title: One-Year Clinical Outcomes of a Two-Step Surgical Management for Keratoconus-Topography-Guided Photorefractive Keratectomy/Cross-Linking After Intrastromal Corneal Ring Implantation.
abstract: OBJECTIVE
  To present the results of same-day topography-guided photorefractive keratectomy (TG-PRK) and corneal collagen cross-linking (CXL) after intrastromal corneal ring (ISCR) implantation in patients with keratoconus.
  
  
  METHODS
  Thirty-three patients (41 eyes) aged between 19 and 45 years were included in this prospective study. All patients underwent a femtosecond laser-enabled (Intralase FS; Abbott Medical Optics, Inc.) placement of intracorneal ring segments (Kerarings; Mediphacos, Brazil). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and keratometry readings remained stable for 6 months. Same-day PRK and CXL was subsequently performed in all patients.
  
  
  RESULTS
  After 12 months of completion of the procedure, mean UDVA in log of minimal angle of resolution was significantly improved (0.74±0.54-0.10±0.16); CDVA did not improve significantly but 85% of eyes maintained or gained multiple lines of CDVA; mean refraction spherical equivalent improved (from -3.03±1.98 to -0.04±0.99 D), all keratometry readings were significantly reduced, from preoperative values, but coma did not vary significantly from preoperative values. Central corneal thickness and corneal thickness at the thinnest point were significantly (P<0.0001) reduced from 519.76±29.33 and 501.87±31.50 preoperatively to 464.71±36.79 and 436.55±47.42 postoperatively, respectively. Safety and efficacy indices were 0.97 and 0.88, respectively. From 6 months up until more than 1 year of follow-up, further significant improvement was observed only for UDVA (P<0.0001).
  
  
  CONCLUSIONS
  Same-day combined TG-PRK and CXL after ISCR implantation is a safe and effective option for improving visual acuity and visual function, and it halts the progression of the keratoconus. The improvements recorded after 6 months of follow-up were maintained or improved upon 1 year after the procedure.
authors.affiliation: Department of Ophthalmology (W.S.A.-T., H.R.), Elite Medical and Surgical Center, Riyadh, Saudi Arabia; School of Optometry & Vision Science, Institute of Health & Biomedical Innovation (U.L.O.), Visual and Ophthalmic Optics Group (Chronic Disease & Ageing Domain), Queensland University of Technology, Brisbane, Queensland, Australia; and Department of Medicine (K.C.O.), Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: Waleed S
authors.initials: WS
authors.lastname: Al-Tuwairqi
authors.forename: Uchechukwu L
authors.initials: UL
authors.lastname: Osuagwu
authors.forename: Haya
authors.initials: H
authors.lastname: Razzouk
authors.forename: Kelechi C
authors.initials: KC
authors.lastname: Ogbuehi
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism; D003131:Combined Modality Therapy; D003319:Corneal Stroma / Q000378:metabolism / Q000601:surgery*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy / Q000378:metabolism / Q000601:surgery*; D054018:Lasers, Excimer / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D018903:Photorefractive Keratectomy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011446:Prospective Studies; D019919:Prosthesis Implantation; D012029:Refraction, Ocular; D012256:Riboflavin / Q000627:therapeutic use*; D013997:Time Factors; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin