Purpose: To determine whether mucin ball (MB) formation is protective against corneal infiltrative events (CIEs) as previously reported.
Methods: Two hundred eighty-two eligible participants were enrolled at three sites in the USA. Participants began a 1-month continuous wear run-in period with high modulus lotrafilcon A lenses to assess their ability to form MBs (phase 1). Subsequently, they were stratified by this characteristic and randomized to balafilcon A or comfilcon A lenses for 7-day extended wear and followed for 1 year (phase 2). MB formation in each phase was defined as repeated presence of any MBs on a person level. Multivariable Cox proportional hazards regression was used to model the probability of a CIE as a function of MB formation in each phase and other covariates.
Results: Of the 282 participants who entered phase 1, 218 of them entered the phase 2 randomized trial during which 33 CIEs occurred. Overall, 74%, 61%, and 79% of participants repeatedly produced MBs in lotrafilcon A, balafilcon A, and comfilcon A lenses, respectively. Early repeated MB presence in phase 1 with lotrafilcon A lenses significantly increased the rate of CIEs in phase 2 (12-month follow-up) by 466% (HR 4.66, 95% confidence interval 1.10–19.79, P = .0372). Repeated, longer-term MB presence during wear of balafilcon A or comfilcon A in phase 2 did not significantly reduce the incidence of CIEs; however, it significantly decreased the rate of CIEs by 62% (hazard ratio (HR) 0.380, 95% confidence interval 0.145–0.998, P = .0494).
Conclusions: The overarching hypothesis that MB formation is protective against CIEs throughout extended wear was not supported. Although a protective effect of longer-term MB presence on rate of CIEs was detected, early-onset MB formation substantially increased the hazard for CIE in subsequent wear with different lens types.
*OD, PhD, FAAO
University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, Ohio (LS-F); Departments of Ophthalmology & Visual Sciences (LS-F) and Epidemiology & Biostatistics (SD, YJ), Case Western Reserve University, Cleveland, Ohio; Western Reserve Vision Care, Beachwood, Ohio (MJS); The Ohio State University College of Optometry, Columbus, Ohio (DOM, JJW); and Johnson & Johnson Vision Care, Inc., Jacksonville, Florida (TW).
Loretta B. Szczotka-Flynn, University Hospitals Eye Institute, 11100 Euclid Ave., Lakeside 4126C, Cleveland, OH 44106, e-mail: firstname.lastname@example.org