Contact lens fitting after corneal collagen cross-linking

الملخص

Background: Contact lenses (CLs) remain the mainstay in improving vision in patients having keratoconus. With corneal collagen cross-linking (CXL) performed worldwide, whether the same CLs can be used or needs replacement needed to be assessed and considered. Aims: The aim of this study was to evaluate the changes in CL fitting following CXL. Settings and design: This is a retrospective study conducted at a tertiary center. Subjects and methods: We analyzed the medical records of patients who underwent CXL and used CL. Data collected included demographics, pre- and post-CXL refraction, corneal topography, anterior-segment examination, and CL [rigid gas permeable(RGP)] fitting details and duration between CXL and RGP fitting. Statistical analysis: Descriptive analysis and paired t-test were used to compare the pre- and post-CXL data on refraction, visual acuity, and CL parameters. The statistical significance was kept at P < 0.05. Results: Thirty-four eyes (keratoconus = 32, pellucid marginal degeneration = 1, and post-LASIK ectasia = 1) of 27 patients who used CL before and after undergoing CXL were analyzed. Mean duration between CXL and RGP lens use was 2.53 months. Mean sphere and cylinder post-CXL was -4.11 ± 4.32 D and -3.54 ± 2.51 D, respectively. A mean change of 0.75 ± 3.72 D sphere and 0.71 ± 3.39 D cylinder was noted post-CXL. The post-CXL best spectacle-corrected visual acuity (CVA) was 0.52 ± 0.36 and with RGP lens it was 0.09 ± 0.18. There was no significant difference in pre- and post-CXL RGP lens CVA (0.07 ± 0.09 and 0.09 ± 0.18, respectively; P = 0.556). Pre-CXL, 3-point-touch fitting was in 24 eyes (70.59%) and central fluorescein pooling was in 10 eyes (29.41%). Post-CXL, 30 eyes (88.24%) had 3-point-touch and central fluorescein pooling was found in four eyes (11.76%). One patient had CL intolerance after CXL. Of the 32 keratoconus eyes, 62.5% (n = 20 eyes) were prescribed new lenses; 37.5% (n = 12 eyes) continued using own lenses. Conclusions: There was no significant difference in refraction, topography indices, and RGP lens parameters pre- and post-CXL. However, changes in RGP lens fitting characteristics suggest a possible change in shape or apex location of the cornea after CXL. RGP lenses remain the best option to improve visual acuity after CXL in corneal ectasia.

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