Corneal Shape Predicts Hyperopic Shift After Triple DMEK
The corneas of patients who have edematous changes (oblate posterior profile) and are flatter centrally than at the periphery have an increased occurrence of hyperopic refractory outcome after combined Descemet membrane endothelial keratoplasty and cataract surgery (triple DMEK), according to a retrospective cohort study involving 112 eyes.
The risk ratios of >+0.5 diopter (D) hyperopic and >0.5 D myopic arithmetic errors were calculated for patients with Fuchs endothelial corneal dystrophy before uncomplicated triple DMEK. Among the results:
- The median predicted refraction was −0.43 D.
- The arithmetic error was 0.34 D.
- 46% of eyes had a hyperopic arithmetic error.
- An oblate posterior cornea (Q value > 0) was associated with a 3-fold higher risk of hyperopic shift after triple DMEK, compared to non-oblate corneas (Q value ≤ 0).
- Compared to eyes with negative Q values, eyes with posterior Q > 0 had a mean prediction error 0.50 D higher, and this was independent of corneal thickness.
The authors concluded that additional power at the intraocular lens level should be considered for eyes with a positive Q value on Scheimpflug imaging.
Fritz M, Grewing V, Böhringer D, et al. Avoiding Hyperopic Surprises After Descemet Membrane Endothelial Keratoplasty in Fuchs Dystrophy Eyes by Assessing Corneal Shape. American Journal of Ophthalmology. 2019;197:1-6. doi: 10.1016/j.ajo.2018.08.052.
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