred by coat­ings ap­plied to the lens.

Yet shad­ing is im­por­tant in pro­tect­ing you from glare — a dif­fer­ent prob­lem from UV light. For many peo­ple, very bright light causes an un­pleas­ant sen­sa­tion. It makes you squint, and it’s harder to see clearly. Lenses come in dif­fer­ent shades, for dif­fer­ent sit­u­a­tions. For ex­am­ple, dark lenses are best for a sunny day on the water, while lighter tints may be bet­ter choices for over­cast days. These days, you can get “pho­tochromic” lenses that change their shade de­pend­ing on the amount of light. In­doors, they are clear. Out­side in bright sun, they be­come a dark shade.

• OP­TI­CAL QUAL­ITY. When you’re try­ing on sun­glasses, fo­cus on a ver­ti­cal edge or line and move your head back and forth. If the line wig­gles, the lens may have an op­ti­cal de­fect.

• THE FIT. You want the frames to fit com­fort­ably, with the lenses di­rectly in front of your eyes.

• THE COST. There is no re­la­tion­ship be­tween the price tag on a pair of sun­glasses and the pro­tec­tion it of­fers. As long as the la­bels spec­ify 99 per­cent or 100 per­cent UV pro­tec­tion, or UV400, and have no op­ti­cal de­fects, an in­ex­pen­sive pair from a dol­lar store will do the job as well as pricier sun­glasses from a de­signer bou­tique. If you want glasses that change their shade de­pend­ing on the amount of light, such pre­scrip­tion lenses will cost you more.

Most peo­ple who buy ex­pen­sive sun­glasses are spend­ing their money on how they think the glasses look, not on the “high qual­ity” of the glasses.

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