Source: Zhongshan Ophthalmic Center of Sun Yat-sen University

Edited by: Liu Nian

Professor Lingyi Liang noticed an extraordinarily protruding iris collarette, as shown in the picture, in a patient with allergic conjunctivitis. Such raised iris collarette is considered a benign variation and asymptomatic. It might be caused by the unabsorbed pupillary membrane. It remains unclear whether such protruding iris collarette is a type of persistent pupillary membrane. The iris collarette is a landmark that separates the central pupillary zone from the peripheral ciliary zone. It is a raised, rippled ring of iris tissue that locates at 1.5-2mm to the pupil.

The iris collarette has been overlooked previously. However, in recent years, the morphology of iris has been implicated in iris recognition technique. Whether iris collarette also play a role in such technique warrants further investigation.