Corneal High-Order Aberrations and Backscatter in Fuchs' Endothelial Corneal Dystrophy

Abstract

Purpose Suboptimal visual acuity after endothelial keratoplasty has been attributed to increased anterior corneal high-order aberrations (HOAs). In this study, we determined anterior and posterior corneal HOAs over a range of severity of Fuchs endothelial corneal dystrophy (FECD). Design Cross-sectional study. Participants 108 eyes (62 subjects) with a range of severity of FECD and 71 normal eyes (38 subjects). Methods All corneas were examined by using slit-lamp biomicroscopy to determine the severity of FECD versus normality. FECD corneas were categorized as mild, moderate, or advanced according to the area and confluence of guttae and the presence of clinically visible edema. Normal corneas were devoid of any guttae. Wavefront errors from the anterior and posterior corneal surfaces were derived from Scheimpflug images and expressed as Zernike polynomials through the 6th order over a 6-mm-diameter optical zone. Backscatter from the anterior 120 μm and posterior 60 μm of the cornea were also measured from Scheimpflug images and were standardized to a fixed scatter source. Variables were compared between FECD and control eyes by using generalized estimating equation models to adjust for age and correlation between fellow eyes. Main Outcome Measures HOAs, expressed as root-mean-square of wavefront errors, and backscatter of the anterior and posterior cornea. Results Total anterior corneal HOAs were increased in moderate (0.61 ± 0.27 μm, mean ± standard deviation; p =0.01) and advanced (0.66 ± 0.28 μm; p =0.01) FECD compared to controls (0.47 ± 0.16 μm). Total posterior corneal HOAs were increased in mild (0.22 ± 0.09 μm; p =0.017), moderate (0.22 ± 0.08 μm; p <0.001), and advanced (0.23 ± 0.09 μm; p <0.001) FECD compared to controls (0.16 ± 0.03 μm). Anterior and posterior corneal backscatter were higher for all severities of FECD compared to controls (p ≤0.02, anterior; p ≤0.001, posterior). Conclusions Anterior and posterior corneal HOAs and backscatter are higher than normal even in early stages of FECD. The early onset of HOAs in FECD might contribute to the persistence of HOAs and incomplete visual rehabilitation after endothelial keratoplasty.

Predicting the Prognosis of Fuchs Endothelial Corneal Dystrophy by Using Scheimpflug Tomography

“…All participants underwent Scheimpflug imaging (Pentacam HR; Oculus, Lynnwood, WA) as described previously. 10 Images were acquired at any time during routine clinic hours (7:30AM to 4:30PM), with 75% of all images acquired before 1:00PM. The "4 Maps Refractive" display of enrolled eyes derived from the instrument's software (Pentacam version 1.21r43) was exported as a high-resolution image, as described previously 1 ; only images meeting the instrument's software quality criteria were included.…”

Visual outcome after trifocal IOL implant in a patient with cornea guttata. A case report.

“…4,5 IOL options must be carefully explored when corneal guttae are present. Wacker et al 6 found that anterior corneal HOAs were increased in moderate and advanced Fuchs´ endothelial dystrophy (FED), compared with controls, before clinically visible corneal edema. Likewise, posterior corneal HOAs and corneal backscatter were increased even in mild FED, suggesting that surface aberrations may occur earlier than previously thought.…”

Fuchs' endothelial corneal dystrophy: pathology and treatment outcome

“…; Wacker et al. ; Zhang & Patel ). Furthermore, the level of HOAs typically found in post‐DSAEK patients sufficed to induce a significant reduction in vision in a study by McLaren & Patel ().…”

“…; Wacker et al. ). In the posterior part of the cornea, interface haze between the donor lamella and recipient cornea could affect vision, and graft asymmetry could lead to aberrations from the posterior surface.…”