New findings recently published in Contact Lens and Anterior Eye evaluated the safety and efficacy of topical ivermectin 1.0% cream to treat ocular demodicosis.
Give me some background first.
While Demodex mites—which live primarily within hair follicles and sebaceous glands—are a natural and necessary symbiont of humans, overpopulation (demodicosis) can result in conditions such as rosacea and Demodex blepharitis.
How is ocular demodicosis treated?
Current therapies for ocular demodicosis include tea tree oil-based treatments and the recently FDA-approved XDEMVY—a topical ophthalmic solution with lotilaner that targets parasite-specific GABA-Cl channels to eliminate mites.
Tell me more about topical ivermectin.
Topical ivermectin, an antiparasitic drug that was FDA-approved to treat Demodex infestation in rosacea patients, is currently an off-label treatment for ocular demodicosis.
Ivermectin reduces the impact of Demodex mites by binding to glutamate-gated chloride ion channels required for neurotransmission, causing paralysis and death of the mites.
Now, talk about the study.
In this retrospective, single-center study, investigators examined the efficacy of topical ivermectin 1.0% cream applied nightly to the lid margins of both eyes for 3 months.
The research team assessed ocular surface health at baseline when the treatment was prescribed and followed up at 3 and 12 months after baseline to measure whether improvements were sustained after treatment.
Talk about the cohort.
In total, investigators analyzed the treatment outcomes of 75 patients (mean age: 66.6±13.9, 44 females) with ocular demodicosis.
How was ocular surface health evaluated?
Investigators performed slit lamp biomicroscopy to take digital images of the upper eyelid lashes.
Manual image analysis with ImageJ—a Java-based image processing program—was conducted by a masked assessor to quantify signs of ocular demodicosis, such as the number of lashes with:
- Collarettes
- Visible Demodex tails
- Follicle pouting
Findings?
Of note, the number of lashes with collarettes (median [interquartile range (IQR)] 8 [4-13] at baseline) decreased with treatment (median [IQR] 0 [0-2] at the final visit, p<0.001).
Investigators observed a similar trend in the number of lashes with follicle pouting (median [IQR] 3 [1-5] at baseline) following treatment (median [IQR] 0 [0-1.8] at the final visit, p<0.001).
Anything else?
Any sign of lashes with visible tails was eliminated by the final visit (p<0.007).
Further, the fluorescein staining severity score also improved, particularly from baseline (median [IQR] 1 [0-2]) to the second visit (median [IQR] 0 [0-1], p<0.001).
No serious side effects were observed in any of the patients, with only mild irritation reported.
Expert opinion?
The study authors noted that lash follicle pouting—a sign thought to be specific to ocular demodicosis but not often reported—may provide an additional measure to evaluate the efficacy of the treatment.
They noted, “A potential benefit of assessing lash pouting is that it is an assessable sign in patients who may still have high Demodex load but have a low number of collarettes due to good lid hygiene.”
Take home.
These findings demonstrate the potential safety and efficacy of a 3-month course of topical ivermectin 1.0% cream to treat ocular demodicosis as measured by reduction in collarettes, follicle pouting, and visible Demodex tails.
In addition to alleviating the Demodex load, topical ivermectin was also effective in ameliorating ocular surface health, as shown by the improvement in fluorescein staining severity scores.
Lastly, as repeated applications are likely necessary to improve ocular demodicosis, the convenience of the at-home treatment outlined in this study offers clinicians and patients a more convenient and economical intervention.
Next steps?
Further studies to identify optimal treatment duration and improve diagnosis, management, and monitoring of ocular demodicosis are warranted, as it is often overlooked or misdiagnosed.