Abstract
Aspherical- and multi-curve rigid gas-permeable hard contact lenses (HCLs) have a flattened curve in the peripheral zone and are mostly used for patients with keratoconus who cannot wear glasses, soft contact lenses, or spherical HCLs. In this retrospective study, a total of 95 eyes of 77 patients who used aspherical- or multi-curve HCLs (mean age: 40.0 ± 11.0 years) were evaluated. This study examined the types of aspherical- and multi-curve HCLs, best-corrected visual acuity (BCVA) values before and after wearing HCLs, the association with the Amsler-Krumeich classification, duration of wear, corneal/conjunctival disorder, and the frequency of changing HCLs. There were 78 eyes that used aspherical-curve HCLs and 17 that used multi-curve HCLs. BCVA significantly improved from 0.42 logMAR to 0.06 logMAR after wearing either form of HCL. The Amsler-Krumeich classification showed that aspherical-curve HCLs were commonly used for patients with stage 2 keratoconus, and multi-curve HCLs were commonly used for stage 4 patients. The BCVA values were worse when the disease stage was more severe (stages 3 and 4) regardless of HCL type. The mean base curve of the lenses was steeper in multi-curve HCLs than in aspherical-curve HCLs. The more severe the disease stage, the steeper the base curve in both aspherical- and multi-curve HCLs. The duration of wear significantly improved from 2.1 h to 10.2 h, and corneal/conjunctival disorder similarly improved. The mean frequency of changing HCL types was 1.1 times. This study suggests that a flat peripheral curve design with aspherical- and multi-curve HCLs is useful for patients with keratoconus.
Highlights
Keratoconus is a bilateral corneal dysmorphic disorder in which the center of the corneal stroma is thinned and protrudes anteriorly
The best-corrected visual acuity (BCVA) significantly improved from 0.42 ± 0.45 to 0.06 ± 0.16 logarithm of the minimum angle of resolution (logMAR) in the whole study population (p < 0.001; Wilcoxon signed-rank test)
The BCVA in the aspherical-curve hard contact lenses (HCLs) group improved from 0.37 ± 0.42 to 0.06 ± 0.13 logMAR, and those in the multi-curve HCL group improved from 0.66 ± 0.55 to 0.05 ± 0.06 logMAR
Summary
Keratoconus is a bilateral corneal dysmorphic disorder in which the center of the corneal stroma is thinned and protrudes anteriorly.
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