The effect of scleral lenses on vision, refraction and aberrations in post‐LASIK ectasia, keratoconus and pellucid marginal degeneration

Abstract

Purpose: To quantify the effect of a single scleral lens design on visual acuity and ocular higher-order aberrations in eyes with post-LASIK ectasia, keratoconus and pellucid marginal degeneration (PMD) that could not achieve satisfactory vision with spectacles or soft contact lenses. Methods: Forty-six eyes of 28 participants fitted with diagnostic scleral lenses (KeraCare) were analysed, including 19, 15 and 12 eyes with post-LASIK ectasia, keratoconus and PMD, respectively. Corrected distance visual acuity (CDVA) and ocular aberrations were measured prior to lens wear and during lens wear after 60 min of settling. An i-Trace aberrometer was used to determine aberrations over a 4.5 mm diameter pupil. Results: Before lens wear, the median (95% confidence interval) values across all groups were: CDVA 0.30 (0.30, 0.40) logMAR, spherical equivalent refraction -2.75 (-5.25, -2.12) D, cylindrical refraction 3.75 (2.50, 5.00) D, higher-orderroot-mean-square error (HO-RMS) 0.90 (0.64, 1.03) lm and vertical coma coefficient C(3,-1) -0.32 (-0.42, -0.12) lm. RMS coma of 0.52 (0.40, 0.74) lm was higher for the keratoconus group than for the other groups (p < 0.05). During lens wear, values improved considerably across all groups: CDVA 0.0 (0.0, 0.00) logMAR, spherical equivalent refraction -0.50 (-0.75, +0.50) D, cylindrical refraction 0.50 (0.00, 0.50) D, HO-RMS 0.32 (0.26, 0.42) lm and C(3,-1) +0.12 (+0.02, +0.19) lm (all p < 0.001 compared to pre-lens wear). While reduced significantly, RMS coma remained higher in the keratoconus group at 0.35 (0.31, 0.52) lm than in the post-LASIK ectasia and PMD groups at 0.17 (0.12, 0.21) lm and 0.07 (0.02, 0.46) lm, respectively (p < 0.05). Conclusions: The KeraCare scleral contact lens reduced ocular aberrations and improved visual acuity in patients with post-LASIK ectasia, keratoconus and PMD. The sign of vertical coma changed in keratoconus and PMD.

Fluid reservoir thickness and aberration relationship in keratoconic eyes with scleral lenses

“…The baseline findings confirm the presence of a significant amount of HOAs in keratoconic eyes, while the use of a SL produced a marked reduction in RMS‐HOAs, coma, spherical aberration, secondary astigmatism and trefoil. This is consistent with several previous reports 6,12,15,34,35 6 .…”

“…Previous studies have reported a substantial increase in coma and spherical aberrations due to the displaced cone 33 . In this study, RMS coma and RMS trefoil were significantly elevated, and this was in agreement with previous studies of keratoconic eyes 6,34 …”

“…Kumar et al 6 . reported a 71%–81% reduction of HOAs with semi‐scleral lenses and 49%–84% reduction with larger diameter SLs 34 in keratoconic eyes. In contrast, Kumar et al 35 .…”

Benefits of Scleral Lens in the Management of Irregular Corneas and Dry Eye Syndrome After Refractive Surgery

“…8,11,12,22,23 However, the reduction in HOAs is less significant in our study, with a 46% reduction compared with more than 60% for other studies. 8,[23][24][25][26] The lower improvement in HOAs could be because of several factors. The age of our patients could have an impact; the average was less than 35 years against 53.8 years for our study.…”

“…The age of our patients could have an impact; the average was less than 35 years against 53.8 years for our study. 8,[23][24][25][26] The type of refractive surgery may also explain the results; in our sample, some patients had refractive surgeries with old methods: PRK or radial keratotomy (20% of eyes), in contrast to the majority of other studies where patients had only LASIK. 8,[23][24][25] In addition, these patients had a lower baseline acuity than in the other studies.…”