title: Correlation between scanning laser polarimetry with and without enhanced corneal compensation and high-definition optical coherence tomography in normal and glaucomatous eyes.
abstract: OBJECTIVE
  To assess the relationship between high-definition optical coherence tomography (HD-OCT) and scanning laser polarimetry (SLP) with variable (VCC) and enhanced (ECC) corneal compensation in measuring peripapillary retinal nerve fibre layer (RNFL) thickness in healthy eyes and those with early-to-moderate glaucomatous VF loss.
  
  
  METHODS
  Healthy volunteers and patients with glaucoma who met the eligibility criteria were enrolled in this prospective, cross-sectional, and observational study. Subjects underwent complete ophthalmologic examination, automated perimetry, SLP-ECC, SLP-VCC and HD-OCT. SLP parameters were recalculated in 90 degrees segments (quadrants) in the calculation circle to be compared. Pearson correlation coefficients and Lin's concordance correlation coefficients were calculated. The p-values < 0.05 were considered statistically significant.
  
  
  RESULTS
  Fifty-five normal volunteers (mean age 59.1 years) and 33 patients with glaucoma (mean age 63.8 years) were enrolled. In the glaucoma group, 18 patients (54.5%) had MD ≥ -6.0 dB (early glaucoma) and 15 patients (45.4%) had MD between -6.01 and -12.0 dB (moderate glaucoma). The best correlation between HD-OCT and SLP was found in the superior quadrant thickness, r = 0.74 (0.62-0.82) (p < 0.0001) with SLP-VCC and in the average thickness, r = 0.80 (0.71-0.86) (p < 0.0001) and the superior quadrant thickness r = 0.80 (0.71-0.87) (p < 0.0001) with SLP-ECC. Concordance correlation coefficients obtained for every parameter in our study between HD-OCT and SLP-VCC and between HD-OCT and SLP-ECC were poor.
  
  
  CONCLUSIONS
  Our results suggest that HD-OCT parameters of RNFL thickness are significantly higher than SLP-VCC and SLP-ECC parameters, and therefore those thickness values are not interchangeable. The HD-OCT and SLP methods are well correlated but concordance is poor. The difference plots show a lack of agreement that changes as a proportion of the mean.
authors.affiliation: Unidad de Glaucoma, Hospital General del S.A.S. de Jerez, Jerez, Cádiz, Spain. javbcs@jbcs.e.telefonica.net
authors.forename: J
authors.initials: J
authors.lastname: Benítez-del-Castillo
authors.forename: A
authors.initials: A
authors.lastname: Martinez
authors.forename: T
authors.initials: T
authors.lastname: Regi
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005902:Glaucoma, Open-Angle / Q000473:pathology*; D006801:Humans; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D011446:Prospective Studies; D012164:Retinal Diseases / Q000473:pathology*; D057109:Scanning Laser Polarimetry / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000379:methods*