Lens thickness

[Ironhorse]

Hi Everyone. I have been on this site for a few years and just registered. I wanted to ask a question about how to determine finished thickness on rx lenses. I know it depends on index, material, frame measurements, pd and rx etc. Is there a formula that I can use? Thanks in advance. Also, the reason i am asking is that when a patient asks how thick will my lenses be I want to be able to tell them to suggest the right product for their needs.

[optical24/7]

http://www.opticampus.com/tools/thickness.php

Darryl has a great site. Use the calculator above. Welcome to OB!

[finefocus]

For eyesize, use an ED. A 50mm square is bigger than a 50mm circle.

[PRECISIONLAB]

When I was trained on a 108 manual gen..yes in the 80's..rule of thumb was 1.0 mm per diopter @ 50mm. So for example a +1.00 would measure 2.2 edge with a 3.2 center..+2.00 with a 4.2 and so on. To varify prism a +1.00 lens with one diopter of prism I would caliper 2.2 apex with 3.2 at the base. All this was based on 1.53 (Glass) to 1.498 (CR 39). Index, minimums for material type, MBS and decentration all factor in but for a ball park estimation for the patient this should work.

[Ironhorse]

Thanks for the quick feedback. I appreciate the help and have already put your ideas to good use. The opticampus tool website is a great reference.