A double-masked study to compare the efficacy and safety of topical cromolyn for the treatment of allergic conjunctivitis

Background/PurposeTo compare the efficacy and safety of topical cromolyn between with and without preservative for the treatment of allergic conjunctivitis.MethodsA 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.ResultsA 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.ConclusionCromolyn 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.