title: Selective laser trabeculoplasty for early glaucoma: analysis of success predictors and adjusted laser outcomes based on the untreated fellow eye.
abstract: BACKGROUND
  To identify success predictors and to study the role of the fellow untreated eye as a co-variable for adjustment of intraocular pressure (IOP) outcomes following selective laser trabeculoplasty (SLT) in early open-angle glaucoma (OAG) patients.
  
  
  METHODS
  A case series was carried out. Patients with uncontrolled early OAG or ocular hypertension (inadequate IOP control requiring additional treatment) underwent SLT (one single laser session) performed by the same surgeon in a standardized fashion. The same preoperative medical regimen was maintained during follow-up for all patients. Post-treatment assessments were scheduled at week 1 and months 1, 2, and 3. In order to account for possible influence of IOP fluctuation on laser outcomes, post-laser IOP values of the treated eye of each patient were also analyzed adjusting for IOP changes (between visits variation) of the untreated fellow eye (adjusted analysis). Pre and post-laser IOP values were compared using paired t-test. Factors associated with the magnitude of IOP reduction were investigated using multiple regression analysis.
  
  
  RESULTS
  A total of 45 eyes of 45 patients were enrolled. Mean IOP was reduced from 20.8 ± 5.1 to 14.9 ± 2.9 mmHg at month 3 (p < 0.001). Adjusted success rate (defined as IOP reduction ≥ 20%) was 64% and mean percentage of IOP reduction was 23.1 ± 14.3% at last follow-up visit. Considering unadjusted post-laser IOP values, it was found a 20% greater absolute IOP reduction (median [interquartile range] 6 mmHg [4-7] vs 5 mmHg [3-7]; p = 0.04), with a success rate of 76%. Although baseline IOP was significantly associated with both adjusted and unadjusted post-laser IOP reduction, a stronger association was found when unadjusted IOP values were considered (p < 0.001 and R2= 0.35; p < 0.001 and R2= 0.67, respectively). Age, mean deviation (MD) index, central corneal thickness and type of glaucoma were not significant predictors (p ≥ 0.150).
  
  
  CONCLUSIONS
  In this group of patients with early OAG or ocular hypertension, our short-term results confirmed SLT as a safe and effective alternative for IOP reduction. Although better outcomes were found in eyes with higher preoperative IOP, this effect was mitigated when results were adjusted to the fellow untreated eye (to the influence of between visits-IOP fluctuations).
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, Rua Botucatu, 821. Vila Clementino, São Paulo, São Paulo, CEP: 04023-062, Brazil.
authors.forename: Mikael
authors.initials: M
authors.lastname: Chun
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, Rua Botucatu, 821. Vila Clementino, São Paulo, São Paulo, CEP: 04023-062, Brazil. carolepm@gmail.com.
authors.forename: Carolina P B
authors.initials: CP
authors.lastname: Gracitelli
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, Rua Botucatu, 821. Vila Clementino, São Paulo, São Paulo, CEP: 04023-062, Brazil.|Glaucoma Unit, Hospital Medicina dos Olhos, Osasco, São Paulo, Brazil.
authors.forename: Flavio S
authors.initials: FS
authors.lastname: Lopes
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, Rua Botucatu, 821. Vila Clementino, São Paulo, São Paulo, CEP: 04023-062, Brazil.|Glaucoma Unit, Hospital Medicina dos Olhos, Osasco, São Paulo, Brazil.
authors.forename: Luis G
authors.initials: LG
authors.lastname: Biteli
authors.affiliation: Glaucoma Unit, Hospital Medicina dos Olhos, Osasco, São Paulo, Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Ushida
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, Rua Botucatu, 821. Vila Clementino, São Paulo, São Paulo, CEP: 04023-062, Brazil.|Glaucoma Unit, Hospital Medicina dos Olhos, Osasco, São Paulo, Brazil.
authors.forename: Tiago S
authors.initials: TS
authors.lastname: Prata
mesh_terms: D000367:Age Factors; D000368:Aged; D003315:Cornea / Q000503:physiopathology; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012044:Regression Analysis; D014130:Trabeculectomy / Q000379:methods*
keywords: Fellow eye; Intraocular pressure; Open-angle glaucoma; Selective laser trabeculoplasty; Treatment