Impact of Manual Contact Lens Modification on Visual Performance and Wearing Comfort

Purpose. To evaluate the effects of manual post-processing of rigid gas-permeable (RGP) corneal contact lenses on subjective and objective outcomes and to determine the proportion of new lens fittings requiring manual modification.

Material and Methods. This prospective, interventional before-and-after observational study without a control group assessed subjective outcomes using two standardized questionnaires. Newly fitted contact lenses (n = 40) and established RGP lenses (n = 38) were evaluated before and after manual posterior surface modification or surface polishing, respectively, and again after at least one week of wear. High-contrast visual acuity, glare visual acuity, and contrast sensitivity were measured before and after polishing. Additionally, 101 consecutive new RGP lens fittings from the previous year were retrospectively analysed to determine the frequency of manual post-processing.

Results. Statistical analyses demonstrated significant differences in median wearer comfort before and after manual posterior surface modification in newly fitted RGP lenses, increasing from 7/10 to 9/10 (p = 1.71 × 10−7). In established wearers, significant differences were also observed for median wearer comfort (8/10 to 10/10; p = 4.51 × 10−5) and subjective visual performance (8/10 to 10/10; p = 3.08 × 10−16). Furthermore, statistically significant differences were found for high-contrast visual acuity, glare visual acuity, and contrast sensitivity (all p < 0.05), indicating favourable changes within the study population. Manual post-processing was performed in 61.4 % (62/101) of new lens fittings.

Conclusion. In this cohort, manual post-processing was associated with improvements in subjective outcomes and selected objective measures.