Table 3. Subgroup analysis of preoperative and postoperative topographic features including central macular thickness according to the clinical grading of epiretinal membrane.
| Parameters | Grade 1 (n=19) | Grade 2 (n=27) | Grade 3 (n=17) | P-valuea |
|---|---|---|---|---|
| Area under major vessels (number of pixels) | ||||
| Preoperative | 17843.8±2264.0 | 16067.6±3284.8 | 15596.3±3620.1 | 0.073 |
| Postoperative | 18484.1±2977.6 | 16793.3±3471.5 | 16997.2±3819.3 | 0.235 |
| P-value (pre-post)b | 0.199 | 0.034* | 0.002* | |
| P-value (pre-fellow)c | 0.354 | 0.013* | 0.011* | |
| P-value (post-fellow)c | 0.948 | 0.031* | 0.048* | |
| Macroscopic diverging angle (degree) | ||||
| Preoperative | 75.7±8.2 | 72.1±12.1 | 72.8±12.9 | 0.552 |
| Postoperative | 77.7±7.7 | 75.1±11.2 | 75.7±12.8 | 0.721 |
| P-value (pre-post)b | 0.002* | <0.001* | 0.001* | |
| P-value (pre-fellow)c | 0.594 | 0.134 | 0.264 | |
| P-value (post-fellow)c | 0.921 | 0.763 | 0.968 | |
| Central macular thickness (μm) | ||||
| Preoperative | 344.5±79.5 | 395.4±110.6 | 468.6±77.7 | 0.002* |
| Postoperative | 295.1±48.7 | 322.5±62.4 | 339.9±80.8 | 0.122 |
| P-value (pre-post)b | 0.034* | 0.001* | <0.001* | |
All values are given as mean±s.d.; number of pixels=pixel × pixel.
a
P-value by one-way ANOVA between different grades of epiretinal membrane.
b
P-value by paired t-test between pre- and postoperative features.
c
P-value by paired t-test between epiretinal membrane eyes and fellow eyes of pre- and postoperative features.
*P-value <0.05.