Discrimination between normal and glaucomatous eyes with the Topographic Scanning System: a preliminary report.

BACKGROUND AND

OBJECTIVE

To evaluate the ability of the Topographic Scanning System (TopSS; Laser Diagnostic Technologies, San Diego, CA) to differentiate individuals with glaucoma from normal subjects.

PATIENTS AND

METHODS

The subjects were divided into two groups: primary open-angle glaucoma and normal. All individuals underwent a complete ophthalmic evaluation, a 24-2 full threshold Humphrey visual field evaluation, and a TopSS examination. Cut-off points were selected, receiver operator characteristic (ROC) curves were created, and sensitivity and specificity were calculated for individual TopSS parameters and combinations of variables using multivariate analysis.

RESULTS

One hundred twelve patients with glaucoma and 88 normal individuals were enrolled in the study. The best TopSS individual parameters were: average disc diameter (sensitivity: 64%, specificity: 89%, area under ROC curve: 0.824), total disc area (sensitivity: 85%, specificity: 66%, area under ROC curve: 0.802), and cup area (sensitivity: 69%, specificity: 85%, area under ROC curve: 0.797). The multivariate analysis resulted in an area under the ROC curve of 0.91 (sensitivity: 90%, specificity: 81%).

CONCLUSIONS

This preliminary report suggests that the use of a multivariate discriminant formula may enhance the ability to differentiate individuals with glaucoma from normal subjects with the TopSS, with high sensitivity and specificity. Further studies investigating a random population are needed to test the validity of this formula.