Peripheral Iridotomy-Less Approach in Descemet's Membrane Endothelial Keratoplasty Using Pupil-Dilating Eye Drops, a Retrospective Case-Control Study.

Abstract

Purpose: To assess clinical outcomes after Descemet's Membrane Endothelial Keratoplasty (DMEK) with mydriatic eye drops without peripheral iridotomy (PI-less). We performed a retrospective, observational clinical study to determine the postoperative intraocular pressure (IOP) changes and graft viability in a cohort of patients with Fuchs' endothelial corneal dystrophy (FECD) and bullous keratopathy (BK).

Patients and methods: Included in this study were 41 PI-less DMEK patients with 44 eyes (median age: 77 years; range: 53-88 years). Patients received either PI-less DMEK (group-1) or PI-less triple DMEK (group-2). The mean follow-up duration was 16 months. Eyes after standard DMEK or triple DMEK served as controls (n = 20). Included in the study were patients admitted to the hospital (securing IOP control), patients in which the tamponading agent was air or gas (SF6) and only patients with physiological air resorption, ie without routine, postoperative air/gas release (90% air/gas fill of the anterior chamber at end of surgery). Phakic eyes were not included. Postoperatively, mydriatic eye drops were administered for three days 4x/d (phenylephrine 25 mg/mL, tropicamide 5 mg/mL). The best-corrected visual acuity (BCVA), endothelial cell density (ECD), and IOP were assessed. Intra- and postoperative complications and management were recorded.

Results: BCVA improved significantly in both groups (group-1:0.90 ± 0.57 to 0.20 ± 0.23logMAR (p = 0.000); group-2:0.47 ± 0.23 to 0.17 ± 0.42logMAR (p = 0.0067). ECD decreased significantly: Group-1 2428±225 cells/mm² to 1810±236 cells/mm² (p = 0.005); group-2 2447 ± 178 cells/mm² to 1866 ± 229 cells/mm² (p = 0.012). After postoperative day-1 IOP decreased significantly: Group-1 p = 0.004 (10.0 ± 2.8 mmHg) and p = 0.002 (11.3 ± 3.1 mmHg); group-2 p = 0.002 (10.7 ± 3.6 mmHg) and p = 0.002 (11.4 ± 2.2 mmHg); for postoperative days 2 and 3, respectively. Postoperative adverse events included pupillary block necessitating emergency air release. Intergroup analysis did not show a significant difference in ECD, IOP (after postoperative day-1) and logMAR (after 6 months).

Conclusion: Patients may benefit from the promising results of the study regarding postoperative IOP developments and graft viability after DMEK using mydriatic eye drops (phenylephrine 25 mg/mL, tropicamide 5 mg/mL). PI-less triple DMEK in particular might improve accessibility, reduce surgical complexity, or lower costs, making it attractive in resource-limited settings. Close postoperative IOP monitoring is advised in PI-less DMEKs.