Ultrabiomicroscopy To Identify Retinal Vascular Occlusion Cause : A Case Report

Retinal vein occlusion (RVO) is a sight-threatening disorder considered to be the second morbidity in microvascular disease. An increased risk of RVO has been associated with a history of glaucoma.

One of the rare causes of acute angle closure and refractory glaucoma is the presence of primary iris cysts, that are benign lesions, mostly bilateral and asymptomatic.

In this case report, we describe the case of a young patient presenting with RVO that led to the diagnosis of refractory glaucoma secondary to bilateral iridociliary cysts.

The aim of our study is to underline the importance of recognizing iris cysts during glaucoma examination and the benefits of ultrasound biomicroscopy in patients presenting with creeping angle closure.

Groupe Hospitalier Mulhouse Sud Alsace, Hôpital Emile Muller, Ophthalmology clinic.

We report the case of a 34 years old patient who presented to the emergencies with a complaint of loss of vision in the left eye. Visual acuity was 0.2 decimal in the affected eye versus 1.0 on the right eye, and anterior segment examination found a narrow anterior chamber, and the fundoscopy revealed a central retinal vein occlusion (CRVO). Ocular tonus was 28mmhg and 35mmhg in the right and left eye respectively. The patient was initially treated with glaucomatous drops and a cardiovascular work up that was prescribed returned unremarkable. Further imaging to explore the ocular hypertension showed a closed angle on gonioscopy, altered RNFL on the papillary OCT of the affected eye, and a large deficit in campimetry. UBM showed the presence of multiple iridociliary cysts bilaterally, responsible of a plateau iris configuration. A peripheral laser iridectomy was performed and close follow-up showed no improvement of visual acuity confirming that glaucoma caused irreversible vision loss.

Glaucoma is a well-known risk factor for RVO, particularly for CRVO. In young  patients with no history of open angle or familial glaucoma, the presence of a shallow anterior chamber evokes an iris plateau configuration, often secondary to iris cysts in up to 38% of cases. The use of UBM identifies these cysts in otherwise asymptomatic patients in up to 54% of cases. Cysts larger than 0.8mm, found in the sulcus or multiple ones like our case are more subject to angle narrowing or closure.

Although rare and often asymptomatic, the early diagnosis of iridociliary cysts using UBM can be useful to prevent closed angle glaucoma and its potential complications. When presenting with retinal veinous occlusion signs, it is essential to do a thorough gonioscopy and if needed an UBM to rule out glaucoma as an original cause. This will help save vision in young asymptomatic patients.