Case report of secondary angle closure glaucoma from a Soemmering's ring presenting with episodes of transient total monocular vision loss.

Purpose: To describe an interesting case of a Soemmering's ring causing intermittent secondary angle closure glaucoma presenting as painless transient monocular vision loss (TMVL). Observation: A 72-year-old male with a history of uncomplicated cataract surgery presented with episodes of TMVL in the right eye, lasting minutes, and without other associated symptoms. His initial intraocular pressure (IOP) was normal, and after neuro-ophthalmology assessment he underwent work-up for amaurosis fugax which was unrevealing. At follow up, the patient was found to have an IOP of 40 mmHg. Gonioscopic examination showed no visible angle structures and ultrasound biomicroscopy revealed a large Soemmering's ring and no pseudophacodonesis. Laser peripheral iridotomy (LPI) was performed resulting in return of IOP to the patient's baseline along with resolution of TMVL episodes. Conclusion and importance: We describe a rare presentation of painless recurrent TMVL resulting from secondary angle closure caused by a Soemmering's ring. This case highlights the importance of retaining intermittent IOP elevation on the differential diagnosis for TMVL.