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 GDxvariable 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 µm; superior average, 30.76 ± 6.25 µm; and inferior average, 31.14 ± 7.20 µm. A low structure-function correlation was found when analyzing separately the superior and inferior hemifields (R2 = 0.00001, R2 = 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 µm. A flattening of the GDx TSNIT pattern was seen, and the correlation between structure and function was not evident. [ Ophthalmic Surg Lasers Imaging 2006;37:218-223.] AUTHORS From the Department of Ophthalmology (EZB, AH), Hebrew University-Hadassah Medical Center, Jerusalem, Israel; and the L. V. Prasad Eye Institute (RS, CG, AU, RT), Hyderabad, India. Accepted for publication October 21, 2005. Dr. Blumenthal has received research support from Laser Diagnostic Technologies, Inc., San Diego, CA. Address reprint requests to Eytan Z. Blumenthal, MD, Department of Ophthalmology, Hadassah University Hospital, P. O. Box 12000, Jerusalem 91120, Israel.