Outcomes & Complications Of Descemets Membrane Endothelial Keratoplasty Without Routine Peripheral Iridotomy

Tamponade with air and gas is an essential step in Descemet’s membrane endothelial keratoplasty (DMEK) to help with graft attachment. To prevent associated complications such as pupillary block (PB), many surgeons across the globe perform peripheral iridotomy (PI) either before or during surgery. However, despite this pupillary block may occur and air / gas may have to be released. Further, PI is not without complications. The aim of this study is to report and analyse the outcomes and complications of DMEK performed without PI in patients with Fuch’s endothelial dystrophy using a standardised operative protocol.

This was a retrospective clinical audit conducted at a tertiary care eye hospital, and was approved by the local audit committee. 

All patients who underwent DMEK or DMEK in combination with phacoemulsification (DMEK triple) for Fuch’s Endothelial Dystrophy, either performed or supervised by a single surgeon using standardised operative protocol between Aug 2016 to July 2021 were included. Previous glaucoma surgery or previous laser PI were excluded, so were patients with aphakia or complicated pseudophakia. Primary outcomes were incidence of pupillary block (PB), graft detachment (GD), re-bubbling rates. Secondary outcomes were uncorrected distance visual acuity (UCDVA), best corrected distance visual acuity (BCDVA) and endothelial cell loss (ECL) at 6 months. Data was collected in a spreadsheet (Microsoft Excel 2021) and was analysed using Statplus software.

A total of 105 eyes were included. Mean age was 71.04+10.05 years. Twenty eight eyes were pseudophakic & underwent DMEK, remaining were phakic & underwent DMEK triple (n=77). For tamponade, either air (n=27) or SF6 gas (n=78) was used. PB including angle closure due to dislocation of bubble occurred in 5 eyes (4.8%). GD including small peripheral detachments was present in 52 eyes (50%); however, only 35 eyes required rebubbling (33%; 29-slit-lamp, 6-theatre). GD did not vary with type of surgery or surgeon grade, but was significantly worse with air (P<0.05); however, rebubbling rates and incidence of PB were similar between these three sub-groups. UCDVA, BCDVA and ECL at 6 months was 0.28+0.26, 0.20+0.27 and 40.46+20.36% respectively.

We report results of DMEK performed without routine PI, wherein incidence of pupillary block compares to that reported in previous studies. Rates of graft detachment, rebubbling and endothelial cell loss are not higher than reported in literature. Further, no significant difference between complications rates between type of surgery and surgeon, emphasizes importance of following standardised protocol. Use of SF^ gas for tamponade resulted in better graft attachment with no increased risk of pupillary block.