The purpose of this study is to report a case of corneal epithelial defects resulting from topical treatment of blepharitis with tea tree oil (TTO).A 44-year-old man with a 1 year history of blepharitis non-responsive to eyelid hygiene was found to have signs of Demodex infestation. He was treated with a topical, off-label 50% TTO solution. Shortly afterward, the patient complained of bilateral ocular discomfort.Slit-lamp examination revealed conjunctival injection and a corneal epithelial defect in both eyes. Treatment with lubricant, antibiotic, and steroid eye drops as well as bandage contact lenses was required to facilitate corneal healing.Topical use of off-label, 50% concentration TTO can result in corneal epithelial defects. Eye care professionals should remain aware of this risk and only use approved, low-concentration TTO products when treating Demodex-related blepharitis.