title: Distinguishing wet from dry age-related macular degeneration using three-dimensional computer-automated threshold Amsler grid testing.
abstract: OBJECTIVE
  With the increased efficacy of current therapy for wet age-related macular degeneration (AMD), better ways to detect wet AMD are needed. This study was designed to test the ability of three-dimensional contrast threshold Amsler grid (3D-CTAG) testing to distinguish wet AMD from dry AMD.
  
  
  METHODS
  Conventional paper Amsler grid and 3D-CTAG tests were performed in 90 eyes: 63 with AMD (34 dry, 29 wet) and 27 controls. Qualitative comparisons were based upon the three-dimensional shapes of central visual field (VF) defects. Quantitative analyses considered the number and volume of the three-dimensional defects.
  
  
  RESULTS
  25/34 (74%) dry AMD and 6/29 (21%) wet AMD eyes had no distortions on paper Amsler grid. Of these, 5/25 (20%) dry and 6/6 (100%) wet (p=0.03) AMD eyes exhibited central VF defects with 3D-CTAG. Wet AMD displayed stepped defects in 16/28 (57%) eyes, compared with only 2/34 (6%) of dry AMD eyes (p=0.002). All three volumetric indices of VF defects were two- to four-fold greater in wet than dry AMD (p<0.006). 3D-CTAG had 83.9% positive and 90.6% negative predictive values for wet AMD.
  
  
  CONCLUSIONS
  3D-CTAG has a higher likelihood of detecting central VF defects than conventional Amsler grid, especially in wet AMD. Wet AMD can be distinguished from dry AMD by qualitative and quantitative 3D-CTAG criteria. Thus, 3D-CTAG may be useful in screening for wet AMD, quantitating disease severity, and providing a quantitative outcome measure of therapy.
authors.affiliation: VMR Institute, Huntington Beach, CA 92647, USA.
authors.forename: Craig D
authors.initials: CD
authors.lastname: Robison
authors.forename: Renu V
authors.initials: RV
authors.lastname: Jivrajka
authors.forename: Simon R
authors.initials: SR
authors.lastname: Bababeygy
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fink
authors.forename: Alfredo A
authors.initials: AA
authors.lastname: Sadun
authors.forename: J
authors.initials: J
authors.lastname: Sebag
mesh_terms: D000368:Aged; D015350:Contrast Sensitivity; D003430:Cross-Sectional Studies; D003936:Diagnosis, Computer-Assisted; D005189:False Positive Reactions; D005260:Female; D005451:Fluorescein Angiography; D057092:Geographic Atrophy / Q000175:diagnosis*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis*; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields; D057135:Wet Macular Degeneration / Q000175:diagnosis*