Correlating structure with function in end-stage glaucoma

BACKGROUND AND OBJECTIVE: To correlate structure and function in eyes with end-stage glaucoma. PATIENTS AND METHODS: Fifty-six eyes of 48 patients with glaucoma presenting with end-stage glaucoma underwent scanning laser polarimetry (SLP) imaging using a commercially available GDx-variable corneal compensator unit (GDx-VCC; Laser Diagnostics Technologies, Inc., San Diego, CA). End-stage glaucoma was defined by both disc appearance and standard automated perimetry visual field criteria. Standard automated perimetry parameters included: mean deviation, pattern standard deviation, and total deviation plot. GDx parameters included: TSNIT average, superior average, inferior average, TSNIT standard deviation, and nerve fiber indicator. RESULTS: The visual field mean deviation was -26.75 +/- 3.50 dB. The remaining retinal nerve fiber layer measured in this group of eyes was: TSNIT average, 29.76 +/- 5.81 mu m; superior average, 30.76 +/- 6.25 mu m; and inferior average, 31.14 +/- 7.20 mu m. A low structure-function correlation was found when analyzing separately the superior and inferior hemifields (R-2 0.00001, R-2 = 0.0016, respectively). CONCLUSIONS: In eyes with end-stage glaucoma, very thin but existing retinal nerve fiber layer is found on SLP. Such values rarely dropped below 10 to 20 pm. A flattening of the GDx TSNlT pattern was seen, and the correlation between structure and function was not evident.