Low-concentration homogenized castor oil eye drops for noninflamed obstructive meibomian gland dysfunction

Abstract

Objective We developed low-concentration homogenized castor oil eye drops for the treatment of patients with noninflamed obstructive meibomian gland dysfunction (MGD), a major cause of lipid-deficiency dry eye, and assessed the safety, stability, and efficacy of the eye drops. Design Randomized, double-masked, placebo-controlled crossover clinical trial. Participants Forty eyes of 20 patients with noninflamed MGD. Methods After a preliminary study of eye drops containing castor oil, 2% castor oil and 5% polyoxyethylene castor oil (emulsifier) were mixed to formulate homogenized oil eye drops. The patients were assigned randomly to receive oil eye drops or placebo six times daily for 2 periods of 2 weeks each. Main outcome measures At the end of each treatment period, we assessed symptoms, tear interference grade, tear evaporation, fluorescein and rose bengal scores, tear break-up time (BUT), and meibomian gland orifice obstruction. Safety and stability tests were also performed. Results Symptom scores, tear interference grade, tear evaporation test results, rose bengal scores, tear BUT, and orifice obstruction scores after the oil eye drop period showed significant improvement compared with the results after the placebo period. No complications attributable to the eye drops were observed. The oil eye drops were stable when stored at 4°C. Conclusions The results indicate that castor oil eye drops are effective and safe in the treatment of MGD. The possible mechanisms of this treatment are improvement of tear stability as a result of lipid spreading, ease of meibum expression, prevention of tear evaporation, and the lubricating effect of the oil eye drops.