Ralph Stone


PURPOSE. Although rigid gas permeable (RGP) lenses continue to be the lens type of choice for many contact lens wearers, lens care product development for this modality has been relatively stagnant and lagged behind that of soft contact lens care products. New formulation technology including an HP-guar/borate polymer system has been used to develop a novel RGP multi-purpose solution (Unique-pH). Laboratory and clinical studies were conducted to evaluate the performance characteristics of the product. METHOD. Laboratory studies evaluated several product attributes including the pH/viscosity profile, desorption (resistance to removal), adsorption (wettability), cleaning ability and microbiological efficacy. A 90-day clinical study at six sites evaluated the safety and efficacy of the multi-purpose solution compared to another marketed RGP multi-purpose solution in 115 subjects.

RESULTS. The pH/viscosity relationship indicates that the solution is less viscous at the lower pH (approx. 7.0) in the bottle for ease of handling during cleaning and conditioning. The polymer system structurally transforms when exposed to the slightly higher pH of the tear film allowing the solution to become more viscous and to coat and cushion the lens and eye. Adsorption and desorption profiles indicated better lens wettability and increased resistance to removal from lenses compared to other available RGP solutions. Laboratory deposited lenses cleaned with the solution were comparable to undeposited lenses. The new RGP multi-purpose solution, preserved with POLYQUAD, provided for a minimum reduction of fives logs for both bacteria and fungi, indicating excellent antimicrobial efficacy. Finally, the 90-day clinical study demonstrated the safety and efficacy of the product in RGP lens wearers with perceived viscosity being one of the most preferred attributes.

CONCLUSIONS. Results indicate that the new technology provides a solution that compares favorably to currently marketed RGP multi-purpose solutions and is a convenient alternative to other available RGP lens care regimens.


Year: 2001

Program Number: Poster 141

Author Affiliation: Alcon Research, Ltd.

Co-Authors: Jerry Stein, Leslie Napier, masood chowhan, bahram Asgharian

Co-Author Affiliation: n/a

Room: Exhibit Hall C