# A Rare Case of Secondary Angle Closure Glaucoma Due to Soemmering’s Ring in a Pseudophakic Eye: The Role of Ultrasound Biomicroscopy

## TL;DR

A rare case shows how a Soemmering’s ring can cause angle closure glaucoma in a pseudophakic eye, highlighting the importance of ultrasound biomicroscopy for diagnosis.

## Contribution

Demonstrates a non-pupillary block mechanism of angle closure involving Soemmering’s ring and zonular instability in pseudophakic eyes with PEX.

## Key findings

- Soemmering’s ring enlargement and zonular instability caused anterior displacement of the iris-lens complex.
- Ultrasound biomicroscopy identified the atypical angle closure mechanism not visible with standard imaging.
- Surgical intervention was required despite patent iridotomies and maximal medical therapy.

## Abstract

Secondary angle closure glaucoma in pseudophakic eyes is uncommon. Soemmering’s ring, a circumferential proliferation of retained lens material, can, under certain conditions, lead to significant anterior segment distortion and angle closure. Pseudoexfoliation syndrome (PEX) can contribute, through zonular instability and chronic subclinical inflammation, to the anterior displacement of the capsular bag and iris-lens diaphragm. A 70-year-old male with a history of bilateral phacoemulsification presented with progressive visual decline and mild ocular discomfort in the left eye. Slit-lamp examination revealed pseudoexfoliation material on the pupillary margin and a markedly shallow anterior chamber. Intraocular pressure (IOP) was 35 mmHg, and best-corrected visual acuity was 20/100. Despite two patent laser peripheral iridotomies and maximal topical/systemic IOP-lowering therapy, the IOP remained elevated, and the angle remained narrow. Anterior segment optical coherence tomography (AS-OCT) showed anterior bowing of the iris without signs of pupillary block. Ultrasound biomicroscopy (UBM) revealed a 360-degree hyperechoic structure, consistent with an enlarged Soemmering’s ring, in direct contact with the posterior iris surface. The findings indicated a non-pupillary block mechanism of angle closure, likely driven by zonular laxity and capsular displacement. Surgical intervention was eventually required. This case highlights an uncommon but clinically significant mechanism of secondary angle closure in pseudophakic eyes with PEX. Enlargement of a Soemmering’s ring, in combination with zonular instability, can lead to anterior displacement of the iris-lens complex and persistent angle closure, even in the presence of a patent iridotomy. UBM is essential in identifying such atypical mechanisms and guiding effective treatment strategies.