title: Determinants of postoperative corneal edema and impact on goldmann intraocular pressure.
abstract: OBJECTIVE
  Recent studies report that increased corneal edema because of contact lens wear under closed lids is associated with elevated Goldmann intraocular pressure (GAT IOP). We sought to assess whether the impact of postoperative corneal edema on GAT IOP would be similar and to determine the differential effect of different amounts of edema.
  
  
  METHODS
  The setting is a tertiary level cataract clinic in Shantou, China. Pre- and postoperative (day 1) GAT IOP, central corneal thickness (CCT), corneal hysteresis, corneal resistance factor, and radius of corneal curvature were measured for consecutive patients undergoing phacoemulsification surgery by 2 experienced surgeons. Corneal edema was calculated as the percentage increase in CCT.
  
  
  RESULTS
  Among 136 subjects (mean age, 62.5 ± 15.4 years; 53.7% women), the mean increase in CCT was 10.3% postoperatively. Greater corneal edema was associated with lower GAT IOP in unadjusted analyses (P < 0.03) and in linear regression models (P < 0.01). In the model, higher corneal resistance factor (P < 0.001), lower corneal hysteresis (P < 0.001), and steeper radius of corneal curvature (P < 0.001) were associated with higher GAT IOP. Among subjects with edema < the median, edema was associated with lower GAT IOP (P = 0.004), whereas among those with edema ≥ the median, edema was not associated with GAT IOP. An increase in CCT of 7% was associated with an 8 mm Hg underestimation of GAT IOP in our models.
  
  
  CONCLUSIONS
  The effect of postoperative edema on GAT IOP seems to be the opposite of contact lens-induced edema. The magnitude of the effect is potentially relevant to patient management.
authors.affiliation: Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, China.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Huang
authors.forename: Mingzhi
authors.initials: M
authors.lastname: Zhang
authors.forename: Chukai
authors.initials: C
authors.lastname: Huang
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Dennis S C
authors.initials: DS
authors.lastname: Lam
authors.forename: Shaobin
authors.initials: S
authors.lastname: Zhang
authors.forename: Nathan
authors.initials: N
authors.lastname: Congdon
mesh_terms: D003315:Cornea / Q000503:physiopathology; D015715:Corneal Edema / Q000209:etiology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011183:Postoperative Complications; D014065:Tonometry, Ocular