• Eric R Ritchey, Joseph T Barr, and G Lynn Mitchell.
• University of Missouri-Saint Louis, College of Optometry, Saint Louis, MO, USA. eritchey@optometry.osu.edu
• Eye Contact Lens. 2005 Mar 1; 31 (2): 70-5.

PurposeThe Comparison of Overnight Lens Modalities (COLM) Study is a controlled, randomized, clinical pilot study to determine the sample size required to perform a multicenter clinical trial comparing Paragon CRT lenses with CIBA Vision Focus NIGHT and DAY 30-day continuous-wear silicone hydrogel lenses.MethodsTwenty subjects were enrolled in the study. Eighteen subjects, 8 CRT and 10 Focus NIGHT and DAY lens wearers, completed the 3-month study. Visual acuity and refractive quality of life were assessed. Nonparametric statistics were used to analyze differences within and between treatment groups for refraction, visual acuity, and refractive quality of life. The Wilcoxon rank sum test was used to analyze differences between the groups in refraction, visual acuity, and refractive quality of life. The Wilcoxon signed rank test was also used to monitor changes in refraction, refractive quality of life, and visual acuity within a group. Sample size calculations were performed to determine the sample size needed for a large-scale clinical trial.ResultsNo statistically significant difference was observed between the groups for 12 of 13 scales on the National Eye Institute Refractive Error Quality of Life Instrument (NEI RQL-42) after treatment. A statistically significant difference was observed between the CRT and Focus NIGHT and DAY groups after 3 months for the NEI RQL-42 dependence-on-correction scale (P=0.0032). There was a significant change within the CRT group between baseline and 3 months (P=0.0156). No statistically significant difference was observed between the two groups in Bailey-Lovie high- and low-contrast visual acuity after 3 months.ConclusionsThe NEI RQL-42 may be able to detect differences in refractive quality of life between two contact lens treatment groups for the dependence-on-correction scale. Paragon CRT and CIBA Vision Focus NIGHT and DAY lenses produced similar high- and low-contrast visual acuity in this study. A sample size of 126 subjects per group is required to find a 10-unit difference on the NEI RQL-42.

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