Table 4.
Percentages of bilateral and unilateral visual impairment in participants with one or both eyes with axial length <21 mm (n=96) compared with all EPIC-Norfolk participants with no eye of axial length <21 mm (n=7920) by Fisher's exact test
| LogMAR | Snellen equivalent | Classification | EPIC-Norfolk participants without small eyes (n=7920 total) | EPIC-Norfolk participants with small eyes (n=96 total) |
p Value | ||
|---|---|---|---|---|---|---|---|
| n | Prevalence (95% CI) | n | Prevalence (95% CI) | ||||
| >1.30 better eye | <3/60; 20/400 | WHO blindness | 2 | 0.03% (0.00, 0.06) | 1 | 1.0% (0.0, 3.1) | 0.036 |
| >0.48 better eye | <6/18; 20/60 | Blindness and visual impairment; ‘low vision’ | 45 | 0.6% (0.4, 0.7) | 2 | 2.1% (0.0, 5.0) | 0.11 |
| >0.22 better eye | <6/10; 20/32 | UK driving standard | 422 | 5.3% (4.8, 5.8) | 7 | 7.29% (2.0, 12.56) | 0.36 |
| >0.30 better eye | <6/12; 20/40 | Previous visual impairment studies, American driving standard | 259 | 3.3% (2.9, 3.7) | 5 | 5.2% (0.7, 9.7) | 0.25 |
| >1.0 worse eye | <6/60; 20/200 | Unilateral visual impairment | 120 | 1.5% (1.3, 1.8) | 11 | 11.5% (5.0, 18.0) | <0.001 |
| >0.48 worse eye | <6/18; 20/60 | Unilateral visual impairment | 470 | 5.9% (5.4, 6.5) | 24 | 25.0% (16.2, 33.8) | <0.001 |
| >0.30 worse eye | <6/12; 20/40 | Unilateral visual impairment | 1341 | 16.9% (16.1, 17.8) | 29 | 30.2% (20.9, 39.6) | 0.001 |
Bilateral visual impairment is defined as both eyes with a visual acuity less than the respective value and unilateral visual impairment as one eye with a visual acuity less than the respective value.
EPIC, European Prospective Investigation of Cancer.