PILLAR AND COLLAR TECHNIQUE FOR MEASURING THE AXIAL EDGE LIFT OF MULTICURVE RIGID LENSES

Background. The method of using an optical spherometer and a lens thic kness gauge, in combination with a pillar and Collar, bar previously b een shown to be repeatable and accurate (to 0.01 mm) in measuring the edge lilt monocurve lenses. Purpose. This paper goes on to validate th e technique for measurements taken on edge-finished multicurve rigid l enses, Methods, The axial edge lift (AEL) of a series of multicurve ri gid lenses having known values of AEL was measured using an optical sp herometer, a thickness gauge, and contact lens V gauge in a similar wa y as was described in the companion paper, Results, The results show t hat as long as a correction factor of 0.01 mm is applied, as found in the previous paper, the technique will allow satisfactory verification of the edge lift. Conclusions. The technique is accurate and reproduc ible, even in multicurve lens designs, provided that a calibrating cor rection factor of 0.01 mm is applied to account for methodological err or. It will also indirectly allow the accuracy of manufacture of the p eripheral curves and diameters of any rigid contact lens to be verifie d.