Table 6.
Comparison of postoperative flash VEP and ff-ERG parameters between subgroups IB and IIB
| Parameters |
Subgroup IB (n = 7)
Median (IQR) |
Subgroup IIB (n =7)
Median (IQR) |
P -value * | |
|---|---|---|---|---|
| Electrophysiology | Parameters at the 1-month postoperative follow-up | |||
| Flash VEP responses | P1 latency (ms) | 66.6 (16.7) | 74.0 (3.4) | 0.441 |
| P1 amplitude (µV) | 9.2 (5.9) | 8.5 (9.3) | 1.000 | |
| P2 latency (ms) | 133.6 (29.8) | 113.3 (68.6) | 0.569 | |
| P2 amplitude (µV) | 5.5 (3.8) | 6.8 (11.3) | 0.897 | |
| ff-ERG responses | Scotopic a-wave latency (ms) | 25.3 (8.5) | 32.0 (20.3) | 0.897 |
| Scotopic a-wave amplitude (µV) | 14.5 (8.3) | 12.3 (9.8) | 0.522 | |
| Scotopic b-wave latency (ms) | 56.9 (9.6) | 54.3 (17.9) | 0.749 | |
| Scotopic b-wave amplitude (µV) | 40.2 (28.9) | 20.6 (16.6) | 0.308 | |
| Photopic a-wave latency (ms) | 29.4 (9.1) | 20.0 (9.7) | 0.097 | |
| Photopic a-wave amplitude (µV) | 4.4 (8.5) | 7.7 (6.2) | 0.441 | |
| Photopic b-wave latency (ms) | 34.9 (15.1) | 39.0 (31.7) | 0.522 | |
| Photopic b-wave amplitude (µV) | 14.1 (13.0) | 14.1 (15.7) | 0.653 | |
| Oscillatory potential (µV) | 3.3 (2.3) | 3.9 (3.0) | 0.569 | |
| Electrophysiology | Parameters at the 3-month postoperative follow-up | |||
| Flash VEP responses | P1 latency (ms) | 71.0 (3.2) | 75.1 (9.7) | 0.484 |
| P1amplitude (µV) | 10.4 (18.9) | 7.8 (3.3) | 0.110 | |
| P2 latency (ms) | 137.1 (37.0) | 121.0 (20.3) | 1.000 | |
| P2 amplitude (µV) | 10.3 (8.2) | 8.5 (7.6) | 0.610 | |
| ff-ERG responses | Scotopic a-wave latency (ms) | 26.1 (4.7) | 20.8 (10.6) | 0.201 |
| Scotopic a-wave amplitude (µV) | 20.7 (19.5) | 20.3 (20.3) | 0.610 | |
| Scotopic b-wave latency (ms) | 48.0 (6.4) | 46.7 (2.0) | 0.337 | |
| Scotopic b-wave amplitude (µV) | 37.1 (22.9) | 39.3 (37.8) | 0.795 | |
| Photopic a-wave latency (ms) | 21.4 (7.1) | 21.4 (6.5) | 1.000 | |
| Photopic a-wave amplitude (µV) | 8.0 (8.3) | 7.8 (3.6) | 0.849 | |
| Photopic b-wave latency (ms) | 33.8 (7.6) | 39.6 (7.4) | 0.250 | |
| Photopic b-wave amplitude (µV) | 17.1 (15.3) | 10.3 (5.6) | 0.522 | |
| Oscillatory potential (µV) | 4.9 (3.4) | 4.3 (2.4) | 0.704 | |
Abbreviations: flash VEP, flash-visual evoked potential; ff-ERG, full-field electroretinogram; n, number of participants; P1, first positive peak in the VEP waveform; P2, second positive peak in the VEP waveform; ms, milliseconds; µV, microvolts; IQR, interquartile range; PVR, proliferative vitreoretinopathy (*the Mann–Whitney U test was used). Note: IQR is the region between the 75th and 25th percentile; Subgroup IB, subgroup in the control group with established preoperative PVR grade C; Subgroup IIB, subgroup in the intervention group with established preoperative PVR grade C.