We evaluated the fitting characteristics of nelfilcon A contact lenses to determine the optimal time for judging lens performance during trial fitting.Methods:
Twenty subjects wore a pair of DAILIES™ (daily disposable soft lenses) for 8 hours. A slit lamp camera was used to videotape lens fit every 5 minutes during the first 30 minutes and at 8 hours. Lens movement and centration were measured in 0.1 mm increments by a single observer.Results:
Lens movement decreased significantly during the first 30 minutes of wearing time (P < 0.001). Mean lens movement measured 0.31 mm initially, decreased to 0.17 mm at 25 minutes of wear, and then increased to 0.33 mm at 8 hours (P < 0.001). At 5 minutes, 93% of eyes showed lens movement within 0.2 mm of the value at 8 hours. Lens centration did not change during the first 30 minutes of wear and was comparable to centration measured at 8 hours.Conclusions:
During trial fitting, the optimal time for evaluating movement of nelfilcon A contact lenses is during the first 5 minutes of wear. Lens movement measured at 8 hours will likely be greater than lens movement measured 10 to 30 minutes after insertion.