Femtosecond Laser-assisted Corneal Debridement for Herpes Simplex Keratitis

Inclusion Criteria: 1. Aged between 18 and 80 years old; 2. Epithelial ulceration in a dendritic or geographic pattern, characteristic of infection with herpes simplex virus, and within 7 days of onset; 3. Ulcer's stromal involvement \< 120 micron, as indicated by anterior segment optical coherence tomography; 4. Informed consent signed by patient or legal guardian. Having the ability to comply with study assessments for the full duration of the study. Exclusion Criteria: 1. Clinical signs of a cause other than herpes simplex virus for the epithelial keratitis; 2. Antivirus or corticosteroid treatment within 6 months; 3. Active stromal keratitis or iritis; 4. History of allergy or adverse reaction to ganciclovir; 5. High myopia with a spherical equivalent of -15.0 D or less; 6. Corneal or ocular surface infection within 30 days prior to study entry; 7. Ocular surface malignancy; 8. Uncontrolled diabetes with most recent Hemoglobin A1c greater than 8.5%; 9. Renal failure with creatinine clearance\< 25ml/min; 10. Alanine aminotransferase \> 40IU/L, or aspartate aminotransferase \> 40IU/L; 11. Platelet levels \< 150,000 or \> 450,000 per microliter; 12. Hemoglobin \< 12.0 g/dL (male) or \< 11.0 g/dL (female); 13. Prothrombin time \> 16s and activated partial thrombin time \> 35s in patients not accepting anticoagulant therapy; An international normalized ratio greater than 3 in patients accepting anticoagulant therapy; 14. Pregnancy (positive test) or lactation; 15. Participation in another simultaneous medical investigation or clinical trial; 16. Severe cicatricial eye disease; Conjunctival scarring with fornix shortening; 17. Severe dry eye disease as determined by Schirmer's test \< 2mm at least in one eye; 18. Any medical or social condition that in the judgement of the investigator would interfere with or serve as a contraindication to adherence to the study protocol or ability to give informed consent; 19. Active immunological diseases; 20. History of allo-limbal transplantation, penetrating keratoplasty or anti-glaucoma filtering surgeries.