Table 2. Comparisons of six optic disc parameters among four optic disc types predicted by the Glaucoma Stereo Analysis Study classification.
| pFI | pGE | pMY | pSS | P value† | |
|---|---|---|---|---|---|
| N (%) | |||||
| 46 (24.6) | 36 (19.3) | 70 (37.4) | 35 (18.7) | ||
| Rim-disc ratio of section 1 (temporal 90°) | |||||
| Mean ± SD | 0.120 ± 0.033 | 0.074 ± 0.031 | 0.042 ± 0.033 | 0.053 ± 0.038 | <0.0001¶ |
| 95% CI | 0.110–0.130 | 0.063–0.085 | 0.034–0.050 | 0.041–0.064 | |
| P values‡, against pGE | <0.0001** | — | — | — | |
| against pMY | <0.0001** | <0.0001** | — | — | |
| against pSS | <0.0001** | 0.0076* | 0.1311 | — | |
| Rim-disc ratio of section 4 (nasal 90°) | |||||
| Mean ± SD | 0.185 ± 0.064 | 0.134 ± 0.047 | 0.246 ± 0.067 | 0.181 ± 0.072 | <0.0001¶ |
| 95% CI | 0.167–0.204 | 0.118–0.150 | 0.230–0.262 | 0.157–0.206 | |
| P values‡, against pGE | 0.0003** | — | — | — | |
| against pMY | <0.0001** | <0.0001** | — | — | |
| against pSS | 0.7794 | 0.0018* | <0.0001** | — | |
| Mean cup depth, mm | |||||
| Mean ± SD | 0.192 ± 0.045 | 0.300 ± 0.062 | 0.170 ± 0.067 | 0.190 ± 0.112 | <0.0001¶ |
| 95% CI | 0.179–0.205 | 0.280–0.321 | 0.154–0.186 | 0.151–0.228 | |
| P values‡, against pGE | <0.0001** | — | — | — | |
| against pMY | 0.1072 | <0.0001** | — | — | |
| against pSS | 0.8948 | <0.0001** | 0.1817 | — | |
| Height variation contour, mm | |||||
| Mean ± SD | 0.484 ± 0.155 | 0.413 ± 0.185 | 0.774 ± 0.209 | 0.487 ± 0.311 | <0.0001¶ |
| 95% CI | 0.438–0.530 | 0.351–0.476 | 0.724–0.823 | 0.380–0.593 | |
| P values‡, against pGE | 0.1453 | — | — | — | |
| against pMY | <0.0001** | <0.0001** | — | — | |
| against pSS | 0.9497 | 0.1542 | <0.0001** | — | |
| Disc tilt angle, degrees | |||||
| Mean ± SD | 8.04 ± 6.37 | 2.77 ± 7.82 | 22.14 ± 8.10 | -1.84 ± 9.56 | <0.0001¶ |
| 95% CI | 6.15–9.93 | 0.12–5.42 | 20.21–24.07 | -5.13–1.44 | |
| P values‡, against pGE | 0.0033* | — | — | — | |
| against pMY | <0.0001** | <0.0001** | — | — | |
| against pSS | <0.0001** | 0.0157 | <0.0001** | — | |
| Rim decentering absolute value | |||||
| Mean ± SD | 0.578 ± 0.272 | 0.375 ± 0.250 | 0.413 ± 0.277 | 0.403 ± 0.226 | 0.0013¶ |
| 95% CI | 0.497–0.959 | 0.291–0.459 | 0.347–0.479 | 0.326–0.480 | |
| P values‡, against pGE | 0.0006** | — | — | — | |
| against pMY | 0.0011** | 0.4768 | — | — | |
| against pSS | 0.0032* | 0.6528 | 0.8499 | — |
P values (†) are calculated among four types of optic disc appearances by one-way analysis of variance (ANOVA) (†) followed by comparison between each pair of two types of optic disc appearances using the post-hoc Student t-test (‡). The ¶ indicates significance levels of 5% and 1% by one-way ANOVA, respectively. In the post-hoc test, based on Bonferroni 's method to correct multiple comparisons, P<0.0083 and P<0.0017 are considered to be significance levels of 5% (*) and 1% (**), respectively.
The pFI, pGE, pMY, and pSS indicate respective types of optic disc appearances predicted by the GSAS classification formulas.
SD, standard deviation; 95% CI, 95% confidence interval; pGE, formula-predicted focal ischemia; pMY, formula-predicted myopic glaucomatous; pSS, formula-predicted senile sclerotic; pGE, formula-predicted generalized enlargement.