FIX AND FIT

Fixing Fat Lenses

Tricks to help you solve the eyeglass consumer’s #1 complaint…thick lenses

after 40 years in the optical industry, I’d have to say that, though eyewear fashions come and go, the most common complaint people have with their eyewear has remained consistent: that their lenses are too thick. In eyewear, as in clothing, there are a number of tricks that can be used to tone down the appearance of something that is thicker than we’d like it to be.

FRAME SIZE

The first and foremost trick is the frame selection itself. Since minus lenses are thin in the center and thicken toward the edges, they are usually the most problematic. As frame sizes get larger, lenses get thicker; so keeping the overall frame size down will make the most difference regarding keeping lens thickness to a minimum.

DBL

But eyesize is not all there is to the frame size issue. The distance between the lenses (DBL) also plays a significant role in the actual diameter of the edged lens, because a greater DBL will cause the lens to be decentered in order to place the optical center at the patient’s PD.

So making sure that the patient’s eyes are as close to the center of the lens shape as possible, and using the smallest eyesize that the patient’s fashion sense will allow, are the most important factors in controlling thickness.

LENS SELECTION

So now that we’ve got the aspect of frame size in hand, we should also consider what may seem obvious to some, but needs to be mentioned since it makes the second biggest difference in thickness—and that is using high-index lenses.

The greatest obstacle to the patient may be cost, so their motivation to make the lenses thin and beautiful will need to be strong. Also high-index lenses are more reflective, so AR may be in order (more cost). A transparent lens always looks thinner and less obtrusive.

It might also be advisable, particularly in higher prescriptions, to use aspheric or atoric designs in high index. This won’t have much impact on the thickness, but since vision is diminished a small amount with high-index materials, aspheric/atoric designs will help.

POLISHING the edges gives a cleaner and less obtrusive appearance but doesn’t reduce thickness.

ROLLED & POLISHED edges can reduce thickness by about one-third. Use an AR coating to reduce reflections.

FACETS reduce edge thickness by one-third or more and can be a beautiful option with a classy look.

EDGE COATINGS can blend with a frame and make lenses nearly disappear. Add an AR coating and you’ll want to touch them to be sure they are really there.

— Alex Yoho, ABOM