Talk:Corrective lens

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[edit] Comments

Some of the explanations need better wording and more accurate descriptions. Maybe someone more knowledgable can help in this regard.MichaelGoldshteyn 14:48, 8 September 2006 (UTC)

Most people do not seem to be bothered by a slight or even moderate amount of chromatic aberrations. However, the choice of material and index are the only criteria that are available to the average consumer. Best base curve selection and even selection of aspherics and atorics for all material types are usually not provided as options to opticians, let alone consumers. Such decisions lie solely with the lab producing finished and semi-finished blanks.MichaelGoldshteyn 14:48, 8 September 2006 (UTC)

Removed this text added by 155.136.80.163: "Polycarbonates are typically manufactured from sheeps' bladders, which contain a specific diamino - benzoic acid molecule, relatively low in molecular weight, but relatively unwearing." which appeared under High-index materials (Polyurethanes) heading, since:

  • It has nothing to do with polyurethanes, as stated
  • If true for polycarbonates, which I doubt, since they are synthetic plastics, it should be added to the page on polycarbonates not corrective lenses.

MichaelGoldshteyn 15:27, 12 September 2006 (UTC)

Undid the change made by 71.136.6.98, who changed the Fraunhofer line type from the correct He to the incorrect Na. Clearly, said user did not go to the Abbe Number link and read about which Fraunhofer line is used for Abbe number references in the US (i.e.,He-D3 or more commonly the d-line, with respective Abbe number Vd ) and Europe/Japan (i.e., Mercury e-line with respective Abbe number Ve ).
References, in order of authority:

MichaelGoldshteyn 16:31, 3 October 2006 (UTC)

Q: Polycarb lenses are supposed to be more scratch resistant than most lenses according to other sites. The article states that polycarb lenses scratch more easily than most lenses. Can someone check this?

A: Polycarbonate in and of itself is not very scratch resistant. It is the hard scratch resistant coating that is almost always applied to the polycarbonate that gives it the scratch resistance often found in lenses made from the material. The reason that uncoated polycarbonate scratches easily is that it is a very soft material. This softness is what gives it much better impact resistance, since it bends rather than breaks. However, it is this same softness that makes polycarbonate easy to scratch by harder materials. See polycarbonate and also http://www.engineeringtalk.com/news/gad/gad192.html for more information. MichaelGoldshteyn 20:15, 19 December 2006 (UTC)

Aspheric lenses are not only for cosmetics, they provide better "picture". At least stright lines looks stright.

Curtis Williams, please correct your assertion that: This qualification is necessary since best-form spherics are always better than aspherics for an ophthalmic lens application. This assertion is incorrect! MichaelGoldshteyn 17:14, 25 January 2007 (UTC)

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