The Role of Ancillary Testing in the Diagnostic Evaluation of Normal-Tension Glaucoma

Abstract

Abstract: : Purpose: To prospectively evaluate the incidence of hemodynamically significant carotid artery stenosis and hematologic abnormalities among persons with NTG and POAG. Methods: Complete eye examination, automated achromatic perimetry, carotid Doppler ultrasonography, and serum laboratory testing (ESR, CBC, VDRL, FTA-ABS) were performed in all patients. Scanning laser Doppler flowmetry (SLDF) was performed using the Heidelberg retinal flowmeter to generate capillary perfusion measurements in the superotemporal and inferotemporal peripapillary retina. Results: 20 eyes of 20 patients (10 POAG, 10 NTG) were enrolled (mean age 57.0 ± 24.4 years, range 18–89). No significant differences in mean age (P = 0.85), intraocular pressure (P = 0.46), and visual field MD (P = 0.71) were observed between the POAG and NTG groups. No significant differences in mean peripapillary blood flow assessed by SLDF (P = 0.08), incidence of clinically significant (>70%) carotid stenosis (20% POAG, 20% NTG, P = 0.71), mean ESR (P = 0.92), mean hemoglobin (P = 0.42), or incidence of positive FTA-ABS (0% POAG, 0% NTG) were observed between the 2 groups. Severity of glaucomatous damage as determined by visual field MD did not correlate with the magnitude of carotid artery stenosis (R² = 0.12, P = 0.62; R² = 0.33, P = 0.24) or mean SLDF blood flow (R² = 0.29, P = 0.11; R² = 0.01, P = 0.75) for the POAG and NTG groups, respectively. Conclusions: The incidence of carotid stenosis and hematologic abnormalities in NTG and POAG are similar. These data suggest that routine ancillary testing in the diagnostic evaluation of NTG is of little value.

Keywords: optic flow • intraocular pressure • optic disc