Blood flow in retinal vessels of normal-tension glaucoma with or without a history of optic disc hemorrhages

PURPOSE: To evaluate blood flow in retinal vessels of normal-tension glaucoma (NTG) with or without a history of optic disc hemorrhages (DH) and compare it with that in non-glaucomatous eyes using scanning laser fluorescein video angiography. METHODS: We enrolled 14 eyes of 14 NTG patients with a history of DH (DH (+) group), 12 eyes of 12 NTG patients without history of DH (DH (-) group), and 10 eyes from 10 non-glaucomatous patients matched for age, intraocular pressure, and systemic blood pressure. No statistically significant difference was observed between the DH (+) and DH (-) groups of NTG in the global indices of the Humphrey visual field. Fluorescein angiography was performed using a scanning laser ophthalmoscope with an argon blue laser. A series of approximately 100 consecutive video images at 1/2 second intervals from just before the dye appearance in the central retinal artery was loaded into an external personal computer system. Based on this acquired image series, we obtained fluorescein filling curves for 10 x 10 pixel measuring areas placed on each of the superior-temporal and inferior-temporal branch retinal arteries and veins at 1/5 papillary diameter from the disc edge. In each vessel, time to the highest fluorescein intensity (peak time, sec) and the time constant of the filling curve (tau, sec) were obtained. Time difference between the peak times in vein and artery (peak time difference) was also calculated. RESULTS: Statistically significant differences were observed among the three groups in the peak time of inferior-temporal artery and vein, and superior-temporal vein (ANOVA, p < 0.01). Also there were statistically significant differences in the tau of all vessels (ANOVA, p < 0.05). No statistically significant differences were observed in the peak time differences. By multivariate analysis, the DH (+) and DH (-) groups of NTG showed significantly longer peak times and tau s than did the non-glaucomatous eyes (p < 0.05). However, no statistically significant differences were observed in any parameters between the DH (+) and DH (-) groups of NTG. CONCLUSIONS: In NTG, dye filling rate in both the central retinal arteries and veins seems to be delayed. However, this delay does not differ between DH (+) and DH (-) groups.