An overpopulation of Demodex mites can cause chronic blepharitis, conjunctivitis, corneal inflammation and meibomian gland dysfunction. Tea tree oil, one known treatment, can cause irritation and allergic reactions. Another treatment—ivermectin—is well known for reducing the number of Demodex organisms, and researchers wanted to dive deeper and evaluate its efficacy in combination with eyelid hygiene treatment. 

In this retrospective case-control study, eyes of 102 patients with symptomatic Demodex blepharitis were divided into two groups according to the use of topical ivermectin. The ivermectin group applied the topical agent on the eyelashes for 15 minutes once weekly; controls group did not. In both groups, lid hygiene was performed once daily. During follow-up visits, the Standard Patient Evaluation of Eye Dryness (SPEED) symptom questionnaire score, Oxford staining score, eyelid debris, eyelid redness/swelling and telangiectasia were assessed.

The SPEED score and eyelid debris grade were significantly improved in both groups during the follow-up, although the SPEED score and eyelid debris grade showed greater changes in the ivermectin group than in the control group. The Oxford staining score, eyelid redness/swelling grade and telangiectasia grade were significantly improved only in the ivermectin group.

The authors noted that previous studies have shown that topical tea tree oil lid scrub reduced the average number of Demodex mites and improved symptoms and signs of Demodex blepharitis.

“In this study, no changes in eyelid redness/swelling or eyelid telangiectasia in the control group after using the eyelid cleansing product that contains tea tree oil were noted, although symptoms and eyelid debris grade were improved during the follow-up,” the authors explained in their study. The symptom score and eyelid debris grade were significantly milder in the control group; at the follow-up visit, score for the control group were similar or worsened relative to the ivermectin group.

The authors concluded that topical ivermectin combined with with daily eyelid hygiene was more effective than the lid-cleaning regimen only. “Based on these results, it is believed that a combination of topical ivermectin 1% cream and eyelid hygiene can be prescribed as an effective treatment for Demodex blepharitis.”

Choi Y, Eom Y, Gyn Yoon E. Efficacy of topical ivermectin 1% in the treatment of Demodex blepharitis. Cornea. 2021; 00:1-8.