- Design
- Cross-sectional paired comparison within a national cohort, randomised test order
- Population
- 995 children aged 3–15 in Shanghai (183 preschool)
- Primary outcome
- Uncorrected visual acuity and screening performance
- Effect
- Preschool referral 18.6% vs 31.2%; true positive rate 0.68 vs 0.44; specificity 0.93 vs 0.79
This cross-sectional study within a Chinese national cohort tested 995 children aged 3 to 15 with both HOTV and tumbling E logMAR charts in random order, with cycloplegic refraction and full examination as reference.
Tumbling E measured vision as worse overall (mean 0.20 vs 0.15 logMAR). The gap was about one line at age 3, more than 3 letters up to age 8, and one letter or less from age 8. Among 183 preschool children, HOTV referred fewer (18.6% vs 31.2%; difference −12.6%, 95% CI −19.2 to −5.9) while detecting more true cases (true positive rate 0.68 vs 0.44) with higher specificity (0.93 vs 0.79). In older children the charts performed similarly.
Tumbling E asks young children to judge orientation, a cognitive task that many under-8s find harder than matching letters. It is commonly used in child vision screening in India, where false referrals overload eye clinics and erode parents' trust. Switching to HOTV for children under 8 is a low-cost change these data support.
- Use HOTV letter-matching charts for vision screening in children under 8
- Keep tumbling E or letter charts for children aged 8 and over
- Train screeners in matching-card technique for HOTV
- Audit referral rates and confirmed diagnoses before and after switching
Why it matters
The chart choice in preschool screening changes both how many children are wrongly referred and how many real problems are found.
Don't overread it
The preschool comparison involved 183 children from one city, and referral thresholds may need local calibration.
The statistics, in plain English
A true positive rate of 0.68 against 0.44 means HOTV identified about two in three children with a real problem, compared with fewer than half for tumbling E. Specificity of 0.93 against 0.79 means far fewer children without problems were referred. The preschool subgroup was 183 children, so these estimates carry some imprecision.
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