Impact of Iridotomy/Iridectomy Size on Postoperative Pupillary Block and Dysphotopsia Following DMEK

Descemet membrane endothelial keratoplasty (DMEK) is the standard surgical treatment for corneal endothelial disorders. A postoperative pupillary block may occur despite routine preoperative laser iridotomy or intraoperative surgical iridectomy. Insufficient size or incomplete patency of the iridotomy/iridectomy (IT) may contribute to this complication, while excessively large openings may be associated with postoperative dysphotopsia. This prospective observational study investigates the association between IT size measured by anterior segment optical coherence tomography (AS-OCT) and the occurrence of postoperative pupillary block and dysphotopsia after DMEK.

Study Overview

• Status: Not yet recruiting
• Conditions: Dysphotopsia; Descemet Membrane Endothelial Keratoplasty (DMEK); Pupillary Block After DMEK; Laser Iridotomy / Surgical Iridectomy
• Intervention / Treatment: Diagnostic test: Anterior Segment Optical Coherence Tomography (AS-OCT); Other: Dysphotopsia Questionnaire

Detailed Description

Descemet membrane endothelial keratoplasty (DMEK) represents the current standard procedure for surgical treatment of corneal endothelial diseases. During DMEK, a gas bubble is placed in the anterior chamber to attach the graft. In rare cases, this may lead to postoperative pupillary block with acute intraocular pressure elevation and severe pain. To prevent this complication, preoperative Nd:YAG laser iridotomy or intraoperative surgical iridectomy is routinely performed. Nevertheless, pupillary block continues to occur in a subset of patients.

One potential cause is an iridotomy or iridectomy that is too small or not fully patent, which may be misclassified as open on slit-lamp examination. Conversely, large iridotomy openings may induce postoperative dysphotopsia. Currently, no standardized recommendations exist regarding optimal IT size in the setting of DMEK, and systematic data correlating IT size with pupillary block and dysphotopsia are lacking.

This study is designed as a prospective, monocentric, non-interventional observational study. Adult patients undergoing DMEK at the Department of Ophthalmology, University Hospital Leipzig, with either preoperative laser iridotomy or intraoperative surgical iridectomy are invited to participate. AS-OCT imaging of the iris is performed preoperatively or postoperatively as an additional study-related diagnostic procedure to quantify IT size. All surgical procedures and clinical follow-up examinations remain unchanged from standard care.

Postoperatively, clinical outcomes including the occurrence of pupillary block are documented during routine follow-up. New postoperative dysphotopsia is assessed using a structured, German-adapted dysphotopsia questionnaire based on the instrument described by Vera et al., administered after resolution of the intracameral gas bubble and corneal edema.

The primary endpoint is the occurrence of postoperative pupillary block after DMEK. The secondary endpoint is the occurrence and severity of new postoperative dysphotopsia. A total of 100 consecutive patients will be included over a planned study period of 12 months. The study aims to explore associations between IT size and postoperative complications in order to improve perioperative risk stratification in DMEK surgery.

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: Christian Girbardt, Dr. med.; Phone Number: +493419721650; Email: christian.girbardt@medizin.uni-leipzig.de

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult patients undergoing Descemet membrane endothelial keratoplasty (DMEK) for corneal endothelial disease at the Department of Ophthalmology, University Hospital Leipzig, in whom a preoperative laser iridotomy or intraoperative surgical iridectomy is performed as part of standard care.

Description

Inclusion Criteria:

• Adults aged ≥ 18 years

Patients undergoing Descemet membrane endothelial keratoplasty (DMEK) at the Department of Ophthalmology, University Hospital Leipzig

Preoperative Nd:YAG laser iridotomy or intraoperative surgical iridectomy performed as part of standard care

Ability to provide written informed consent

Willingness to complete the postoperative dysphotopsia questionnaire

Exclusion Criteria:

• Inability to provide informed consent or refusal to participate

Pre-existing surgical iridectomy

Missing or incomplete preoperative or postoperative anterior segment OCT data

Active anterior uveitis or panuveitis at the time of surgery

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence of postoperative pupillary block after DMEK	Pupillary block is defined as intraocular pressure >25 mmHg with a centrally deep anterior chamber and partial or complete peripheral angle closure.	Within the first five postoperative days, including day 0 (date of surgery)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence and severity of postoperative dysphotopsia	Assessed using a structured dysphotopsia questionnaire based on the instrument by Vera et al., providing an ordinal severity score.	between 2 weeks and 1 year postoperatively

Collaborators and Investigators

• Sponsor: University of Leipzig

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): July 1, 2027

Study Registration Dates

• First Submitted: January 26, 2026
• First Submitted That Met QC Criteria: May 4, 2026
• First Posted (Actual): May 11, 2026

Study Record Updates

• Last Update Posted (Actual): May 11, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: DMEK-YAG

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No