Impact of preoperative visual acuity on Descemet Membrane Endothelial Keratoplasty (DMEK) outcome

To evaluate whether and how preoperative visual acuity predicts visual acuity outcome after Descemet Membrane Endothelial Keratoplasty (DMEK).

One thousand eighty-four out of 1162 consecutive eyes having undergone DMEK alone or combined with cataract surgery (triple-DMEK) between July 2011 and February 2016 from the prospective Cologne DMEK database were included and analyzed retrospectively for correlations between pre- and postoperative visual acuity values at 1, 3, 6, and 12 months after transplantation.

There is a significant correlation between pre- and postoperative visual acuity (VA) after (triple)-DMEK after 6 and 12 months (p = 0.005 and p = 0.011 respectively; Pearson's correlation coefficient 0.240 and 0.224). Preoperative VA below 20/100 leads to delayed and reduced final visual acuity results after 12 months (p < 0.001). However, defining an increase in VA > 0.1 logMAR as clinically relevant, we could not show any clinically relevant significant difference in the time needed to recover to final VA and in final VA. There is no significant difference for preoperative VA values above 20/40. The chance to reach postoperative VA above 20/25 is 40% for preoperative VA of 20/200, 50% for preoperative VA of 20/60 and > 60% for preoperative VA of 20/40.

DMEK results in very good final postoperative visual acuity results even in eyes with very poor preoperative vision caused by corneal pathology. However, preoperative visual acuity values below 20/100 result in significantly poorer visual recovery, which suggests that there is benefit in performing surgery early enough before this value is reached. Preoperative visual acuity seems to be an adjuvant tool for the prediction of the final visual outcome after DMEK.