That was the subject and focus of a study of silicone contacts and contact lens solutions. Alcon, the maker of Optifree, made the study widely known in the industry and used it to sell their solutions. Their solutions did not cause any significant amount of SPK. Of course, a lawsuit by Bausch and Lomb followed. The superficial punctate keratitis does resolve and does not cause any permament damage. Heavy amounts of SPK may be associated with discomfort, so changing solutions is indicated. The effects and significance of long term SPK is not known at this time.