title: Polarimetric measurement of retinal nerve fiber layer thickness in glaucoma diagnosis.
abstract: OBJECTIVE
  To evaluate reliability and diagnostic value of polarimetric measurements of the retinal nerve fiber layer (RNFL) thickness in the diagnosis of glaucoma.
  
  
  METHODS
  The study included 81 eyes with perimetric glaucoma with glaucomatous changes of the optic disc and visual field defects; 52 eyes with preperimetric glaucoma with glaucomatous optic disc abnormalities and normal achromatic visual fields; and 70 normal eyes. For determination of reliability, four examiners repeated polarimetric measurements five times in ten normal subjects.
  
  
  RESULTS
  The polarimetric variables were significantly correlated with increasing mean visual field defect and decreasing neuroretinal rim area. In correlation analyses with visual field defects, correlation coefficients were highest for the variable "superior/nasal ratio" and "the Number," a variable calculated by the neural network of the device. In correlations with neuroretinal rim area, correlation coefficients were highest for measurements of the inferior nerve fiber layer thickness. The preperimetric glaucoma group and the control group differed significantly in the variables "superior/nasal ratio" and "the Number" and, to a smaller degree, in the variables "superior/temporal ratio" and "superior/inferior ratio." The Number variable had a sensitivity of 82% and 58% at a predefined specificity of 80% in separating perimetric glaucoma patients and preperimetric glaucoma patients, respectively, from control subjects. Reproducibility of the polarimetric measurements ranged between 70% and 89%.
  
  
  CONCLUSIONS
  Polarimetric measurements of the RNFL thickness can detect glaucomatous optic nerve damage in patients with visual field loss, and in some patients with preperimetric glaucomatous optic nerve damage. Considering the fast performance, easy handling, and low maintenance costs, RNFL polarimetry may be helpful in glaucoma diagnosis.
authors.affiliation: Department of Ophthalmology and University Eye Hospital, Friedrich-Alexander University Erlangen-Nürnberg at Erlangen, Germany.
authors.forename: F K
authors.initials: FK
authors.lastname: Horn
authors.forename: J B
authors.initials: JB
authors.lastname: Jonas
authors.forename: P
authors.initials: P
authors.lastname: Martus
authors.forename: C Y
authors.initials: CY
authors.lastname: Mardin
authors.forename: W M
authors.initials: WM
authors.lastname: Budde
mesh_terms: D000328:Adult; D002908:Chronic Disease; D003941:Diagnostic Techniques, Ophthalmological; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009900:Optic Nerve / Q000473:pathology*; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D012680:Sensitivity and Specificity; D058609:Visual Field Tests; D014794:Visual Fields