14th August 2020

A 27-year old man presents with a one day history of a painful left red eye which is worsened by bright lights

A 27-year old man presents with a one day history of a painful left red eye which is worsened by bright lights. He has no headache or neck stiffness. Visual acuity is reduced in the left eye compared to the right. His past medical history is significant for ankylosing spondylitis. 

For the patient above, please select the SINGLE most likely diagnosis. Select ONE option from the list above.