Abstract
Purpose:
To evaluate how closely contemporary contact lens performance approaches the ideal of no lens wear in terms of ocular adverse events (AEs) and subjective responses.
Methods:
Retrospective analysis of data (n=1945) from 45 clinical trials, each with a different wearing modality (39 contact lens/solution daily wear [DW] combinations, 6 daily disposable [DD] contact lenses and one group of emmetropic (non-contact lens wearers) was conducted. All trials lasted for 3 months and were carried out under the same protocol where approximately 40 participants wore their assigned contact lens on a daily wear basis. 14 different lens types and 8 solution types were included in the study. Physiological and subjective responses were collected at regular intervals. Data were converted into a ratio between 0 and 1 to represent the relative performance within the series, with a higher ratio indicating better performance. Confidence limits of the AE rates and end of day comfort (EODC) scores from emmetropes, were used to establish the boundary criteria for acceptable no-lens wear performance.
Results:
No-lens performance equivalence boundaries were defined at a minimum ratio of 0.77 for both AE and EODC. One DW combination and 1 DD contact lens met the standard for both AE and EODC. The results for ninety six percent of the modalities studied performed below the non-lens wear equivalence criteria for any AE and EODC. Despite, daily disposables performing well for AE (ratio range: 0.80 to 1.00), their EODCs were not consistently high (ratio range: 0.10 to 0.79). Insertion comfort ratios correlated positively with both EODC (r=0.7, p<0.001) and Solution Induced Corneal Staining ratios (r=0.42, p<0.01).
Conclusions:
The performance of only a small proportion of current contact lens systems approximates that of no-lens wear, in terms of AEs and EODC. Favourable AE performance is not necessarily accompanied by high comfort ratings.