Color Doppler Imaging Analysis of Ocular Blood Flow Velocities in Normal Tension Glaucoma Patients: A Meta-Analysis

Table 2

Basic study data of the included studies.

Study	Country or region	Number of subjects; (NTG/control)	Gender (male : female); (NTG/control)	Ethnic composition; (NTG/control)	Mean age (years); (NTG/control)
[29]	Portugal	89/59	NA	NA	69.31 ± 12.1/71.44 ± 10.0
[43]	Portugal	62/48	NA	NA	70.4 ± 11/71.7 ± 9.5
[44]	Portugal	69/81	NA	NA	69.3 ± 11/64.6 ± 14
[45]	Portugal	63/55	NA	NA	69.7 ± 9.0/65.1 ± 11.0
[46]	Turkey	41/30	17 : 24/13 : 17	NA	56/53
[47]	UK	34/17	NA	NA	68.1 ± 8.7/65.2 ± 4.7
[48]	UK	25/26	NA	White 100%/White 100%	69.3 ± 8.9/65.7 ± 6.0
[49]	Italy	15/15	8 : 7/9 : 6	NA	64.7/65.8
[50]	Taiwan	13/25	9 : 4/24 : 1	NA	71.2/72.6
[51]	Italy	30/100^①	16 : 14/46 : 54	NA	46.4/48.9
[52]	Japan	10/13	NA	NA	NA/NA
[53]	Germany	20/20	8 : 12/11 : 9	NA	61.3 ± 12.97/60.2 ± 18.78
[54]	Italy	44/40	24 : 20/22 : 18	Caucasian 100%/Caucasian 100%	64.45 ± 6.91/62.75 ± 7.37
[55]	USA	15/15	NA^②	NA	61.4 ± 9.3/53.5 ± 8.8
[56]	Germany	15/15	6 : 9/6 : 9	NA	47 ± 8/41 ± 14
[57]	Switzerland	78/124	34 : 44/64 : 60	NA	NA
[58]	Germany	29/29	NA	NA	51 ± 10/44 ± 16
[30]	Germany	62/40	23 : 39/16 : 24	NA	57 ± 14/58 ± 9
[59]	Canada	23/28	NA	NA	64.8 ± 12.9/64.9 ± 12.4
[60]	Canada	42/35	15 : 27/16 : 19	NA	65.89 ± 11.15/61.87 ± 12.13
[61]	Belgium	28/22	NA	NA	72.8 ± 8.8/68.5 ± 8.9
[62]	Belgium	58/51	26 : 32/27 : 24	NA	70.9 ± 11.3/73.8 ± 13.3
[28]	China	60/44	31 : 29/20 : 24	NA	58.62 ± 13.05/57.41 ± 12.17

NA = not available.
^①That study divided the normal controls into two groups according to whether they were older than 50 years. In this meta-analysis, two groups were combined to make normal control group age-matched to NTG group.
^②That study only mentioned that there were 10 males and 20 females in all.