title: Glaucoma Surgery Calculator: Limited Additive Effect of Phacoemulsification on Intraocular Pressure in Ab Interno Trabeculectomy.
abstract: OBJECTIVE
  To compare intraocular pressure (IOP) reduction and to develop a predictive surgery calculator based on the results between trabectome-mediated ab interno trabeculectomy in pseudophakic patients versus phacoemulsification combined with trabectome-mediated ab interno trabeculectomy in phakic patients.
  
  
  METHODS
  This observational surgical cohort study analyzed pseudophakic patients who received trabectome-mediated ab interno trabeculectomy (AIT) or phacoemulsification combined with AIT (phaco-AIT). Follow up for less than 12 months or neovascular glaucoma led to exclusion. Missing data was imputed by generating 5 similar but non-identical datasets. Groups were matched using Coarsened Exact Matching based on age, gender, type of glaucoma, race, preoperative number of glaucoma medications and baseline intraocular pressure (IOP). Linear regression was used to examine the outcome measures consisting of IOP and medications.
  
  
  RESULTS
  Of 949 cases, 587 were included consisting of 235 AIT and 352 phaco-AIT. Baseline IOP between groups was statistically significant (p≤0.01) in linear regression models and was minimized after Coarsened Exact Matching. An increment of 1 mmHg in baseline IOP was associated with a 0.73±0.03 mmHg IOP reduction. Phaco-AIT had an IOP reduction that was only 0.73±0.32 mmHg greater than that of AIT. The resulting calculator to determine IOP reduction consisted of the formula -13.54+0.73 × (phacoemulsification yes:1, no:0) + 0.73 × (baseline IOP) + 0.59 × (secondary open angle glaucoma yes:1, no:0) + 0.03 × (age) + 0.09 × (medications).
  
  
  CONCLUSIONS
  This predictive calculator for minimally invasive glaucoma surgery can assist clinical decision making. Only a small additional IOP reduction was observed when phacoemulsification was added to AIT. Patients with a higher baseline IOP had a greater IOP reduction.
authors.affiliation: Rosalind Franklin University of Medicine and Science, Chicago Medical School, Chicago, United States of America.
authors.forename: Ashley E
authors.initials: AE
authors.lastname: Neiweem
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America.
authors.forename: Igor I
authors.initials: II
authors.lastname: Bussel
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America.
authors.forename: Joel S
authors.initials: JS
authors.lastname: Schuman
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America.|Department of Ophthalmology, School of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Brown
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, United States of America.
authors.forename: Nils A
authors.identifier: http://orcid.org/0000-0001-7167-1213
authors.initials: NA
authors.lastname: Loewen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015331:Cohort Studies; D005260:Female; D005901:Glaucoma / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure; D007908:Lens, Crystalline / Q000503:physiopathology / Q000601:surgery; D016014:Linear Models; D008297:Male; D055641:Mathematical Concepts; D008875:Middle Aged; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care / Q000379:methods; D018918:Phacoemulsification / Q000379:methods*; D019591:Pseudophakia / Q000503:physiopathology / Q000601:surgery; D014129:Trabecular Meshwork / Q000503:physiopathology / Q000601:surgery; D014130:Trabeculectomy / Q000379:methods*; D058609:Visual Field Tests