Patient: 24-year-old woman Chief Complaint: Red, painful eye with decreased vision History of Present Illness: The patient presents to the emergency department with severe pain, redness, and tearing in her right eye that began 2 days ago. She reports blurry vision and a foreign body sensation. The symptoms have progressively worsened despite the use of over-the-counter eye drops. She denies trauma to the eye but mentions that she routinely wears contact lenses, often sleeping with them overnight. There is no history of discharge from the eye, photophobia, or systemic symptoms like fever. Past Medical History: No significant past illnesses; No history of autoimmune diseases Medications: Occasional use of lubricating eye drops; No other medications Allergies: None Social History: Works as a barista, wears contact lenses daily; No smoking or alcohol use Physical Examination: General: Alert, no systemic signs of illness Right eye: Conjunctival injection Corneal opacity/white infiltrate seen in the central cornea Purulent discharge noted Positive fluorescein stain: Large area of epithelial defect Mild hypopyon present (pus in the anterior chamber) Normal pupil size and reactivity Left eye: Normal Visual Acuity: Right eye: 20/80 Left eye: 20/20 Slit-lamp examination: Confirms corneal ulcer with stromal involvement and associated inflammation. Which of the following is the most likely cause of his corneal ulcer?
