You should have two forms of prog identifiers. One will be similar to a magazine and is updated every year or so. It lists pretty much anything that you'll routinely deal with. The other is a walmart only identifier that lists the lenses that we carry and even has the the fitting diagrams as well. Ask your manager about them as they'll make your life a lot easier later.
Hi index lenses are made of a denser material which allows light to travel faster than in Poly which is a more "softer" lens, which is why poly is impact resistant.
The problems with Poly arise when a patient has a high cylinder. Distortion becomes a major issue, as well as chromatic abberations. Some patients report "shadows" with poly more than they do in any other lens.
Hi Index lenses are much more dense, thinner and allow more light to pass through into the eye. It is more favorable for astigmatics as the distortion is minimized.
Always, always, always match the material the patient has been wearing. Tap the lens with a ring, or take it out of the frame and just lightly drop it on the counter in the lab, (careful if it's a glass lens) it will make a hollow sound if it is poly, or a more high pitched plastic sound if it is hi index. CR39 makes a thud.
HOWEVER if distortion is still a problem with a high astigmatic in a hi index, put the patient in CR39 if all else fails. If the patient wears glass, never put the patient in plastic. He/she will hate it! Light travels the fastest in glass.
Hope this helps! :)
http://www.laramyk.com/tools/lad/index.html#
Good link. IF you type "Accolade" or "Accolade Freedom", it'll show you the identifier. Click on the blue magnifier on the left side.
Accolade= Nikon Poly Asph
Accolade Freedom= Nikon 1.67 Customized
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