title: Intraocular Pressure Reduction after Phacoemulsification versus Manual Small-Incision Cataract Surgery: A Randomized Controlled Trial.
abstract: To compare reduction in intraocular pressure (IOP) and change in anterior chamber angle configuration between eyes undergoing phacoemulsification versus those undergoing manual small-incision cataract surgery (MSICS).
  
  
  
  Prospective, randomized, double-masked, parallel assignment clinical trial.
  
  
  
  Five hundred eyes of 500 participants 40 to 70 years of age with normal IOP, gonioscopically open angles, and age-related cataract.
  
  
  
  Eyes underwent phacoemulsification or MSICS after a 1:1 randomization and allocation code. Best-corrected vision, IOP, comprehensive slit-lamp evaluation, and anterior segment (AS) optical coherence tomography (OCT) were performed at baseline and at 1, 3, and 6 months follow-up.
  
  
  
  Change in IOP (ΔIOP) and AS OCT parameters between baseline and 6 months after surgery.
  
  
  
  Six months, similar IOP reduction was observed in eyes undergoing phacoemulsification (ΔIOP = 2.7±2.9 mmHg) and MSICS (ΔIOP = 2.6±2.6 mmHg; P = 0.70). Widening of the angle opening distance (AOD) 500 μm from the scleral spur (median ΔAOD500 = 103 μm; interquartile range = 39-179 μm) was also similar in both groups (P = 0.28). Multivariate linear regression analysis showed that eyes with higher baseline IOP experienced significantly greater reduction in IOP at 6 months (ΔIOP = 0.46-mmHg reduction for every 1-mmHg increment in baseline IOP; 95% confidence interval [CI], 0.4-0.5 mmHg; P < 0.001). After adjusting for covariates, the magnitude of widening of AOD500 was not associated significantly with reduction in IOP (1.33-mmHg reduction for every 1-mm increment in AOD500; P = 0.07). Baseline AOD500 (β = -0.60-mm change/1-mm increment of baseline AOD; 95% CI, -0.67 to -0.53 mm) and anterior chamber depth (β = 0.07-mm change/1-mm increment of baseline anterior chamber depth; 95% CI, 0.04-0.1 mm) were significant predictors of AOD500 widening at 6 months.
  
  
  
  Both phacoemulsification and MSICS led to significant and similar IOP reductions 6 months after surgery, and both surgeries produced similar changes in anterior chamber and angle parameters. Higher baseline IOP was associated with greater IOP reduction; IOP reduction also can be attributed partly to changes in angle and anterior chamber configuration, although these parameters were unable to predict significantly predict IOP drop at 6 months.
authors.affiliation: Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Pondicherry, India.
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Sengupta
authors.affiliation: Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Pondicherry, India. Electronic address: venkatesh@pondy.aravind.org.
authors.forename: Rengaraj
authors.initials: R
authors.lastname: Venkatesh
authors.affiliation: Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Pondicherry, India.
authors.forename: Palaniswamy
authors.initials: P
authors.lastname: Krishnamurthy
authors.affiliation: Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Pondicherry, India.
authors.forename: Manas
authors.initials: M
authors.lastname: Nath
authors.affiliation: Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Pondicherry, India.
authors.forename: Abha
authors.initials: A
authors.lastname: Mashruwala
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Pradeep Y
authors.initials: PY
authors.lastname: Ramulu
authors.affiliation: Department of Ophthalmology, University of Maryland, Baltimore, Maryland; Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Robin
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
authors.forename: Paul
authors.initials: P
authors.lastname: Lee
mesh_terms: D000869:Anterior Eye Segment / Q000000981:diagnostic imaging; D002387:Cataract Extraction; D004311:Double-Blind Method; D005260:Female; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D018918:Phacoemulsification; D011184:Postoperative Period; D011446:Prospective Studies; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology