 After anesthetizing the eye with medication, the conjunctiva may be moved with a cotton swab to observe the location of the enlarged blood vessels.In very rare cases, if episcleritis does not respond to treatment, then a biopsy may be considered, which help provide information regarding any underlying condition (granulomatosis with polyangitis, vasculitis, etc).However, a biopsy is not routinely necessary in the diagnosis of episcleritis.