Scleral asymmetry as a potential predictor for scleral lens compression

• Published in: Ophthalmic & physiological optics Vol. 38; no. 6; pp. 609 - 616
• Main Authors: Consejo, Alejandra, Behaegel, Joséphine, Van Hoey, Maarten, Iskander, D Robert, Rozema, Jos J
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.11.2018
• Subjects: anterior eye surface; Asymmetry; Compression; Contact lenses; corneo‐scleral topography; impingement; lens compression; miniscleral contact lens; corneo-scleral topography; anterior eye surface; miniscleral contact lens; impingement; lens compression
• ISSN: 0275-5408; 1475-1313
• DOI: 10.1111/opo.12587

Purpose To identify the position and magnitude of lens compression due to short‐term miniscleral contact lens wear, as well as evaluating the usefulness of scleral asymmetry as a predictor for scleral lens decentered compression. Methods Fourteen healthy subjects (mean ± S.D.: 29.2 ± 6.0 years) wore a highly gas‐permeable spherical haptic miniscleral contact lens during a 5‐h period. Corneo‐scleral height Fourier profilometry was captured using an Eye Surface Profiler (www.eaglet-eye.com) before and immediately after lens removal. Scleral asymmetry, lens compression location and magnitude were processed using custom‐made algorithms, both globally and for scleral quadrants. Results Miniscleral contact lenses do not set uniformly on the ocular surface, with the largest decentration seen along the horizontal meridian. The greatest flexural stress exerted by the lens on the ocular surface occurs at the point coinciding with the inner diameter landing point of the lens and not with its overall diameter. Scleral asymmetry was significantly correlated with compression location (R = 0.71, p = 0.002) and compression magnitude (R = 0.81, p < 0.001), showing its potential as compression predictor. Conclusion Larger amounts of scleral asymmetry will lead to more decentration of spherical haptic scleral lenses. Objective and accurate methods, like the one presented here, could help the practitioner prevent cases of scleral blanching or discomfort due to an excessive compression by the lens.