Abstract
This case discussed a significant ocular side effect, bilateral keratitis, which could be induced by afatinib, an irreversible epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). We explored the disease progression of a 52-year-old, stage IV nasopharyngeal carcinoma male patient, who was under afatinib treatment and had experienced progressive bilateral eye dryness and tenderness on increasing afatinib from 40 mg every other day to 40 mg daily. Clinical examination noted bilateral visual acuity reduction, diffuse superficial punctate keratopathy in the right eye, and a central epithelial defect in the left eye. Seidel test results were negative for both eyes, with no corneal infiltration, lagophthalmos, anterior chamber cell precipitation, or retinal lesion. Symptoms subsequently resolved after reducing the frequency of afatinib used, along with intensive ocular hydration. In summary, this case highlighted afatinib's potential link to bilateral keratitis, and early afatinib dose adjustment with supportive medication could significantly reverse the condition.