A 35-year-old woman presented to the Emergency Department with an acute, painless, dilated left pupil. Her medical history was notable for myopia and truncal herpes zoster infection that had completely resolved 2 years ago. Ocular history was significant for bilateral contact lens wear, and her preferred wetting and cleaning solution was Opcon-A (naphazoline and pheniramine). Her surgical, social, and family history and a complete review of systems were unremarkable. On examination, the visual acuity was 20/20 OU.