All reviews are from people who have redeemed deals with this merchant.
· August 24, 2017
· July 1, 2017
· June 28, 2017
What You'll Get
- $26 for an eye exam and $225 toward prescription eyeglasses and frames ($300 total value)
Corrective Lenses: Shedding Light Where It’s Needed
There’s a lot that can go wrong in the human eye, but fortunately opticians can do a lot to make up for that. Learn how with Groupon’s introduction to corrective lenses.
Light begins its transformation from electromagnetic radiation into visual information by traversing three parts of the eye. It first hits the outermost layer—the cornea—and then enters through the pupil to pass through the lens. The shape and orientation of all three elements are crucial, as they all affect how light is refracted onto the optic-nerve-connected retina at the back of the eye. If these mechanisms don’t get it right, corrective lenses can add a fourth layer to compensate.
For instance, nearsightedness is typically caused by a cornea that is overly rounded from staring at too many billiard balls, or by an eyeball that is too long. As light passes through the pupil, it focuses the light at a point before it hits the retina, creating a blurrier signal. So in this case, concave lenses work to spread the light they intercept before it hits the natural lens.
Today, sophisticated computer programs determine the exact degree of curvature necessary on each surface of the lens to approximate normal vision for eyes with various irregularities. The lenses themselves may be made of several different materials; glass, naturally, is the oldest, although its weight and fragility makes it less popular today. Plastic resin is most widely used, but injection-molded polycarbonate is a favorite of many opticians: along with being durable and light, it also filters out UV radiation and several of the dirtier types of glares.
The Fine Print
Promotional value expires 120 days after purchase. Amount paid never expires. Limit 1 per person, may buy 1 additional as gift. Limit 1 per visit. Valid only for option purchased. Not valid for sale items. Can not be combined with any other offer or promotion. Must use promotional value in 1 visit. Merchant is solely responsible to purchasers for the care and quality of the advertised goods and services.