A Double-Masked Study to Compare the Efficacy and Safety of Topical Cromolyn with Preservative to That without Preservative for the Treatment of Allergic Conjunctivitis

BACKGROUND/PURPOSE: To compare the efficacy and safety of topical cromolyn between with and without preservative for the treatment of allergic conjunctivitis. METHODS: A double- masked study was performed in patients with allergic conjunctivitis. Each cromolyn sodium 2% ophthalmic solution with or without 0.01% benzalkonium chloride (BAK) was randomized to apply on either eye. The efficacy and safety were evaluated every other week by a questionnaire about ocular itching, redness and foreign body sensation, and objective scores of conjunctival redness, chemosis, cornea erosion and discharge using slit-lamp biomicroscopy. An overall response was also rated by physician's impression. RESULTS: A total of 37 subjects were enrolled in this study but only 33 completed the study. All of subjective questionnaire scores showed a significant improvement after treatment in both groups. Objective score of redness significantly decreased after treatment in either groups but not chemisos or discharge. After 4-week treatment, corneal erosion diminished significantly in the group without preservative but not in the group with 0.01% BAK. There was no significant difference between with and without 0.01% BAK groups in each subjective or objective score. No adverse effect related with medication was observed. CONCLUSION: Cromolyn 2 % ophthalmic solution was effective and safe to treat allergic conjunctivitis. A short-term use of cromolyn 2 % ophthalmic solution with 0.01% BAK would not cause any significant toxicity in patients with allergic conjunctivitis. Preservative-free cromolyn may be beneficial to the compromised eyes or eyes required of long-term medication