Date of Award
Master of Science in Vision Science
Cristina M. Schnider, O.D., F.A.A.O.
A clinical trial was conducted with twenty subjects to compare patient preference and corneal physiology for hydrogel (soft) contact lenses to that with rigid gas permeable (RGP) contact lenses. Each subject wore each type of lens for six weeks and then switched materials for the remaining six weeks. Initially, half of the subjects wore RGP contact lenses while the other half wore soft contacts lenses. Subjects were monitored after one week, three weeks, and six weeks of wear with each lens type. At the completion of the the study eight of the subjects preferred the RGP contact lenses while twelve of the subjects preferred the soft contact lenses. Excluding foreign body staining, every subject demonstrated corneal fluorescein staining with soft contact lenses equal to or greater than that found with the RGP contact lenses. Although five subjects could not fully adapt to the RGP lenses, seven of the twelve subjects who preferred the soft contacts lenses were also "successful" RGP lens wearers. "Successful" was defined as that the lenses provided clear vision and good comfort without interrupting corneal physiology. The results of this study indicate that 75% of subjects traditionally deemed more suitable for soft lenses could successfully wear RGP lenses, and 40°/o of the subjects may actually prefer them.
Johnson, Tyler J. and Nakagawa, Jason H., "Clinical performance and patient preferences for hydrogel versus rigid gas permeable lenses: A crossover study" (1991). College of Optometry. 942.