for people ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
completion around
Principal Investigator
by Thomas Lietman
Headshot of Thomas Lietman
Thomas Lietman



Steroids and Cross-linking for Ulcer Treatment (SCUT II) is an international, randomized, double-masked, clinical trial. The purpose of this study is to determine differences in 6-month visual acuity between medical antimicrobial treatments alone versus antimicrobial treatment plus collagen cross-linking (CXL), as well as to further evaluate findings from subgroup analyses of SCUT. Patients presenting to the Aravind Eye Care System (India), Kaiser Permanente Northern California (USA), or the University of California, San Francisco (USA) with smear-positive and/or culture-positive typical (i.e. non-Nocardia or Mycobacteria) bacterial corneal ulcers and moderate to severe vision loss, defined as Snellen visual acuity of 20/40 or worse, will be eligible for inclusion. Those who agree to participate will be randomized to one of three treatment groups:

Group 1: Standard therapy, topical 0.5% moxifloxacin plus topical placebo plus sham CXL Group 2: Early steroids, topical 0.5% moxifloxacin plus topical difluprednate 0.05% plus sham CXL Group 3: CXL plus early steroids, topical 0.5% moxifloxacin plus topical difluprednate 0.05% plus CXL


Keratitis Bacterial, Keratitis, Riboflavin, Moxifloxacin, Difluprednate, Moxifloxacin Ophthalmic, Difluprednate Ophthalmic, Riboflavin Ophthalmic, Early Steroids, Cross-Linking plus Early Steroids


You can join if…

Open to people ages 18 years and up

  • Corneal ulcer that is smear positive and/or culture positive (within 24 hours) for typical bacteria (i.e. non-Nocardia or Mycobacteria)
  • Moderate to severe vision loss, defined as Snellen visual acuity of 20/40 (6/12) or worse
  • Corneal thickness ≥350 µm, as measured on AS-OCT
  • Age over 18 years
  • Basic understanding of the study as determined by the physician
  • Commitment to return for follow up visits

You CAN'T join if...

  • Evidence of concomitant infection on exam, gram stain, or confocal microscopy (i.e. herpes, both bacteria and acanthameoba on gram stain)
  • Impending or frank perforation at recruitment
  • Involvement of sclera at presentation
  • Non-infectious or autoimmune keratitis
  • History of corneal transplantation or recent intraocular surgery
  • Pinhole visual acuity worse than 20/200 in the unaffected eye
  • Participants who are decisionally and/or cognitively impaired


  • Francis I. Proctor Foundaiton
    San Francisco California 94143 United States
  • University of Miami
    Miami Florida 33136 United States
  • Aravind Eye Care System
    Madurai Tamil Nadu India

Lead Scientist at UCSF

  • Thomas Lietman
    Professor, Proctor Foundation, Chancellor/EVC/FAS. Authored (or co-authored) 480 research publications


in progress, not accepting new patients
Start Date
Completion Date
Thomas M. Lietman
Phase 3 Bacterial Keratitis Research Study
Study Type
About 280 people participating
Last Updated