Purpose:To investigate the effects of topical cyclosporine A 0.05%, cyclosporine A 2%, epinastine hydrochloride 0.05%, and prednisolone acetate 1% in an experimental allergic conjunctivitis model.Methods:Forty Wistar albino male rats were randomly divided into 5 groups. All the rats were immunized by an intraperitoneal injection of 100 g of ovalbumin. After 2 weeks, topical treatment was administered: cyclosporine A 0.05% 4 times a day to group 1, cyclosporine A 2% 4 times a day to group 2, epinastine HCl 0.05% 2 times a day to group 3, and prednisolone acetate 1% 4 times a day to group 4 for the following 7 days. Group 5 was designated as the control group. Both eyes of the rats were enucleated on the 22nd day of the study. The excised sections were stained by toluidine blue for mast cell count and by hematoxylin-eosin for histopathological evaluation.Results:The 2 solutions of cyclosporine A and epinastine were more effective than prednisolone acetate (P < 0.05) when compared with the control in histopathological scoring. There were statistically significant differences between the treatment groups and the control group (P < 0.05); however, no differences were observed between the treatment groups in the mast cell number.Conclusions:Topical 0.05% cyclosporine A is as effective as 2% cyclosporine A and epinastine in suppressing mast cell-mediated type I allergic conjunctivitis in an experimental allergic conjunctivitis model.