title: Reduction in intraocular pressure after cataract extraction: the Ocular Hypertension Treatment Study.
abstract: OBJECTIVE
  To determine the change in intraocular pressure (IOP) after cataract extraction in the observation group of the Ocular Hypertension Treatment Study.
  
  
  METHODS
  Comparative case series.
  
  
  METHODS
  Forty-two participants (63 eyes) who underwent cataract surgery in at least 1 eye during the study and a control group of 743 participants (743 eyes) who did not undergo cataract surgery.
  
  
  METHODS
  We defined the "split date" as the study visit date at which cataract surgery was reported in the cataract surgery group and a corresponding date in the control group. Preoperative IOP was defined as the mean IOP of up to 3 visits before the split date. Postoperative IOP was the mean IOP of up to 3 visits including the split date (0, 6, and 12 months' with "0 months" equaling the split date). In both groups, we censored data after initiation of ocular hypotensive medication or glaucoma surgery of any kind.
  
  
  METHODS
  Difference in preoperative and postoperative IOP.
  
  
  RESULTS
  In the cataract group, postoperative IOP was significantly lower than the preoperative IOP (19.8 ± 3.2 mmHg vs. 23.9 ± 3.2 mmHg; P<0.001). The postoperative IOP remained lower than the preoperative IOP for at least 36 months. The average decrease in postoperative IOP from preoperative IOP was 16.5%, and 39.7% of eyes had postoperative IOP ≥ 20% below preoperative IOP. A greater reduction in postoperative IOP occurred in the eyes with the highest preoperative IOP. In the control group, the corresponding mean IOPs were 23.8 ± 3.6 before the split date and 23.4 ± 3.9 after the split date.
  
  
  CONCLUSIONS
  Cataract surgery decreases IOP in patients with ocular hypertension over a long period of time.
authors.affiliation: Devers Eye Institute/Discoveries in Sight, Legacy Health System, Portland, Oregon, USA. smansberger@deverseye.org
authors.forename: Steven L
authors.initials: SL
authors.lastname: Mansberger
authors.forename: Mae O
authors.initials: MO
authors.lastname: Gordon
authors.forename: Henry
authors.initials: H
authors.lastname: Jampel
authors.forename: Anjali
authors.initials: A
authors.lastname: Bhorade
authors.forename: James D
authors.initials: JD
authors.lastname: Brandt
authors.forename: Brad
authors.initials: B
authors.lastname: Wilson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kass
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011184:Postoperative Period; D013997:Time Factors; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology
chemical_list: D000959:Antihypertensive Agents