Surgery-induced iris abnormalities after Descemet membrane endothelial keratoplasty and their impact on postoperative clinical outcomes [Letter].

Dear editor

I have read with great interest the article by Mori et al1 on “Surgery-induced iris abnormalities after Descemet membrane endothelial keratoplasty and their impact on postoperative clinical outcomes” and I have a few concerns regarding the article.

Firstly, the authors should have graded the amount of iris damage on slitlamp examination. This would give more insight into the magnitude of iris damage and subsequent formation of peripheral anterior synechiae. This becomes even more important as the authors mention that no gonioscopy was performed in the study.

Secondly, it would have been more informative if the axial lengths of the eyes were mentioned as it is known that short axial lengths and iris damage are associated with iris posterior synechiae after DMEK.2 As the study population in this article is from Japanese eyes this becomes vital as Asian eyes are known to have short axial lengths and shallow anterior chamber depths.

Thirdly, the group with iris damage had less visual improvement than the group without iris damage. The amount of cystoid macular edema (CME) in the postoperative period is positively correlated to the amount of intra operative iris damage. The aqueous humor of those eyes may contain higher protein/cytokine levels, consistent with the “chronic pathological inflammation” theory which can lead to CME.3 This should been taken into account while analysing the visual outcomes in the iris damage group.