Retrospective Analysis of Vision Correction and Lens Tolerance in Keratoconus Patients Prescribed a Contact Lens With Dual Aspherical Curves

Clinical evaluation of flat peripheral curve design with aspherical-curve and multi-curve hard contact lenses for keratoconus

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.

Current perspectives in the management of keratoconus with contact lenses

Our aim is to review current and significant articles on contact lens wear in keratoconus patients. A comprehensive literature search of PubMed was performed for the following topics on contact lens wear in keratoconus patients: (1) characteristics of contact lens wearers, (2) safety and efficacy, (3) complications, (4) fitting techniques, (5) contact lens wear after procedures/surgeries, (6) patient satisfaction. A total of 104 studies were finally selected and reviewed. Gas permeable (GP) lens wear provided significantly better vision than glasses. Special cone design lenses had better patient comfort levels though there was no difference in best corrected visual acuity among the GP lenses. Soft lenses showed good efficacy for the treatment of mild-to-moderate keratoconus with newer designs improving visual performance such as customised hydrogel and novel pinhole lenses. Scleral and hybrid lenses provide good visual acuity and comfort for keratoconic patients previously intolerant to RGP lenses. RGP lens wear post-cross linking (CXL) is relatively well-tolerated. Contact lenses may still be required post intrastromal corneal ring procedures and post keratoplasty. Scheimpflug imaging and anterior segment optical coherent tomography (ASOCT) are useful in contact lens fitting. Computerized contact lens fitting techniques could reduce the chair time of lens fitting as well as improve comfort and visual performance. Contact lenses play an important role in the visual rehabilitation of keratoconus patients. New contact lens designs and materials have significantly expanded the available fitting options for keratoconus patients. Imaging technology can be utilized to guide contact lens fitting.