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

Overview

This was a single-site, bilateral, repeated-measures insertion study in habitual soft contact lens wearers. Ten participants were enrolled. All participants attended a Screening/Dispensing Visit at which informed consent was obtained and eligibility was assessed. Eligible participants then wore each of three commercially available daily disposable soft contact lens types - kalifilcon A (Bausch + Lomb), Dailies Total1 (delefilcon A, Alcon) and Precision1 (verofilcon A, Alcon), all -3.00 D - bilaterally for wear times of 0.5, 1, 3, 5 and 10 minutes over a total of 6 study visits. A new lens pair was inserted for each wear time, with a 3-5 minute washout period between lens pairs. Immediately following removal, the right-eye lens was measured for surface refractive index on a Metricon M-2010 Prism Coupler.

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.