Contact lens fitting after corneal collagen cross-linking

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.

The aim of this study was to evaluate the changes in CL fitting following CXL.

This is a retrospective study conducted at a tertiary center.

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.

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.

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.

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.