[Iridoschisis: a rare condition].

Abstract

Iridoschisis, a rare degenerative condition, is defined by atrophy of the iris associated with cleavage of the iris stroma, the anterior part of which disintegrates into fibrils floating in the Anterior chamber (AC). Iris involvement is bilateral, progressive but not transfixing, respecting the pigment epithelium and often localised in the lower sector. Diagnosis is clinical. Optical coherence tomography of the anterior segment (OCT-SA) provides characteristic semiological features. The main differential diagnoses are irido-corneo-endothelial syndrome and Axenfeld-Rieger syndrome. Association with angle-closure glaucoma (ACG) is reported in 2/3 of cases. The mechanism of hypertonia is thought to be twofold: failure of the trabecular meshwork to evacuate Aqueous humour (AH) through iris debris and resistance of the iridolenticular interface to the flow of AH, resulting in pupillary block. A 71-year-old patient with no previous pathological history consulted for a red and painful left eye in connection with an acute angle-closure crisis. After resolution of the crisis by hypotonising treatment, examination showed a narrow CA (A), an atrophic iris inferiorly cleaved into fibrils floating in the HA (B). Gonioscopy showed a closed Iridocorneal angle (ICA) in the absence of anterior synechiae. OCT-SA showed cleavage and disorganisation with a mottled appearance of the anterior part of the iris stroma respecting the iris pigment epithelium (C), a closed ICA and a narrow CA (D). All these features supported the diagnosis of iridoschisis associated with an AFM crisis.