Evaluation of corneal staining with an antihistamine-releasing contact lens

Practitioners can be reassured that this antihistamine-releasing contact lens has no additional effect on corneal epithelial integrity.

To evaluate the effect of an antihistamine-releasing soft contact lens on corneal epithelium integrity when worn on a daily disposable modality for 12 weeks.

Two clinical trials using the same randomised, double-masked, placebo-controlled, parallel-group design enrolled healthy contact lens wearers. Participants wore either etafilcon A with 0.019 mg ketotifen (test; n = 374) or etafilcon A with no added drug (placebo; n = 186). Assessments were conducted at baseline, 1 week and 4, 8, and 12 weeks. Slit-lamp evaluations of corneal staining (using sodium fluorescein) in all regions of the corneas of both eyes were graded on a 0-4 scale. Data from all randomised participants were analysed.

Corneal staining was infrequent and, where present, was mild (Grade 2) or trace (Grade 1). There were no Grade 3 or 4 findings of corneal staining. The overall proportion of findings of Grade 0 corneal staining was 95.86% with the test lens and 95.88% with the placebo lens. The odds of no staining were not statistically different between the test and placebo lenses (Odds Ratio: 0.96, 95% Confidence Intervals: 0.76 to 1.20). There were no serious ocular adverse events or signs of ocular surface medicamentosa.

Both test and placebo lenses were well tolerated by subjects during the 3 months of wear. The antihistamine-releasing contact lens does not significantly impact corneal epithelial integrity.