Table 1. Baseline characteristics of study population at age 3 years by ever presence amblyopia and/or strabismus status.
| Covariate | Category | No eye condition, n = 13,431 (weighted %) | Strabismus alone, n = 264 (weighted %) | Refractive amblyopia, n = 188 (weighted %) | Strabismic or mixed amblyopia, n = 84 (weighted %) | χ2 global (weighted) p-value |
|---|---|---|---|---|---|---|
| Sex | Girls | 6568 (49%) | 131 (49%) | 95 (51%) | 34 (42%) | 0.65 |
| Boys | 6863 (51%) | 133 (51%) | 93 (49%) | 50 (58%) | ||
| Ethnicity | White | 11535 (89%) | 240 (94%) | 172 (95%) | 77 (92%) | <0.01 |
| Non-white | 1896 (11%) | 24 (6%) | 16 (5%) | 7 (8%) | ||
| Birth order | 1 | 6814 (51%) | 155 (61%) | 102 (54%) | 45 (55%) | 0.10 |
| 2 | 4056 (31%) | 67 (27%) | 46 (26%) | 24 (25%) | ||
| 3+ | 2561 (18%) | 42 (12%) | 40 (20%) | 15 (20%) | ||
| Gestational age | ≥37 weeks | 12,565 (94%) | 230 (84%) | 173 (91%) | 74 (91%) | <0.01 |
| <37 weeks | 866 (6%) | 34 (16%) | 15 (9%) | 10 (9%) | ||
| Maternal education | A-levels or higher | 4876 (37%) | 78 (33%) | 63 (33%) | 21 (27%) | 0.30 |
| O-levels | 6265 (48%) | 131 (49%) | 87 (47%) | 42 (55%) | ||
| None | 2290 (15%) | 55 (18%) | 38 (21%) | 21 (18%) | ||
| Household language | English | 12989 (94%) | a | a | a | NA |
| Non-English | 422 (6%) | a | a | a | ||
| Household income | ≥£20800 | 4858 (39%) | 72 (31%) | 57 (32%) | 17 (25%) | 0.02 |
| £10400-£20800 | 4392 (32%) | 89 (32%) | 61 (33%) | 32 (40%) | ||
| <£10400 | 4181 (29%) | 103 (37%) | 70 (36%) | 35 (35%) | ||
| Total | Proportion (95%CI) | 95.9% (95.5–96.3) | 1.9% (1.6–2.2) | 1.5% (1.3–1.8) | 0.7% (0.6–0.9) |
a Not provided to avoid potential disclosure.