Evaluation of the circulation in the retina, peripapillary choroid and optic disk in normal-tension glaucoma

Computerized image analysis, including fluorescein angiography, was used to evaluate the retinal, choroidal and optic disk blood flow in 16 patients with normal-tension glaucoma (NTG) and to correlate this measurement with visual fields, retinal vessel width, optic disk pallor and blood pressure (BP). The angle of the ascending slope of the fluorescein dye curve was measured as an index of blood flow from the densitometric and time curves of the fluorescein angiograms in the optic disk, peripapillary choroid, retinal artery and vein for each quadrant. While the ascending slope as well as the retinal vessel width were most reduced in the inferior and nasal regions, the mean threshold was lowest in the superior and nasal quadrants. There were positive significant correlations between artery width and threshold value, between angles of slopes and pallor. In addition, systolic BP had a negative correlation with pallor, and diastolic BP had a positive one with slope in the choroid. These results indicated the probable association of a decrease in retinal, choroidal and optic disk blood flow in the inferior and nasal quadrants as well as vessel width in the inferior nasal quadrant with visual field loss in the superior quadrant, and also demonstrated an increasing blood flow for enlargement of pallor. A decrease in BP was found to be related to reduced blood flow in choroid and optic disk impairment.