Question about aspherics

**cocoisland58** · 01-13-2007, 07:55 PM

A co-worker with many years experience has stated that Hi-Index 1.67 lenses are not aspheric unless you specifically order aspheric therefore we can save money by specifying non-aspheric Hi-Index 1.67 when we order. Where this strategy suddenly came from I do not know. He also states that poly 1.0 is thinner than a 1.67 and that using these lenses exclusively will save money. I decided to put the question on this forum. Please give my co-worker your expert advice. Thank you. PS...I am all for saving money.

**MarcE** · 01-14-2007, 11:01 AM

When I order stock 1.67 lenses, they are all aspheric. An aspheric lens allows the use of flatter curves. There is no sense in using the expensive 1.67 material if you aren't going to use aspheric designs. Fi you don't use aspheric, then the lens could be thicker than an aspheric poly. The patient would not be happy with that. Also, when I forgot to charge a VSP patient for the aspheric portion of the 1.67 lens, there was not a choice from the lab invoice menu for non-aspheric 1.67.
Regarding the first point - coworker is wrong. 1.60 does come in non-aspheric.

Regarding the second point. It depends. In the range from -4.00 to -6.00, many times the lens will be thinner in poly with a 1.0 CT. go to opticampus.com and do a calculation. When figuring the thickness of poly at 1.0, just subtract 0.5mm from the edge thickness (because the default thickness is 1.5mm)
If you want to save $, the best way is to use stock lenses for SV instead of surfaced lenses. Not only are they less expensive, but they are thinner, except for specifying 1.0mm CT in poly. Most 1.67 lenses are 1.1-1.2mm. Most poly is 1.2mm.
Many times the thinnest lens in the this Rx range is a Resolution Poly. It has an aspheric front and a atoric back with a center thickness at 1.2mm.

Don't use 1.0 poly exclusively - get paid for your expertise.

So your coworker is wrong on both points.

**EyeFitWell** · 01-14-2007, 01:32 PM

My rx is approx. -6, SV. I have worn polycarb in the past and absolutely could not stand it. I know many, many people tolerate poly, but as a consumer, I would expect to be able to purchase high-index if I so choose. Sell exclusively poly, and you'll be just like the "big boys". My opinion from personal experience is that polycarbonate is NOT the ideal lens material.

**cocoisland58** · 01-14-2007, 04:01 PM

I appreciate the information. I figured I already knew the answers but just wanted to make sure before I spoke. I sell poly for weight and safety. CR39 w/src for many jobs, and I prefer Hi-Index for anyone, including myself over 3.00 diopters. The visual clarity is much better and I know this because I have used both for my own glasses. I order stock lenses whenever possible and surface what is necessary. Sure I want to save my employer money but not at the expense of quality and ethics. We have made a name for ourselves with our workmanship, personal care and service. I would hate to see this change.