Table 1
 The frequency of the compression of optic nerve by ICA
Number of patients
Number of eyes
No Compression
Compression (%)
Grade 0 (%)
Grade 1
Grade 2
NTG, normal tension glaucoma.
Control
52
104
68 (65.4%)
36 (34.6%)
22 (61.1%)
14 (38.9%)
NTG
54
103
52 (50.5%)
51 (49.5%)
33 (64.7%)
18 (35.3%)