title: Glaucoma anterior chamber morphometry based on optical Scheimpflug images.
abstract: OBJECTIVE
  To compare the performance of gonioscopy and noncontact morphometry with anterior chamber tomography (High Resolution Pentacam - HR) using optical Scheimpflug images in the evaluation of the anterior chamber angle (ACA).
  
  
  METHODS
  Transversal study. 112 eyes from 74 subjects evaluated at the Glaucoma Department, Fluminense Federal University, underwent gonioscopy and Pentacam HR. Using gonioscopy, the ACA was graded using the Shaffer Classification (SC) by a single experienced examiner masked to the Pentacam HR findings. Narrow angle was determined in eyes in which the posterior trabecular meshwork could not be seen in two or more quadrants on non-indentation gonioscopy (SC Grade 2 or less). Pentacam HR images of the nasal and temporal quadrants were evaluated by custom software to automatically obtain anterior chamber measurements, such as: anterior chamber angle (ACA), anterior chamber volume (ACV) and anterior chamber depth (ACD).
  
  
  RESULTS
  Based on gonioscopy results, 74 (60.07%) eyes of patients classified as open-angle (SC 3 and 4) and 38 (33.93%) eyes of patients classified as narrow-angle (SC 1 and 2). Noncontact morphometry with Scheimpflug images revealed a mean ACA of 39.20 ± 5.31 degrees for open-angle and 21.18 ± 7.98 degrees for narrow-angle. The open-angle group showed significant greater ACV and ACD values when compared to narrow-angle group (ACV of 193 ± 36 mm³ vs. 90 ± 25 mm³, respectively, p<0.001; and ACD of 3,09 ± 0,42 mm vs. 1,55 ± 0,64 mm, respectively, p<0.0001.). In screening eyes with open-angle and narrow-angle with the Pentacam ACA of 20º (SC Grade 2) using the ROC curves, the analysis showed 52.6% of sensitivity and 100% of specificity.
  
  
  CONCLUSIONS
  The Pentacam showed ability in detecting eyes at risk for angle closure analyzing ACV and ACD.
authors.affiliation: Department of Ophthalmology, Universidade Federal Fluminense, Rio de Janeiro, RJ, Brazil. ruizsa@hotmail.com
authors.forename: Ruiz Simonato
authors.initials: RS
authors.lastname: Alonso
authors.forename: Renato
authors.initials: R
authors.lastname: Ambrósio Junior
authors.forename: Augusto
authors.initials: A
authors.lastname: Paranhos Junior
authors.forename: Lisandro Massanori
authors.initials: LM
authors.lastname: Sakata
authors.forename: Marcelo Palis
authors.initials: MP
authors.lastname: Ventura
mesh_terms: D000328:Adult; D000368:Aged; D000867:Anterior Chamber / Q000000981:diagnostic imaging / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000000981:diagnostic imaging / Q000473:pathology*; D006068:Gonioscopy / Q000145:classification / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D014463:Ultrasonography; D055815:Young Adult