title: Comparison of postoperative pain in patients following photorefractive keratectomy versus advanced surface ablation.
abstract: OBJECTIVE
  To compare postoperative pain associated with advanced surface ablation versus traditional photorefractive keratectomy (PRK).
  
  
  METHODS
  Codet-Aris Vision Institute, Tijuana, Mexico.
  
  
  METHODS
  This prospective double-masked randomized study included 56 eyes of 28 myopic patients who received traditional PRK in 1 eye and advanced surface ablation in the contralateral eye. For advanced surface ablation, removal of corneal epithelium was performed by incubating the cornea with 18% ethanol. Subsequently, the epithelium was removed by a surgical microsponge. For eyes treated by PRK, mechanical debridement of corneal epithelium was performed with a surgical blade. Excimer laser corneal ablation was performed using the Nidek EC-5000 excimer laser in all eyes. On postoperative days 1 and 3, patients were instructed to rate their pain via 3 pain measuring tools: (1) a global subjective rating; (2) a 100 mm visual analog scale (VAS); and (3) an 11-point numerical rating scale.
  
  
  RESULTS
  All 28 patients completed postoperative questionnaires on day 1 and day 3. On postoperative day 1, all reported pain in both eyes. Using the global assessment rating, patients reported statistically significant more pain in eyes treated by advanced surface ablation (P = .0037; confidence interval [CI], 59%-92%). Furthermore, based on the 11-point numerical rating scale, mean pain scores were significantly higher in the advanced surface ablation treated eyes (P = .0121), while the VAS mean pain scores were marginally significantly higher (P = .0822). On postoperative day 3, 23 patients reported the presence of some pain, at least in 1 eye. Using the global assessment rating, 70% of the those who had pain reported more pain in the advanced surface ablation-treated eye (advanced surface ablation 16/23 versus PRK 7/23) (P = .0931; 95% CI, 47%-87%). In addition, on postoperative day 3, advanced surface ablation-treated eyes demonstrated slightly higher mean pain scores based on the 11-point numerical rating scale and on the VAS; however, mean differences were not statistically significant (P = .3494 and P = .3337, respectively).
  
  
  CONCLUSIONS
  Advanced surface ablation was associated with statistically significantly more postoperative pain than PRK on postoperative day 1. A greater percentage of patients reported more pain in the advanced surface ablation-treated eyes on day 3. Refractive surgeons should consider the postoperative pain associated with advanced surface ablation when deciding on the type of epithelial debridement for their patients.
authors.affiliation: University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Charles Richard
authors.initials: CR
authors.lastname: Blake
authors.forename: Rene A
authors.initials: RA
authors.lastname: Cervantes-Castañeda
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Macias-Rodríguez
authors.forename: George
authors.initials: G
authors.lastname: Anzoulatous
authors.forename: Robert
authors.initials: R
authors.lastname: Anderson
authors.forename: Arturo S
authors.initials: AS
authors.lastname: Chayet
mesh_terms: D003646:Debridement / Q000379:methods*; D004311:Double-Blind Method; D019573:Epithelium, Corneal / Q000187:drug effects / Q000601:surgery; D000431:Ethanol / Q000494:pharmacology; D006801:Humans; D054018:Lasers, Excimer; D009216:Myopia / Q000601:surgery*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000209:etiology*; D018903:Photorefractive Keratectomy / Q000379:methods*; D011446:Prospective Studies; D011795:Surveys and Questionnaires
chemical_list: D000431:Ethanol