title: Atypical retardation pattern in measurements of scanning laser polarimetry and its relating factors.
abstract: OBJECTIVE
  To assess the prevalence of atypical retardation pattern (ARP) in scanning laser polarimetry (SLP) with variable corneal compensation (VCC) and enhanced corneal compensation (ECC), and to evaluate the factors relating to typical scan score (TSS).
  
  
  METHODS
  Measurements of SLP-VCC, SLP-ECC, and the Humphrey field analyzer (HFA) were performed in 105 normal subjects and 82 open-angle glaucoma (OAG) patients. ARP was defined as an SLP image with TSS<80.
  
  
  RESULTS
  Prevalence of ARP with SLP-VCC was 13.3 and 14.6% in normal and OAG eyes, respectively, and that with SLP-ECC (2.9% and 1.2%) was lower than SLP-VCC (P<0.009). TSS with SLP-VCC was significantly correlated with age (partial correlation coefficient (PCC)=-0.22, P=0.003) and refractive error (PCC=0.26, P<0.001) after adjusting for each other. TSS with SLP-ECC was significantly correlated with neither age nor refractive error (PCC=-0.02, P=0.788; PCC=0.10, P=0.177, respectively). In OAG eyes, mean deviation (MD) of HFA was significantly correlated with TSS with SLP-VCC and SLP-ECC (PCC=0.35, P=0.001; PCC=0.23, P=0.039, respectively). In SLP-VCC, MD was significantly correlated with retinal nerve fibre layer (RNFL) thickness only after excluding eyes with ARP (P<0.001).
  
  
  CONCLUSIONS
  ARP in SLP-VCC measurements was found in more than 10% of normal or glaucomatous eyes, and TSS was significantly lower in older subjects, more myopic eyes, or eyes with more advanced glaucomatous damage. The presence of ARP disturbs the accuracy of RNFL thickness measurement by SLP-VCC. In SLP-ECC measurements, prevalence of ARP was considerably lower and TSS was not affected by age or refractive error, suggesting the advantages of ECC in clinical practices.
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: A
authors.initials: A
authors.lastname: Tomidokoro
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: C
authors.initials: C
authors.lastname: Mayama
authors.forename: M
authors.initials: M
authors.lastname: Aihara
authors.forename: G
authors.initials: G
authors.lastname: Tomita
authors.forename: N
authors.initials: N
authors.lastname: Shoji
authors.forename: M
authors.initials: M
authors.lastname: Araie
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000502:physiology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009901:Optic Nerve Diseases / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D012165:Retinal Ganglion Cells / Q000473:pathology; D057109:Scanning Laser Polarimetry