title: Compass: clinical evaluation of a new instrument for the diagnosis of glaucoma.
abstract: OBJECTIVE
  To evaluate Compass, a new instrument for glaucoma screening and diagnosis that combines scanning ophthalmoscopy, automated perimetry, and eye tracking.
  
  
  METHODS
  A total of 320 human subjects (200 normal, 120 with glaucoma) underwent full ophthalmological evaluation and perimetric evaluation using the Humphrey SITA standard 24° test (HFA), and the Compass test that consisted of a full-threshold program on the central 24° with a photograph of the central 30° of the retina. A subgroup of normal subjects and glaucoma patients underwent a second Compass test during the same day in order to study test-retest variability. After exclusion of 30 patients due to protocol rules, a database was created to compare the Compass to the HFA, and to evaluate retinal image quality and fixation stability.
  
  
  RESULTS
  The difference in mean sensitivity between Compass and HFA was -1.02 ± 1.55 dB in normal subjects (p<0.001) and -1.01 ± 2.81 dB in glaucoma (p<0.001). Repeatability SD for the average sensitivity was 1.53 for normal subjects and 1.84 for glaucoma. Test time with the Compass was 634±96 s (607±78 for normals, 678±108 for glaucoma). Compass analysis showed the percentage of fixation within the central 1° was 86.6% in normal subjects, and 79.3% in glaucoma patients. Color image quality was sufficient for diagnostic use in >65% of cases; Image-based diagnosis was in accordance with the initial diagnosis in 85% of the subjects.
  
  
  CONCLUSIONS
  Based on preliminary results, Compass showed useful diagnostic characteristics for the study of glaucoma, and combined morphological information with functional data.
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy.
authors: Luca
authors: L
authors: Rossetti
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy.
authors: Maurizio
authors: M
authors: Digiuni
authors: CenterVue, Padova, Italy.
authors: Alberto
authors: A
authors: Rosso
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy.
authors: Roberta
authors: R
authors: Riva
authors: CenterVue, Padova, Italy.
authors: Giuliano
authors: G
authors: Barbaro
authors: CLEVER Eye Institute, Slidell, Louisiana, United States of America.
authors: Michael K
authors: MK
authors: Smolek
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy.
authors: Nicola
authors: N
authors: Orzalesi
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy; Unit of Ophthalmology, Ospedale Maggiore della Carità, Novara, Italy.
authors: Stefano
authors: S
authors: De Cilla'
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy.
authors: Alessandro
authors: A
authors: Autelitano
authors: Eye Clinic, Department of Medicine, Surgery and Odontoiatry, Ospedale San Paolo, University of Milan, Milan Italy.
authors: Paolo
authors: P
authors: Fogagnolo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001331:Automation; D016208:Databases, Factual; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods*; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields