Avoiding Hyperopic Surprises After Descemet Membrane Endothelial Keratoplasty in Fuchs Dystrophy Eyes by Assessing Corneal Shape.

Abstract

It is unclear which patients unexpectedly have a hyperopic refractive outcome after combined Descemet membrane endothelial keratoplasty and cataract surgery (triple DMEK). We assessed how corneal shape predicts hyperopia after triple DMEK. Retrospective cohort study. Patients with Fuchs endothelial corneal dystrophy (FECD) with Scheimpflug examinations before uncomplicated triple DMEK at a tertiary referral center were included. The arithmetic error was calculated (stable postoperative refraction minus predicted refraction). Using multinomial logistic regression, risk ratios of > +0.5 diopter (D) hyperopic and > 0.5 D myopic arithmetic errors were calculated. In 112 eyes, the median predicted refraction was -0.43 D (interquartile range [IQR], -0.47 to -0.17) with an achieved refraction of -0.63 to 0.56 (IQR). The arithmetic error was 0.34 D (IQR, -0.22 to 0.81). A hyperopic arithmetic error was present in 46% of eyes. FECD eyes with an oblate posterior cornea (Q value >0) had a 3.0 times higher risk of hyperopic shift after triple DMEK (95% confidence interval [CI], 1.3-7.0; P = .011), compared to spherical or prolate corneas (Q value ≤ 0). In eyes with posterior Q > 0, the mean prediction error was +0.50 D higher than in eyes with negative Q values (95% CI, 0.19-0.82; P = .002), independent of corneal thickness. Hyperopic surprises after triple DMEK particularly occur in corneas that are flatter centrally than the periphery because of edematous changes (oblate posterior profile). Eyes with a positive Q value on Scheimpflug imaging should be considered for additional power at the intraocular lens level.