title: Scleral intraocular pressure measurement in cadaver eyes pre- and postkeratoprosthesis implantation.
abstract: OBJECTIVE
  We correlated scleral IOP to assigned IOP using pneumatonometry in cadaver eyes before and after Boston type I keratoprosthesis (KPro) implantation.
  
  
  METHODS
  Corneal IOP and scleral IOP at the superonasal, superotemporal, inferotemporal, and inferonasal quadrants were measured using pneumatonometry in six cadaver eyes cannulated with an infusion line with assigned IOP held at 20, 30, 40, and 50 mm Hg. Measurements of scleral IOP at the same location were repeated after a KPro was implanted. Correlations between scleral IOP and assigned IOP were analyzed for the entire group of eyes, and for each individual eye before and after KPro. One eye was tested by another masked grader for interobserver variability.
  
  
  RESULTS
  Scleral IOP measured higher than corneal IOP by a mean of 13.2 mm Hg. For group analysis, pre-KPro scleral IOP had a positive and linear correlation with assigned IOP in all quadrants (P < 0.00001), and this correlation was preserved after KPro implantation (P < 0.00001). There was strong interobserver agreement in all measurement sites (P < 0.001). In analyses of individual eyes, scleral IOP measured at the inferotemporal quadrant confirmed the strong linear association between scleral IOP and assigned IOP before and after KPro for all study eyes. A Bland-Altman plot showed that the difference in scleral IOP between pre-KPro and post-KPro eyes fell mostly within ± 5 mm Hg.
  
  
  CONCLUSIONS
  Scleral IOP measured by pneumatonometry may be used to estimate IOP in cadaver eyes with and without keratoprosthesis. This may be a potential modality for assessing IOP for patients with corneal pathology or keratoprosthesis.
authors.affiliation: Department of Ophthalmology, Stanford University, Stanford, California, United States.
authors.forename: Charles C
authors.initials: CC
authors.lastname: Lin
authors.forename: Aiyin
authors.initials: A
authors.lastname: Chen
authors.forename: Bennie H
authors.initials: BH
authors.lastname: Jeng
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Ou
authors.forename: Ying
authors.initials: Y
authors.lastname: Han
mesh_terms: D002102:Cadaver; D003316:Corneal Diseases / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D011184:Postoperative Period; D057234:Preoperative Period; D019736:Prostheses and Implants; D012372:ROC Curve; D012590:Sclera; D014065:Tonometry, Ocular / Q000379:methods*
keywords: glaucoma anterior segment; intraocular pressure; keratoprosthesis; scleral pressure