title: Intraocular straylight before and after low myopic photorefractive keratectomy with and without mitomycin C.
abstract: OBJECTIVE
  To evaluate ocular straylight before and after photorefractive keratectomy (PRK) for low myopia with and without topical mitomycin (MMC) treatment.
  
  
  METHODS
  Patients who underwent PRK for low myopia were enrolled into the study. PRK without MMC was performed in 21 eyes (12 patients), whereas PRK with topical 0.02% MMC was performed in 25 eyes (14 patients). Both groups were treated using the NIDEK EC5000 excimer laser. Measurements were performed using the C-Quant straylight meter preoperatively and at two and four months postoperatively.
  
  
  RESULTS
  The mean patient age was 30 ± 4 years, and the mean spherical equivalent refractive error was -2.2 ± 0.75 D. The mean preoperative intraocular straylight values were 1.07 ± 0.10 in the PRK without MMC group and 1.07 ± 0.11 log(s) in the PRK with topical MMC group. At two months after surgery, there was a decrease in mean intraocular straylight values in both groups. However, a significant difference was only reached in the PRK with MMC group [0.98 ± 0.09 log(s), p=0.002] compared with preoperative values, which was likely due to a greater scatter of measurements in the PRK without MMC group [1.03 ± 0.13 log(s), p=0.082]. At four months postoperatively, ocular straylight values were not significantly different compared with those at baseline in either the PRK without MMC group [1.02 ± 0.14 log(s), p=0.26] or in the PRK with topical MMC group [1.02 ± 0.11 log(s), p=0.13].
  
  
  CONCLUSIONS
  PRK for low myopia decreases ocular straylight, and MMC application further reduces straylight in the early postoperative period. However, ocular straylight values do not significantly differ at four months after surgery compared with those at baseline.
authors.affiliation: Department of Ophthalmology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Andre Augusto Miranda
authors.initials: AA
authors.lastname: Torricelli
authors.affiliation: Department of Ophthalmology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Taís Renata Ribeiro
authors.initials: TR
authors.lastname: Parede
authors.affiliation: Department of Ophthalmology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Marcelo Vieira
authors.initials: MV
authors.lastname: Netto
authors.affiliation: Department of Ophthalmology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Francisco Penteado
authors.initials: FP
authors.lastname: Crestana
authors.affiliation: Department of Ophthalmology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Samir Jacob
authors.initials: SJ
authors.lastname: Bechara
mesh_terms: D060433:Administration, Ophthalmic; D000328:Adult; D003316:Corneal Diseases / Q000517:prevention & control; D057108:Corneal Wavefront Aberration / Q000503:physiopathology*; D003432:Cross-Linking Reagents / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008027:Light; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage*; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D011184:Postoperative Period; D012542:Scattering, Radiation
chemical_list: D003432:Cross-Linking Reagents; D016685:Mitomycin