Table 4.
Type of study and outcome for quantitative studies on near visual acuity in 4–7 year olds
| Reference | Type of study | Number of participants, group (and age). | Method | Outcome |
|---|---|---|---|---|
| Heller 1974 [25] | Observational |
n = 40 Group = NV Age = 2 ½–6 years |
Test: Binocular near point acuity test card Optotype spacing: 2× letter size (edge-to-edge) Distance: 33 cm Response: Verbal. |
No validation against existing charts, just determination whether 20/20 acuity was achievable with the chart. This was the case. |
| Ismail 1981 [32] | Cross sectional |
n = 4239 Group = NV Age =5.57 years (mean) |
Test: Mono- and binocular near and distance (Sheridan-Gardiner single letter test) Optotype spacing: not specified Distance: not specified. Threshold: not specified. Response: not specified. |
N5 and N6* (20/20 or 20/30) were taken as normal. Children with vision of 20/40 or lower were referred. 99.2% achieved normal vision. In the 12 children with N8 or worse low vision aids were considered. |
| Hohmann 1982 [31] | Cross sectional |
n = 62 Group = NV Age = 6–12 years |
Test: Binocular Landolt C-test Range: 0.1–1.4 (decimal acuity) Spacing: 2.6′ and 17.2′ Distance: 40 cm (and 6 m) Threshold: 88–94% Response: Verbal or matching |
The majority of subjects had vision of 1.4 (decimal). Maximum acuity uncrowded optotypes at 7 years and crowded optotypes at around 10 years. |
| Dowdeswell 1995 [23] | Cross sectional |
n = 68 Group = NV Age = 5;2–7;6 years |
Test: Monocular Bailey-Lovie chart at 0.3 and 6 m Range: 0.1–2.0 Spacing: 1× optotype size Distance: 30 cm and 6 metres Response: Not specified |
See Fig. 3. |
| Lovie-Kitchin 2001 [30] | Cross sectional |
n = 71 Group = low vision Age = 7–18 years |
Test: Binocular near text visual acuity (reading test based on the Minnesota Low Vision Reading Test) and distance visual acuity (Bailey-Lovie chart) Spacing: not specified Distance: 10 cm and 3 metres Threshold: DVA scored per letter Response: reading |
Distance vision ranged from 0.10–1.28 logMAR and near text visual acuity from 0.12–1.47 logMAR (N 1.5-N24 at 10 cm). Critical print size: 0.74–1.87 logMAR (N5-N64 at 10 cm). |
| Labib 2009 [29] | Cross sectional |
n = 50 Group = low vision Age = 5–15 years (mean age 11 ± 2.6 y) |
Test: Monocular near (Keeler’s reading chart) and distance (Landolt C) Distance: 25 cm Spacing: Not specified Response: Verbal |
The near visual acuities ranged from A10 to A20, with the mean near acuity ± SD being A13.632 ± 3.17171.DVA ranged from 4/60 (0.06) to 6/24 (0.25), with mean distance visual acuity ± SD being 0.12 ± 0.12. |
| Boonstra 2012 [21] | Non-randomized controlled trial |
n = 21 Group = low vision Age = 3 ½–6 years |
Test: Binocular LEA near chart Distance: self-chosen distance, at 40 cm and at 3 metres Spacing: 0.5 and 1.0× letter size Response: Verbal |
See Fig. 4. |
| Dekker 2012 [22] | Cross sectional |
n = 62 Group = NV Age = 4–12 years |
Test: Binocular LEA line and single at near and distance Distance: 0.3 and 3 metres Spacing: 0.5 and 1.0× letter size Response: Verbal |
Distance vision crowding ratio (95% CI): 4–6y: 1.40 (0.88–2.22) 6–12: 1.31 (0.87–1.97) Near vision crowding ratio: 4–6y: 1.01 (0.55–1.86) 6–12y: 1.01 (0.72–1.42) |
| Huurneman 2012 [27] | Cross sectional |
n = 58/n = 75 Group = low vision/NV Age = 4–8 years |
Test: Binocular C-test and LEA line at near/C-test at distance Distance: 40 cm and 5 metres (if children had acuity < 20/125 distance was reduced to 2.5 metres at distance). Spacing: C-test: 2.6 and > =30; LEA line test 0.25, 0.5 and 1.0 × letter size Threshold: 60% (3/5) Response: Verbal |
See Fig. 3. |
| Huurneman 2013 [28] | Non-randomized controlled trial |
n = 45/n = 29 Group = low vision/NV Age = 4–9 years |
Test: Binocular LEA version C-test + LEA line 50% at near; C-test Distance: 40 cm and 5 metres (viewing distance was reduced if DVA was < 20/125) Spacing: 2.6′ and ≥ 30′; 0.5× letter size Threshold: 60% (3/5) Response: Verbal |
See Figs. 3 and 4. |
| Huang 2014 [26] | Cross sectional |
n = 150 Group = NV Age = 3–5 years |
Test: Binocular near-vision chart for children 3–5 years and the Chinese standard logarithmic near vision chart Distance: 25 cm Spacing: 1× letter size Response: Verbal |
See Fig. 3. |
*N refers to size of the letters, where one point is 0.35 mm (1/72 inch). ** A1 refers to 20/20 vision at 25 cm