Author: Tay Xue Chao Brian Diaz / Editor: Thomas MacMahon / Reviewer: Anoop Chidambaram / Codes:  OptC1, OptP3, OptP4, OptP5, SLO1  / Published: 09/12/2023

Your next patient is a 60-year-old lady presenting with rapid onset severe unilateral eye pain, blurry vision, and headache. She also describes seeing rainbow-coloured halos around bright lights. Just as you are about to commence your examination, she vomits on the floor and apologises profusely as soon as she catches her breath.

While reassuring her, you observe her affected eye and make a spot diagnosis.