Future Optometrists

ABERRATIONS ASSOCIATED WITH SPECTACLE LENSES LENS ABERRATIONS     One of the first decisions to be made while dispensing a new prescription is the choice of lens form. When the eye views along optical axis of spectacle lens, the form of lens does not matter and image formed by lens is not afflicted with any defects or aberrations which might affect its sharpness or its shape.                   But in actual world, the eyes turn behind the lens to view through off-axis visual points and it is then the form assumes importance. Ideally, the off-axis performance of lens should be same as its performance at the optical centre. But it is never so.      The off-axis images are afflicted with various types of aberrations, which spoil the quality of image formed by the lens.     There are 6 major lens aberrations that work against obtaining a perfect image through the periphery of the le...