Scanning laser polarimetry in a selected group of patients with glaucoma and normal controls

- PURPOSE: To evaluate the ability of scanning laser polarimetry to discrim inate between subjects with glaucoma with specific patterns of visual field defect and normal controls. - METHODS: This cross,sectional, prospective study in a glaucoma practice, focused on subjects with glaucoma with predefined types of visual field def ect, including advanced (group A, n = 14), localized (group L, n = 46), or mixed (diffuse and localized) defects (group M, n = 22) and normal controls (n = 32). Scanning laser polarimetry was performed in one study eye per su bject. Two methods of analysis were used: a subjective analysis, in which e xamination printouts with the image of the optic disk manually blocked were classified by two observers masked to the diagnosis, and a logistic regres sion analysis of the retardation parameters included in the printouts. - RESULTS: The observers correctly identified 97% of the controls and 68% o f subjects with glaucoma (overall correct classification of 77%), with 93%, 70%, and 47% of patients from groups A, L, and M, respectively, being corr ectly identified. The best discrimination obtained with the logistic regres sion correctly identified 69% of controls and 94% of glaucoma subjects (ove rall correct classification of 87%). The performance was only slightly bett er for cases from group A compared with L and M. - CONCLUSIONS: Subjective assessment of the scanning laser polarimetry stan dard printout of single eyes might not be sensitive enough to detect cases of glaucoma with localized or milder mixed types of visual field defect. Th e discriminating ability of scanning laser polarimetry im, proves slightly when logistic regression analysis is employed. (C) 2001 by Elsevier Science Inc. All rights reserved.