Potential Role and Significance of Ocular Demodicosis in Patients with Concomitant Refractory Herpetic Keratitis

PURPOSE: To evaluate the role of Demodex infestation of the eyelids in patients with recurrent herpetic keratitis. PATIENTS AND METHODS: This is a retrospective and noncomparative case series. Twenty-seven patients with ocular demodicosis and recurrent herpetic keratitis under conventional treatments were enrolled. Demographic data and clinical photographs were collected. Ocular demodicosis was confirmed by eyelash examination under a microscope. Eyelid scrub was initiated in these patients after proving Demodex infestation. Response after treatment was reviewed. RESULTS: Herpetic keratitis was characterized by epithelial defect, including dendritic lesions (seven eyes, 25.9%), geographic ulcer (three eyes, 11.1%), and neurotrophic ulcer (two eyes, 7.4%), associated with stromal involvement in 12 cases. Six cases with stromal reactivation, including disciform keratitis (two eyes, 7.4%), immune ring (three eyes, 11.1%), and ghost vessel (one eye, 3.7%), presented no epithelial defect. Active anterior uveitis with keratic precipitates was found in 15 cases. Demodex blepharitis was diagnosed with cylindrical dandruff along their lashes in all patients. Other ocular findings include meibomian gland dysfunction (15 eyes, 55.6%), mal-aligned lashes (eight eyes, 29.6%), telangiectasia (14 eyes, 51.9%), conjunctivitis (18 eyes, 66.7%), and ocular rosacea (three eyes, 11.1%). Initial unstable clinical presentations showed deterioration of corneal melting into descemetocele, corneal perforation, recalcitrant stromal infiltration/uveitis, and uncontrollable IOP, despite antiherpetic medication. After treatment of Demodex blepharitis, infestation was under control, followed by subjective improvement of ocular symptoms and a stable clinical outcome. CONCLUSION: Ocular demodicosis should be considered in patients with unstable recurrent herpetic keratitis. A prompt diagnosis and appropriate treatment may curb the progression of herpetic corneal infection.