title: Safety and efficacy of simultaneous corneal collagen cross-linking with topography-guided PRK in managing low-grade keratoconus: 1-year follow-up.
abstract: OBJECTIVE
  To evaluate 1-year visual and topographic outcomes and safety and efficacy of corneal collagen cross-linking (CXL) combined with topography-guided photorefractive keratectomy (TG-PRK) to achieve near emmetropia in eyes with low-grade keratoconus.
  
  
  METHODS
  Twenty-two eyes from 15 patients (11 women, 4 men) were included in a prospective, nonrandomized, noncontrolled clinical study. Mean patient age was 26.6±6.07 years (range: 19 to 40 years). Inclusion criteria were low-grade keratoconus with evidence of progression, transparent cornea, corrected distance visual acuity (CDVA) 0.8 (decimal) or better, corneal thickness >440 μm, and maximum keratometry readings (K-max) <51.00 diopters (D). All patients underwent simultaneous TG-PRK with CXL. Study parameters were uncorrected distance visual acuity, CDVA, manifest refractive error, manifest and topographic (corneal) astigmatism, patient satisfaction, and efficacy and safety of the treatment. Follow-up was 1 year.
  
  
  RESULTS
  After 1 year, statistically significant improvement was noted in all study parameters (P<.01). The safety and efficacy indices were 1.6 and 0.4, respectively. Patient satisfaction questionnaire showed that 91% were satisfied, 9% were not completely satisfied but believed they improved, and none were dissatisfied. Corneal topography demonstrated significant improvement in 55%, improvement in 36%, and minor improvement in 9% of cases. No cases progressed as evidenced by keratometry readings.
  
  
  CONCLUSIONS
  Simultaneous TG-PRK with CXL is an effective and safe treatment with remarkable visual and topographic outcomes in patients with low-grade keratoconus who meet the recommended inclusion criteria.
authors.affiliation: Elite Medical Center, Al Riyadh, Kingdom of Saudi Arabia.
authors.forename: Waleed S
authors.initials: WS
authors.lastname: Tuwairqi
authors.forename: Mazen M
authors.initials: MM
authors.lastname: Sinjab
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003131:Combined Modality Therapy; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy / Q000378:metabolism / Q000601:surgery / Q000628:therapy*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D017060:Patient Satisfaction; D018903:Photorefractive Keratectomy; D017319:Photosensitizing Agents / Q000009:adverse effects / Q000627:therapeutic use; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D012256:Riboflavin / Q000009:adverse effects / Q000627:therapeutic use; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin