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 ofinfection with herpes simplex virus, and within 7 days of onset;

3. Ulcer's stromal involvement < 120 micron, as indicated by anterior segment opticalcoherence tomography;

4. Informed consent signed by patient or legal guardian. Having the ability to complywith study assessments for the full duration of the study.

Exclusion Criteria:

1. Clinical signs of a cause other than herpes simplex virus for the epithelialkeratitis;

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 notaccepting anticoagulant therapy; An international normalized ratio greater than 3 inpatients 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 wouldinterfere with or serve as a contraindication to adherence to the study protocol orability to give informed consent;

19. Active immunological diseases;

20. History of allo-limbal transplantation, penetrating keratoplasty or anti-glaucomafiltering surgeries.