'Photopsia' describes the symptom of visual disturbances that are typically flash-like, sudden in onset and brief, and occurring without light entering the eye. Patients reporting photopsia often pose a diagnostic challenge, given the wide range of possible neurological and ophthalmological causes. We review the common causes of photopsia, discuss the assessment and workup of this symptom, and stress the importance of close interdisciplinary liaison to help with its diagnosis and management. We discuss a patient with acute zonal occult outer retinopathy to illustrate these points.