Table 1 Characteristics of comitant exotropia (XT).
| Convergence weakness (CW) | Divergence excess (DE) | Basic (B) | p | Idiopathic XT | Secondary XT | p | |
|---|---|---|---|---|---|---|---|
| Number (% of all XT) | 51 (10%) | 270 (55%) | 132 (27%) | 20 (4%) | 19 (4%) | ||
| Age of presentation, yr (SD) (range) | 6.8 (2.8) (0.1–15.0) | 5.4 (3.0) (0.2–15.1) | 5.6 (3.0) (0.1–15.2) | <0.01 for CW/DE, CW/B | 7.1 (3.9) (0.3–14) | 5.5 (3.6) (0.3–14.8) | 0.19 |
| Estimated age of onset | |||||||
| 0 to 2 years | 4 (7%) | 89 (33%) | 33 (25%) | 6 (27%) | 9 (47%) | ||
| 3 to 5 years | 29 (58%) | 112 (41%) | 61 (46%) | 4 (23%) | 3 (19%) | ||
| 6 to 12 years | 17 (32%) | 68 (25%) | 38 (28%) | 10 (50%) | 7 (34%) | 0.37 | |
| 13 to 16 years | 1 (2%) | 1 (0%) | 0 (0%) | <0.01 | — | — | |
| Distant strabismus (PD)* (SD) (range) | 14.9 (10.2) (0–57) | 29.0 (11.2) (2–66) | 27.6 (11.8) (0–60) | <0.001 for CW/DE, CW/B | 37.3 (14.4) (8–65) | 31.4 (12.0) (8–55) | 0.15 |
| Near strabismus (PD)* (SD) (range) | 26.1 (12.8) (6–87) | 14.0 (10.7) (0–55) | 26.7 (11.3) (2–60) | <0.001 for CW/DE, DE/B | 37.5 (11.2) (10–63) | 29.3 (12.8) (6–45) | 0.04 |
| Presence of | NA | NA | NA | ||||
| Distant stereoacuity | 10/25 (40%) | 53/112 (53%) | 29/59 (50%) | 0.51 | |||
| Near stereoacuity | 43/47 (94%) | 202/216 (94%) | 97/107 (90%) | 0.47 | |||
| Spherical equivalent (D) (SD) | −2.4 (3.6) | −0.5 (2.4) | −0.6 (2.2) | <0.001 for CW/DE, CW/B | 0.3 (2.5) | −1.4 (4.0) | 0.14 |
| Anisometropia ⩾1 D | 8/45 (18%) | 39/226 (17%) | 22/106 (21%) | 0.75 | 6/17 (35%) | 11/16 (68%) | 0.05 |
| Astigmatism ⩾1.5 D | 22/45 (50%) | 53/226 (23%) | 27/106 (25%) | <0.001 | 6/17 (35%) | 10/16 (62%) | 0.11 |
| Amblyopia/ preference | 12 (23%) | 55 (20%) | 21 (16%) | 0.14 | 6 (30%) | 10 (52%) | <0.01 |
| A/V pattern or DVD | 12 (23%) | 84 (31%) | 46 (35%) | 0.20 | 11 (55%) | 3(16%) | <0.01 |
*Measurement taken from first formal orthoptic assessment (usually during first or second visit). If spectacles were prescribed during these visits, the measurement performed after at least 6 weeks of spectacle wear was taken.