Efficacy of cyclic therapy with terpinen-4-ol in Demodex blepharitis

Purpose To describe the effectiveness of cyclic treatment with terpinen-4-ol, a tea tree oil component, on Demodex blepharitis. Methods The presence of Demodex was determined by eyelash rotation as proposed by Mastrota. Schirmer test, tear breakup time, ocular surface disease index, lid margin score, meibomian gland expressibility score, and Oxford grade were performed. Patients were advised to apply heat followed by terpinen-4-ol soaked wipes to eyelids twice a day for 2 weeks. At the end of 2 weeks, treatment was interrupted for 7–10 days. The same treatment was repeated once again. The patients were examined after the first and second cycle of treatment and after 1 year. Results There was a statistically significant improvement in Schirmer test (10.37 ± 4.73 and 13.13 ± 3.44 mm/5 min), tear breakup time (6.47 ± 3.31 and 7.6 ± 2.89 s), ocular surface disease index (47.94 ± 19.77 and 34.28 ± 13.40), lid margin score (3.2 ± 0.7 and 2.63 ± 0.71), meibomian gland expressibility scores (1.93 ± 0.64 and 1.4 ± 0.67), and Oxford grade (0.9 ± 0.8 and 0.5 ± 0.63) after the first cycle of treatment ( p < 0.05). The improvement in symptoms and tear function tests of the patients after the second cycle was significantly better than in pre-treatment levels. At 12-month follow-up, symptoms of two patients (93%) relapsed. Conclusion The administration of terpinen-4-ol to the eyelid margins in a cyclic manner in Demodex blepharitis is effective against adult and hatching Demodex and breaks the vicious cycle.