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William Bradley Wainright, Ryan McNabb, Alan Carlson, Terry Kim, Natalie A Afshari, Anthony N Kuo; Relationship between Hyperopic Shift after DSAEK and Corneal Anterior Curvature, Posterior Curvature, and Thickness. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2702.
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© ARVO (1962-2015); The Authors (2016-present)
A hyperopic shift is known to occur after corneal endothelial keratoplasty (EK). Possible sources for the postoperative refractive shift include anterior curvature flattening, corneal deswelling, and/or posterior curvature steepening. The purpose of this study was to determine the relationship between hyperopic shift after Descemet’s stripping automated EK (DSAEK) and corneal curvatures and thickness.
Subjects undergoing DSAEK alone (17 eyes) or with concurrent cataract surgery (DSAEK triple procedure) (13 eyes) at the Duke Eye Center were enrolled under IRB approval. Pentacam (Oculus, Wetzlar, Germany) imaging and manifest refraction (MRx) were performed preoperatively and at least 6 months postop. Pre to post DSAEK changes in corneal posterior curvature (delta Kp), anterior curvature (delta Ka), and central thickness (delta CCT) were calculated and each was t-tested for significance. Pre to post DSAEK changes in spherical equivalent MRx were calculated (delta MRx). For eyes undergoing DSAEK triple, target MRx was used for preop MRx. Univariable and multiple-regression analyses of delta MRx as a function of delta Kp, delta Ka, and/or delta CCT were performed.
Mean delta MRx from DSAEK was +0.670 ± 0.158 D (hyperopic shift), p=0.003. Mean delta Kp was -0.665 ± 0.132 D (hyperopic shift), p=0.00003. Mean delta Ka was -0.107 ± 0.077 D, p=0.184. A univariable linear regression model of delta MRx as function of delta Kp had correlation coefficient R= -0.54 and a significantly nonzero slope, p=0.002. A regression of delta MRx as a function of delta Ka had R= -0.40 with p=0.03. A regression of delta MRx as a function of delta CCT had R=0.03 with p=0.87. A multiple-regression analysis of delta MRx as function of delta Kp, delta Ka, and delta CCT had R=0.64. For this model, delta Kp had a statistically significant nonzero slope, p=0.005. The slopes for delta Ka (p=0.086) and delta CCT (p=0.13) were not significantly different from zero.
DSAEK causes a significant change in corneal posterior curvature that is associated with the postoperative hyperopic shift. There was no significant change in corneal anterior curvature after DSAEK. Deturgescence of the cornea from DSAEK also had no significant relationship to the hyperopic shift. Posterior curvature changes should be prioritized in developing clinical nomograms to account for post DSAEK refractive shifts.
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