Grade 1: anterior uveitis with trace cells 

Grade 2: anterior uveitis with 1+ or 2+ cells 

Grade 3: anterior uveitis with 3+ or greater cells; intermediate posterior or pan-uveitis

Grade 4: best corrected visual acuity of 20/200 or worse in the affected eye 

Reference: Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 Published: November 27, 2017