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.
This is another monocular depth cue used by painters to suggest that some objects are farther away than others, and it's called the texture gradient. You can see this really clearly in images like a field of grass, where the blades nearest to the viewer are distinct but fade to a wash of green in the distance.