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Aspheric Lenses 101
can adversely affect its all benefits. Fitting of aspheric lenses is somewhat
similar to the way progressive lenses are fitted.
Pupillary distance: Precise monocular PD measurements position is
essential to point the pole of the lens in front of pupil.
Vertical height: The vertical height of each pupil centre is marked on
the dummy lens of the selected frame.
Rotation: Rotation of the eye must be considered. This requires lowering
the optical centre based on the pantoscopic angle of the frame. The rule is
to lower the optical centre 1 mm for every 2 degrees of pantoscopic tilt.
However, the maximum drop is 5 mm.
SUMMARY
Aspheric lenses have really changed the trend in the ophthalmic lens
designing. The research is still on to make the lens thinner and to improve
the optics. But whatever development occurs, it must be correctly fitted to
really get their advantage.
