Preoperative iris configuration and intraocular pressure after cataract surgery

J Cataract Refract Surg. 2012 Jan;38(1):117-23. doi: 10.1016/j.jcrs.2011.07.033. Epub 2011 Nov 13.


Purpose: To determine predictors of long-term intraocular pressure (IOP) after cataract surgery.

Setting: Hunter Holmes McGuire Veterans Administration Hospital, Richmond, Virginia, USA.

Design: Case series.

Methods: Clinical variables, IOP by applanation tonometry, anatomic features on anterior segment optical coherence tomography (AS-OCT), and gonioscopy were assessed before and after uneventful cataract surgery in eyes with open filtration angles. Multivariate linear regression of preoperative measurements was used to predict the mean IOP from 2 to 18 months postoperatively.

Results: The study enrolled 77 eyes (77 patients). Prediction of the mean postoperative IOP improved when up to 4 preoperative IOP values were averaged (r(2) = 0.20) compared with using the final preoperative IOP value only (r(2) = 0.13). The mean iris cross-sectional area decreased after surgery, from 3.84 mm(2) to 3.70 mm(2) (P=.01). The mean convex hull of the iris segments also decreased, from 5.05 mm(2) to 4.19 mm(2) (P<.001). The mean postoperative IOP was independently predicted by the preoperative average IOP, primary open-angle glaucoma, and the convex hull of cross-sectional iris segments (P=.001, model r(2) = 0.38) or iris cross-sectional area (P=.003, model r(2) = 0.36). Phacoemulsification parameters, incision type, and anterior chamber angle and depth did not predict postoperative IOP.

Conclusions: Averaging up to 4 preoperative IOP values improved postoperative IOP predictions. A high iris cross-sectional area or convex hull of the iris segments on AS-OCT was associated with lower postoperative IOP. These findings might help identify patients who are likely to have the largest IOP drop after cataract surgery.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Anatomy, Cross-Sectional
  • Anterior Eye Segment / pathology
  • Antihypertensive Agents / administration & dosage
  • Female
  • Glaucoma, Open-Angle / drug therapy
  • Glaucoma, Open-Angle / physiopathology
  • Gonioscopy
  • Humans
  • Intraocular Pressure / physiology*
  • Iris / anatomy & histology*
  • Lens Implantation, Intraocular*
  • Male
  • Phacoemulsification*
  • Postoperative Period
  • Preoperative Period
  • Prospective Studies
  • Refraction, Ocular / physiology
  • Tomography, Optical Coherence
  • Tonometry, Ocular
  • Visual Acuity / physiology


  • Antihypertensive Agents