AIM: To investigate the efficacy of optimal pulse technology(OPT)in the treatment of demodex blepharitis and its influence on ocular surface function.METHODS: A retrospective study was conducted from February 2018 to October 2020. A total of 127 patients(254 eyes)with demodex blepharitis were assigned to the observation group and the control group according to the treatment method. The control group(63 patients, 126 eyes)were given conventional hot compress, eye cleansing and drug therapy. On this basis, the observation group(64 patients, 128 eyes)was treated with OPT. Both groups were given 6wk of continuous treatment. Demodex count, Marx's line scores, meibum character scores, ocular surface disease index(OSDI)scores, non-invasive tear break-up time(NIBUT), non-invasive tear meniscus height(NITMH)and lipid layer thickness(LLT)were compared between the two groups, and safety was evaluated.RESULTS: After 6wk of treatment, demodex count, Marx's line scores, meibum character scores and OSDI scores of the two groups decreased. NIBUT, NITMH and LLT increased. Meanwhile, demodex count, Marx's line scores, meibum character scores and OSDI scores of the observation group were significantly lower than those in the control group. NIBUT, NITMH and LLT were longer/larger than those in the control group(P<0.001). No obvious abnormality of intraocular pressure or conjunctival/corneal injury was observed in either group.CONCLUSION:OPT is effective and safe in the treatment of demodex blepharitis.