Table 1. Comparison of subject characteristics according to the myopic degree and optic disc rotation direction.
| Variables | Overall (n = 150) |
Degree of myopia | Optic disc rotation direction | ||||
|---|---|---|---|---|---|---|---|
| Non-high myopia (n = 98) |
High myopia (n = 52) |
p value* | Superior (n = 79) |
Inferior (n = 71) |
p value† | ||
| Age (yrs) | 23.39 ± 3.85 | 23.80 ± 3.66 | 22.62 ± 4.11 | 0.074 | 23.44 ± 3.93 | 23.32 ± 3.78 | 0.851 |
| Sex (male/female) | 99 / 51 | 64 / 34 | 35 /17 | 0.476 | 55 / 24 | 44 / 27 | 0.389 |
| SE refractive error (D) | -5.34 ± 2.72 | -3.72 ± 1.40 | -8.38 ± 1.83 | < 0.001 | -4.96 ± 2.49 | -5.76 ± 2.91 | 0.077 |
| IOP (mmHg) ‡ | 14.87 ± 2.44 | 14.70 ± 2.35 | 15.17 ± 2.61 | 0.265 | 14.38 ± 2.58 | 15.41 ± 2.17 | 0.009 |
| Axial length (mm) | 26.05 ± 1.25 | 25.46 ± 0.98 | 27.14 ± 0.96 | < 0.001 | 25.96 ± 1.23 | 26.14 ± 1.29 | 0.379 |
| Central corneal thickness (μm) | 558.21 ± 35.37 | 558.34 ± 37.64 | 557.96 ± 31.01 | 0.951 | 555.72 ± 30.52 | 260.97 ± 40.14 | 0.373 |
| Disc area (mm2) | 1.86 ± 0.40 | 1.88 ± 0.45 | 1.80 ± 0.25 | 0.071 | 1.85 ± 0.33 | 1.87 ± 0.46 | 0.818 |
| Vertical CDR | 0.48 ± 0.15 | 0.49 ± 0.16 | 0.45 ± 0.15 | 0.081 | 0.45 ± 0.14 | 0.61 ± 0.17 | 0.061 |
| Ovality index | 1.31 ± 0.13 | 1.31 ± 0.12 | 1.33 ± 0.14 | 0.340 | 1.31 ± 0.13 | 1.32 ± 0.12 | 0.609 |
| Optic disc rotation degree (°) | 1.57 ± 15.60 | -0.31 ± 15.07 | 5.12 ± 16.10 | 0.042§ | -11.95 ± 4.66 | 16.62 ± 7.60 | < 0.001§ |
| Area of β-PPA (mm2) | 0.96 ± 0.42 | 0.90 ± 0.41 | 1.08 ± 0.41 | 0.010 | 0.86 ± 0.37 | 1.07 ± 0.45 | 0.002 |
| Average pRNFL thickness (μm) | 98.71 ± 7.97 | 100.95 ± 6.79 | 94.48 ± 8.37 | < 0.001 | 99.27 ± 7.09 | 98.08 ± 8.86 | 0.367 |
| Whole en face vessel density of RPC segment (%) | 55.16 ± 2.40 | 55.74 ± 2.24 | 54.06 ± 2.35 | < 0.001 | 55.46 ± 2.08 | 54.82 ± 2.69 | 0.100 |
| Inside disc vessel density (%) | 47.66 ± 8.13 | 46.85 ± 8.51 | 49.17 ± 7.21 | 0.097 | 48.79 ± 7.99 | 46.39 ± 8.15 | 0.073 |
| Superficial peripapillary microvascular density (%) | 62.14 ± 5.47 | 63.03 ± 2.56 | 60.49 ± 3.46 | < 0.001 | 62.38 ± 2.90 | 61.88 ± 3.39 | 0.336 |
| Deep peripapillary microvascular density (%) | 73.76 ± 4.02 | 73.60 ± 4.22 | 74.05± 3.64 | 0.525 | 75.05± 3.71 | 72.32± 3.89 | < 0.001 |
SE = spherical equivalent; D = diopters; IOP = intraocular pressure; CDR = cup-to-disc ratio; PPA = peripapillary atrophy; pRNFL = peripapillary retinal nerve fiber layer; RPC = radial peripapillary capillary.
* Comparisons between the non-high myopia and high myopia groups using an independent-t test or chi-square test as appropriate.
† Comparisons between the superior rotation and inferior rotation groups using an independent-t test or chi-square test as appropriate.
‡ All IOP measurements were made between 4:00 and 6:00 pm.
§ The comparison was done with the unsigned value.