Relationship between visual field testing and scanning laser polarimetry in patients with a large cup-to-disk ratio

PURPOSE: To determine the relationship between quantitative nerve fiber lay er measurements and visual field testing in patients with large cup,to disk ratios. METHODS: Seventy-six patients with vertical cup,to, disk ratios by contour of at least 0.8 on stereoscopic photographs and 50 normal subjects were inc luded. One eye was randomly selected for study. All patients under, went st andard achromatic automated perimetry, short-wavelength automated perimetry , and retinal nerve fiber layer measurements with scanning laser polarimetr y. Analysis of variance was used to evaluate differences between the subjec t groups. Significance of pairwise comparisons was determined using the Tuk ey-Kramer multiple comparison test. RESULTS: Statistically significant differences in nerve fiber layer measure ments between patients with large cup,to,disk ratios and both abnormal stan dard achromatic automated perimetry and short,wavelength auto, mated perime try (n = 22) and patients with large cup,to-disk ratios and both normal sta ndard achromatic automated perimetry and short,wavelength automated perimet ry (n = 42) were found for superior nasal ratio, maximum modulation, ellips e modulation, and the linear discriminant function (Tukey-Kramer less than .05). There was no significant difference in patients with abnormal short-w avelength automated perimetry only (n = 9) as compared with patients with b oth normal standard achromatic automated perimetry and short, wavelength au tomated perimetry and patients with both abnormal standard achromatic autom ated perimetry and short-wavelength automated perimetry. Statistically sign ificant differences between the normal subjects and patients with large cup -to-disk ratios and both abnormal standard achromatic automated perimetry a nd shorts wavelength automated perimetry were found for all retinal nerve f iber layer parameters, with the exception of symmetry, superior ratio, and inferior ratio. CONCLUSION: Our results show considerable overlap in nerve fiber layer meas urements in eyes with large cup,to, disk ratio and abnormal visual fields a s compared with eyes with large cup-to-disk ratios and normal visual fields . This may limit the clinical usefulness of scanning laser polarimetry for detection of early glaucoma in patients with large cup,to,disk ratios. Long itudinal studies are needed to deter, mine if patients with large cup,to di sk ratios with normal standard achromatic automated perimetry and abnormal short-wavelength automated perimetry subsequently develop standard achromat ic automated perimetry defects and if scanning laser polarimetry can concur rently detect progression of nerve fiber layer damage. (C) 2001 by Elsevier Science Inc. All rights reserved.