The why and wherefore of soft lens visual performance

Although significant advances have been made over the past decades in improving the physiological performance of hydrogel lenses, little has been done to understand and improve the quality of vision experienced by soft lens wearers. Yet, almost since their inception, the literature has revealed numerous reports claiming that soft lenses provide inferior visual performance compared to spectacles or rigid contact lenses. This paper outlines those physical, physiological and optical factors which may be responsible for less than optimum soft lens vision, and describes the results of a series of investigations designed to pinpoint the most probable culprit in soft lens designs typically used by today's clinician. The results of these studies will provide the clinician with a better understanding of the contact lens/ocular environment interactions which affect soft lens visual performance and a guide to solving their soft lens patients day-to-day vision problems.