ABSTRACT This study was designed to determine if spin‐cast hydrogel contact lenses rotate on the eye, and if so investigate the parameters which influence rotation, if these leuses do rotate, correction of residual astigmatism may be difficult, if not impossible. We monitored the lens rotation associated with 12 specially marked B&L Softens™ contact lenses an six corneas. after insertion and 30 minutes later by use of high speed motion pictures to analyze lens rotation, the film was projected with a stop action projector and the amount of rotation measured with a protractor. Thirty‐one percent of the 144 observations made showed some lens rotation, the majority of which was encyclorotation. Most of the leuses showed, little or no change in rotation between the two time periods. Cornell curvature was the only lens or eye parameter associated with ratation. Why lenses were more likely to rotate on steeper corneas is not fully understood. Our findings indicate that definite way rotate, but there is no definite way of determining in advance of a given lens will rotate on a given, eye. This emphasizes the need for individualized lens fitting and proper patient monitoring.
Harris et al. (Wed,) studied this question.