title: Combined use of frequency doubling perimetry and polarimetric measurements of retinal nerve fiber layer in glaucoma detection.
abstract: OBJECTIVE
  The aim of this study was to evaluate the diagnostic usefulness of the combined use of frequency-doubling technology (FDT) perimetry and polarimetry of the retinal nerve fiber layer.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Seventy ocular hypertensive patients (normal optic disk and standard perimetry, elevated intraocular pressure [>21 mm Hg]), 59 patients with "preperimetric" open-angle glaucoma (glaucomatous optic disk atrophy, elevated intraocular pressure [>21 mm Hg], no visual field defect in standard perimetry), 105 patients with "perimetric" open-angle glaucoma (glaucomatous optic disk atrophy and clearly marked visual field defect), and 73 control subjects had FDT screening (protocol: C-20-5) and polarimetric measurements (GDx). Criteria for exclusion: optic disks larger than 4 mm(2), media opacities, patients younger than 33 years or older than 66 years. None of the subjects had earlier FDT perimetry. One eye of each patient and control subject entered the statistical evaluation. Database and statistical software were used for case-wise recalculation of all missed localized probability levels to create a FDT screening score.
  
  
  RESULTS
  At a predefined specificity of 94.5% in control eyes, discrimination between "perimetric" glaucoma and normal subjects is superior using the FDT perimetry (sensitivity = 84.8%) in comparison to polarimetry (sensitivity = 63.8%), whereas sensitivity is similar with both methods in "preperimetric" patients (GDx, FDT: 25.4%). In several cases, patients classified as glaucomatous by the GDx are not the same patients as identified by the FDT perimetry. Therefore, a two-dimensional discrimination analysis can increase correct positive classification. Using a linear combination of the present FDT screening score and polarimetry ("the number"), 92.4% of "perimetric" glaucoma eyes and 44.1% of "preperimetric" glaucoma eyes have been classified as glaucomatous.
  
  
  CONCLUSIONS
  Joint usage of polarimetry and FDT perimetry indicate that a combination of different techniques which can uncover different glaucoma properties, might be helpful in early glaucoma detection.
authors.affiliation: Department of Ophthalmology and University Eye Hospital, Friedrich-Alexander University Erlangen-Nürnberg at Erlangen, Erlangen, Germany. folkert.horn@augen.imed.uni-erlangen.de
authors.forename: Folkert K
authors.initials: FK
authors.lastname: Horn
authors.forename: Nhung X
authors.initials: NX
authors.lastname: Nguyen
authors.forename: Christian Y
authors.initials: CY
authors.lastname: Mardin
authors.forename: Anselm G
authors.initials: AG
authors.lastname: Jünemann
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009798:Ocular Hypertension / Q000175:diagnosis; D009900:Optic Nerve / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields