Abstract： A 43-year-old female complained of repeated redness and pain in her left eye for more than 4 years,accompanied by blurred vision for more than 2 years.The diagnose of recurrent corneal epithelial erosion was considered in combination with the previous trauma of corneal scratch in her left eye and the history of myopia laser correction surgery.Subsequently,the patient developed a grayish-white lesion in the central cornea of the left eye with unclear boundaries and misty corneal stromal edema,but the pathogen tests were negative.The symptoms improved after empirical anti-bacterial and anti-fungal treatment,but repeated after COVID-19 infection,presenting the characteristics of viral keratitis.The diagnostic treatment relieved symptoms,yet the manifestations of corneal surface necrosis and satellite lesions appeared again.The patient was admitted for corneal debridement biopsy.The necrotic tissue taken during the operation was sent for metagenomic detection.The infection of Mycobacterium was identified.After the operation,topical amikacin and gatifloxacin were administered and the keratitis was finally controlled.In conclusion,the clinical manifestations of Mycobacterium keratitis have certain camouflage,and we should be vigilant about the non-tuberculous mycobacterium for atypical cases of keratitis with a history of myopia laser surgery.Metagenomic detection can be used for early diagnosis when routine pathogen examination fails to identify the pathogen.For non-tuberculous mycobacterium keratitis,a full course of topical treatment with sensitive antibiotics should be administered in sufficient dosage,with the caution of avoiding of side effects.If necessary,corneal flap excision can be conducted as adjuvant therapy.