Corneal Transplant Approaches Have Similar Effect on Refractive Power

Sustained steepening in posterior corneal curvature with loss in total corneal power can contribute to hyperopic shifts following endothelial keratoplasty in patients with endothelial dysfunction, according to findings published in the American Journal of Ophthalmology. Researchers say these changes in corneal measurements do not differ between those who underwent Descemet membrane endothelial keratoplasty (DMEK) and those who received ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK).

The researchers conducted a post-hoc subanalysis of the randomized, outcome-masked, controlled Descemet Endothelial Thickness Comparison Trial (DETECT; ClinicalTrials.gov Identifier: NCT02373137) and compared changes in corneal power measurements after DMEK or UT-DSAEK in patients with endothelial dysfunction with patients who had Fuchs’ endothelial dystrophy or pseudophakic bullous keratopathy. 

The primary outcome of DETECT was best spectacle corrected visual acuity. At baseline and postoperative months 3, 6, 12, and 24, total corneal refractive power (TCRP) and anterior/posterior simulated keratometry were obtained using Scheimpflug imaging, and spectacle refractions were assessed at postoperative months 6, 12, and 24.

A total of 50 eyes of 38 patients (mean age, 68 years) with endothelial dysfunction from Fuchs’ endothelial dystrophy or pseudophakic bullous keratopathy were randomized (1:1) to undergo DMEK or UT-DSAEK.

The researchers found a mean hyperopic shift of TCRP from baseline to 12 months of 0.80±1.1 (P =.002) in the DMEK group and 0.69±0.84 (P <.001) in the UT-DSAEK group. They demonstrated that posterior corneal curvature (Km) steepened (more negative dioptric power) by 0.42±0.10 (P <.001) in the DMEK group and 0.54±0.09 (P <.001) in the UT-DSAEK group. 

The team also found that mean change in TCRP and posterior corneal curvature was not significantly different between the DMEK and UT-DSAEK groups (TCRP, P =.71; posterior Km, P =.0.36).

“Our findings support the concept that posterior corneal curvature plays the predominant role in TCRP hyperopic shift, and consequently, results in postoperative hyperopic shifts in a majority of eyes,” according to the researchers.

The study was limited by its small participant number, which may have affected the researchers’ ability to detect all relevant changes.

Reference

Chamberlain W, Shen E, Werner S, Lin C, Rose-Nussbaumer J. Changes in corneal power up to two years after endothelial keratoplasty: results from the randomized controlled DETECT trial. Am J Ophthalmol. Published online July 20, 2022. doi:10.1016/j.ajo.2022.07.009