Pemphigus vulgaris. Pemphigus vulgaris Pemphigus is a rare skin disorder characterized by blistering of your skin and mucous membranes. The most common type is pemphigus vulgaris, which involves painful sores and blisters on your skin and in your mouth.
This is a new technology of tinting the optical lenses, with the tint darker for the upper part of the prescription lens, and the tint gradually becoming lighter for lower part of the lens. This arrangement makes the wearer more at ease by enjoying the better sunshade as well as the better vision acuity seeing through the lower part.
crown lens - a lens made of optical crown glass. concave lens, diverging lens - a lens such that a parallel beam of light passing through it is caused to diverge or spread out. eyepiece, ocular - combination of lenses at the viewing end of optical instruments.