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 targets patterns of diffuse and localized NFL loss.

METHODS

The NFL from a sample of 34 patients with primary open-angle glaucoma (POAG), 34 patients with ocular hypertension, and 34 normal subjects were imaged using a scanning laser polarimeter (GDx; Laser Diagnostic Technologies, 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 loss 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 subjects, patients with hypertension, and patients for both the amplitude and the correlational measures. The sensitivity and specificity calculated using optimal criterion values were 94% and 91%, respectively.

CONCLUSIONS

These results suggest that NFL analysis targeting specific patterns of loss may be beneficial for differentiating normal NFL patterns from diseased NFL patterns, as well as for identifying patients at high risk.