The aperture is the opening formed by the blades of the iris or diaphragm in the lens, through which light passes to expose the film. Aperture size is usually given in f-numbers, ...
Corrective lenses that have two powers of correction. Typically the majority of the lens is corrected for distance vision while a small are is corrected for near vision. Bifocals ...
Medical prescription terms were originally all written in Latin. Many of the Latin terms continue to be used today. Eyeglass prescriptions are somewhat different, and you can ...
A tiny amount of a fluorescein dye is placed in the tear film. The color will make microscopic dots appear where the eye has become dry. Excessive staining is an indication of dry ...
A prism is a lens that will bends light towards its base. Prisms are used to measure the angle of deviation in strabismus to correcting binocular polyopia when the eyes become ...
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