Table 2. Correlations between flow parameters for ophthalmic artery and central retinal artery, contrast sensitivity, and visual field parameters.

		Flow parameters vs. contrast sensitivity		Flow parameters vs. visual field
Artery	Doppler ultrasound parameter	Correlation coefficient†	p-value	Correlation coefficient†	p-value
OA	SFV	-0.35	0.03	-0.34	0.04
	DFV	-0.44	0.008	-0.26	0.13
	VMEAN	-0.43	0.009	-0.39	0.01
	RI	0.28	0.09	0.20	0.23
	PI	0.33	0.04	0.25	0.13
CRA	SFV	-0.36	0.030	0.02	0.02
	DFV	-0.55	<0.001	0.02	0.02
	VMEAN	-0.23	0.18	0.12	0.12
	RI	0.50	0.002	0.22	0.19
	PI	0.31	0.06	0.09	0.59

OA = ophthalmic artery; CRA = central retinal artery; SFV = peak systolic flow velocity; DFV = end diastolic flow velocity; VMEAN = mean flow; RI = resistivity index; PI = pulsatility index; ^†Spearman coefficient of correlation