Table 6 Relationship between intra-operative visual-evoked potential (VEP) and post-operative visual function

Study (Year)

Intra-operative VEP

Post-operative

Visual Acuity n (%)

Post-operative

Visual Fields n (%)

Notes

Improved

Stable

Worsened

Improved

Stable

Worsened

Feng et al. (2019) [18]

Improved

0 (0)

1 (100)

0 (0)

0 (0)

1 (100)

0 (0)

Sensitivity and specificity of VEP amplitude in detecting changes in visual field outcomes are 75% and 79%, respectively

Stable

27 (87)

4 (13)

30 (97)

1 (3)

Worsened (transient)

1 (17)

2 (33)

3 (50)

2 (33)

3 (50)

1 (17)

Worsened (permanent)

2 (50)

1 (25)

1 (25)

1 (25)

1 (25)

2 (50)

Qiao et al. (2019) [19]

Did not measure post-operative outcomes

Toyama et al. (2018) [20]

Improved

3 (100)

0 (0)

0 (0)

1 (33)

2 (66)

0 (0)

No significant relationship observed between VEP and visual field outcome

Stable

11 (53)

10 (48)

0 (0)

9 (43)

12 (57)

0 (0)

Worsened (transient)

6 (66)

3 (33)

0 (0)

5 (56)

4 (44)

0 (0)

Worsened (permanent)

3 (50)

3 (50)

0 (0)

1 (17)

5 (83)

0 (0)

Kamio et al. (2014) [7]

Improved

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

No statistical analysis performed

Stable

11 (48)

12 (52)

0 (0)

5 (22)

18 (78)

0 (0)

Worsened (transient)

2 (50)

2 (50)

0 (0)

2 (50)

2 (50)

0 (0)

Worsened (permanent)

0 (0)

1 (100)

0 (0)

0 (0)

0 (0)

1 (100)

Houlden et al. (2014) [9]

Did not measure post-operative outcomes

Chung et al (2012) [24]

Improved

4 (22)

13 (68)

2 (11)

13 (68)

4 (22)

2 (11)

No association found between intraoperative VEP waveforms and post-operative visual acuity or visual fields

Stable

13 (20)

42 (66)

9 (14)

39 (64)

17 (26)

8 (13)

Worsened (transient /permanent)

5 (42)

5 (42)

2 (17)

6 (50)

3 (25)

3 (25)

Chacko et al. (1996) [25] Group A

Improved

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

There was statistically significant improvement in post-operative visual field testing between the test group A (with VEP monitoring) and the control group B (without VEP monitoring)

There was no statistical difference in visual acuity between the two groups

Stable

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

Worsened (transient)

n/a

n/a

n/a

34 (77)

10 (23)

0 (0)

Worsened (permanent)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

Post-operative Visual Function^a

Improved n (%)

Stable n (%)

Worsened n (%)

Nishimura et al. (2018) [21]

Improved

0 (0)

0 (0)

0 (0)

“Intraoperative monitoring of VEP predicts postoperative visual function, and a reversible change in VEP indicates that visual function will be preserved”(2)

Stable

62 (50)

62 (50)

0 (0)

Worsened (transient)

8 (31)

18 (69)

0 (0)

Worsened (permanent)

0 (0)

8 (100)

0 (0)

Luo et al.^b(2015) [23]

Improved

0 (0)

0 (0)

0 (0)

Intra-operative VEP has a specificity of 96% and a negative predictive value of 90% in detecting post-operative visual functionPreservation of VEPs predicted preserved visual function

Stable

8 (16)

36 (72)

6 (12)

Worsened (transient)

0 (0)

10 (100)

0 (0)

Worsened (permanent)

0 (0)

2 (2)

0 (0)

Sasaki et al.^b (2010) [6]

Improved

1 (100)

0

0 (0)

“Changes in intraoperative VEP findings, especially in the VEP amplitude, were well correlated with postoperative visual function”(3)

Stable

17 (10)

150 (89)

2 (1)

Worsened (transient)

1 (33)

2 (67)

0

Worsened (permanent)

0

0

14 (100)

Kurozumi et al. (2017) [22]

80% of patients with pre-operative visual disturbances had an improved visual acuity immediately after surgery 80% of patients had improved visual fields immediately after surgery