Table 2.
Visual and ocular findings of the study subjects
| Parameters | Levels | Groups | P-value | ||||
|---|---|---|---|---|---|---|---|
| Twins (n = 180) | Non- twins (n = 182) | ||||||
| Monozygotic (n = 54) | Dizygotic (n = 126) | P-value | Total | ||||
| SE (D) | Mean ± SD | 0.976 ± 1.91 | 0.789 ± 1.97 | 0.407¥ | 0.819 ± 1.963 | 0.49 ± 2.33 | 0.041¥ |
| Median (Range) | 0.94 (-3.00 to 8.37) | 1.00 (-9.50 to 7.62) | 0.875 (-9.5 to 8.37) | 0.75 (-12.0 to 8.0) | |||
| Anisometropia (SE ≥ 1.50D) | Yes | 3 (5.5%) | 4 (3.2%) | 0.904** | 7 (3.9%) | 13 (7.1%) | 0.25** |
| High Anisometropia (SE ≥ 3.00D) | Yes | 1 (1.8%) | 2 (1.6%) | 0.455* | 3 (1.7%) | 2 (1.1%) | 0.67* |
| Astigmatism (%) | WTR | 68 (62.9%) | 160 (63.5%) | 0.552* | 228 (63.4%) | 201 (55.2%) | 0.25* |
| ATR | 4 (4.4%) | 6 (2.4%) | 10 (2.7%) | 17 (4.7%) | |||
| Oblique | 2 (1.7%) | 2 (0.8%) | 4 (1.1%) | 4 (1.1%) | |||
| No Astigmatism | 34 (31.0) | 84 (33.3%) | 118 (32.8%) | 142 (39.0%) | |||
| Mirror Image of refractive error (%) | 3 (5.6%) | 2 (1.6%) | 0.32* | 5 (2.8%) | - | - | |
| BCVA (LogMAR) | Mean ± SD | 0.07 ± 0.16 | 0.06 ± 0.14 | 0.557¥ | 0.07 ± 0.16 | 0.03 ± 0.08 | < 0.001¥ |
| Median (Range) | 0.0 (0.0 to 1.0) | 0.0 (-0.12 to 1.0) | 0 (-0.12 to 1) | 0 (0 to 0.7) | |||
| Amblyopia (%) | Yes | 31 (57.4%) | 36 (28.6%) | 0.004** | 67 (37.2%) | 19 (10.4%) | 0.005** |
| Strabismus (%) | Orthophoria | 40 (74.0%) | 109 (86.5%) | 0.047* | 149 (82.8%) | 179 (98.4%) | < 0.001* |
| Esotropia | 5 (9.3%) | 11 (8.7%) | 16 (8.9%) | 1 (0.5%) | |||
| Exotropia | 8 (14.8%) | 6 (4.8%) | 14 (7.8%) | 2(1.1%) | |||
| Hypertropia | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | |||
| DVD | 1 (1.9%) | 0 (0.0%) | 1 (0.5%) | 0 (0.0%) | |||
| Total | 14 (26%) | 17 (13.5%) | 31 (17.2%) | 3 (1.6%) | |||
| IOOA (%) | Yes | 6 (11.1%) | 10 (7.9%) | 0.67** | 16 (8.9%) | 29 (15.9%) | 0.27** |
| Pattern (%) | V | 2 (3.7%) | 5 (3.9%) | 0.537* | 7 (3.9%) | 7 (3.8%) | 0.84* |
| A | 0 (0%) | 1 (0.8%) | 1 (0.5%) | 2 (1.1%) | |||
| Ant. seg. anomaly | Corneal abnormality | 0 (0.0%) | 1 (0.8%) | 0.507* | 1 (0.5%) | 0 (0.0%) | > 0.99* |
| Cataract | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 1 (0.5%) | |||
| Post. seg. anomaly | Macula | 4 (7.4%) | 4 (3.2%) | 0.35* | 8 (4.4%) | 4 (2.2%) | 0.45* |
| Periphery | 2 (3.7%) | 4 (3.2%) | 6 (3.3%) | 2 (1.1%) | |||
BCVA best corrected visual acuity, LogMAR logarithm minimum angle of resolution, SE spherical equivalent, D diopter, DVD dissociate vertical deviation, IO inferior oblique, SO superior oblique, MR medial rectus, SR superior rectus, LR lateral rectus, SR superior rectus, IR inferior rectus, WTR with- the- rule, ATR against- the- rule, standard deviation, Ant anterior, Post posterior, seg segment, P probability
*Based on Fisher Exact test
**Based on Chi-square
¥Based on independent T-test