title: Reliability of a Manual Procedure for Marking the EZ Endpoint Location in Patients with Retinitis Pigmentosa.
abstract: OBJECTIVE
  We developed and evaluated a training procedure for marking the endpoints of the ellipsoid zone (EZ), also known as the inner segment/outer segment (IS/OS) border, on frequency domain optical coherence tomography (fdOCT) scans from patients with retinitis pigmentosa (RP).
  
  
  METHODS
  A manual for marking EZ endpoints was developed and used to train 2 inexperienced graders. After training, an experienced grader and the 2 trained graders marked the endpoints on fdOCT horizontal line scans through the macula from 45 patients with RP. They marked the endpoints on these same scans again 1 month later.
  
  
  RESULTS
  Intragrader agreement was excellent. The intraclass correlation coefficient (ICC) was 0.99, the average difference of endpoint locations (19.6 μm) was close to 0 μm, and the 95% limits were between -284 and 323 μm, approximately ±1.1°. Intergrader agreement also was excellent. The ICC values were 0.98 (time 1) and 0.97 (time 2), the average difference among graders was close to zero, and the 95% limits of these differences was less than 350 μm, approximately 1.2°, for both test times.
  
  
  CONCLUSIONS
  While automated algorithms are becoming increasingly accurate, EZ endpoints still have to be verified manually and corrected when necessary. With training, the inter- and intragrader agreement of manually marked endpoints is excellent.
  
  
  CONCLUSIONS
  For clinical studies, the EZ endpoints can be marked by hand if a training procedure, including a manual, is used. The endpoint confidence intervals, well under ±2.0°, are considerably smaller than the 6° spacing for the typically used static visual field.
authors.affiliation: Department of Psychology, Columbia University, New York, NY, USA.
authors.forename: Rithambara
authors.initials: R
authors.lastname: Ramachandran
authors.affiliation: Department of Psychology, Columbia University, New York, NY, USA.
authors.forename: Cindy
authors.initials: C
authors.lastname: X Cai
authors.affiliation: Department of Psychology, Columbia University, New York, NY, USA.
authors.forename: Dongwon
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Psychology, Columbia University, New York, NY, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: C Epstein
authors.affiliation: Retina Foundation of Southwest, Dallas,TX, USA.
authors.forename: Kirsten G
authors.initials: KG
authors.lastname: Locke
authors.affiliation: Retina Foundation of Southwest, Dallas,TX, USA ; Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: David
authors.initials: D
authors.lastname: G Birch
authors.affiliation: Department of Psychology, Columbia University, New York, NY, USA ; Department of Ophthalmology, Columbia University, New York, NY, USA.
authors.forename: Donald
authors.initials: D
authors.lastname: C Hood
keywords: ellipsoid zone (EZ); optical coherence tomography; receptors; retinitis pigmentosa