Surface Refractive Index Shift of Kalifilcon A Compared With Dailies Total1 and Precision1 Lenses

Rationale: earlier work (ROC2-20-012) showed a change in surface refractive index for Dailies Total1 (delefilcon A) and Precision1 (verofilcon A) lenses after 5 minutes of wear, attributed to a change in surface water content. ROC2-21-007 was designed to determine whether that change occurs in less than 5 minutes. Three study lenses (one test, two controls) were each worn bilaterally. Wear times of 0.5, 1 and 3 minutes were completed at one visit and 5 and 10 minutes at another visit for each lens type, giving 6 visits of approximately 30 minutes each, each on a separate day; the clinical investigation took approximately 2 weeks. Lens type order followed the study randomization schedule prepared before enrolment by an unmasked statistician not otherwise involved in the study; unmasked study personnel dispensed and collected study materials so that the participant and Investigator remained masked. Endpoint: surface refractive index of the worn right-eye lens, measured on a Metricon M-2010 Prism Coupler, compared with unworn (baseline) values for the same lens types. Continuous data were summarized with n, mean, standard deviation, median, minimum and maximum, and paired t-tests were used to compare unworn with worn values, with p < 0.05 considered statistically significant.