A study of the Influence of Corneoscleral Profile on Soft Contact Lens Fitting

Purpose: The purpose of this study was to investigate the importance and correlation of the corneoscleral profile (CSP) with contact lens fitting by comparing and analyzing the differences in soft contact lens fitting based on the corneoscleral shape profile identified on slit-lamp images. Methods: Thirty-three subjects (65 eyes) with no history of refractive keratoplasty or eye diseases were fit with multi-curve spherical soft contact lenses after identifying the corneoscleral shape profiles on the superior and inferior ocular surfaces. The subjects were categorized under groups based on the corneoscleral shape profile, and decentration, post-blink movement, lag, and push-up test were examined. The groups were compared based on the test items, and the fitting statuses were checked. Results: On the superior ocular surface, the group with a fluid convex or tangential corneoscleral transition showed significantly larger post-blink movement (p = 0.000) and temporal (p = 0.003), nasal (p = 0.001), and inferior (p = 0.021) lags, and relatively loose fitting (p = 0.041) compared to the group with a marked convex or tangential corneoscleral transition. On the inferior ocular surface, the group with a fluid convex or tangential corneoscleral transition showed significantly larger post-blink movement (p = 0.000) and nasal (p = 0.001) and inferior (p = 0.049) lags, and relatively loose fitting (p = 0.021) compared to the group with a marked convex or tangential corneoscleral transition. Conclusions: Designing the back surface of a soft contact lens based on the corneoscleral shape profile provides a more appropriate fitting condition.