Clinical results comparing high-oxygen and low-oxygen permeable soft contact lenses in France

This article reports clinical results comparing a high-oxygen permeable (HDk) silicone hydrogel soft contact lens with a low-oxygen permeable (LDk) soft hydroxyethyl methacrylate contact lens when worn on an extended-wear basis.

Six practitioners in France enrolled 134 subjects in this 4-month, open-label, multicenter, prospective, randomized, cross-over study. Subjects were randomized to receive either an HDk lotrafilcon A or an LDk etafilcon A soft contact lens. Subjects crossed over to the alternative lens after either 3 months' experience with the HDk lens or 1 month's experience with the LDk lens. Clinical and subjective data were collected at scheduled follow-upvisits.

The subjective data has been reported in a separate article. Both types of lenses gave similar performance for visual acuity. Biomicroscopic examination findings averaged below grade 1 (trace) for both lenses throughout the study. A statistically significant difference for limbal redness was found at 1 week (HDk = 0.11; LDk = 0.33; paired-t test, P < 0.05). Eight of 10 biomicroscopic signs improved within 1 week when subjects changed from the LDk lens to the HDk lens. Deposits for both lenses remained below grade 1, and wetting was nearly perfect for both lenses throughout the study. Over 90% of fittings for both lenses were acceptable or optimal.

The improvements in biomicroscopy signs seen with the HDk lens may provide practitioners an alternative to LDk contact lenses for extended wear.