Characterization and outcome following excision of masses in the nictitating membranes of horses: 50 cases (1998-2012).

Objective: To determine the histologic findings associated with masses in the nictitating membranes (third eyelids) of horses and to identify prognostic factors associated with recurrence and the outcome.

Design: Retrospective case series.

Animals: 50 horses with masses in a third eyelid.