Diffuse and localized nerve fiber layer loss measured with a scanning laser polarimeter: Sensitivity and specificity of detecting glaucoma

Purpose: To differentiate normal from diseased retinal nerve fiber layers ( NFL) using a new method of analyzing polarimetry data that specifically tar gets patterns of diffuse and localized NFL loss. Methods: The NFL from a sample of 34 patients with primary open-angle glauc oma (POAG), 34 patients with ocular hypertension, and 34 normal subjects we re imaged using a scanning laser polarimeter (GDx; Laser Diagnostic Technol ogies, Inc., San Diego, CA). Diffuse loss was defined as a reduction in the peak-to-trough amplitude of the double-hump NFL pattern, and localized los s was defined as a lowering of the correlation of thickness values between local regions shown previously to correspond in normal subjects. Results: Significant differences were found between the groups of normal su bjects, patients with hypertension, and patients for both the amplitude and the correlational measures. The sensitivity and specificity calculated usi ng optimal criterion values were 94% and 91%, respectively. Conclusions: These results suggest that NFL analysis targeting specific pat terns of loss may be beneficial for differentiating normal NFL patterns fro m diseased NFL patterns, as well as for identifying patients at high risk.