Abstract
BACKGROUND/AIMS—Single optotype tests of visual acuity are widely used for preschool vision screening in order to optimise cooperation with testing. These tests may, however, underestimate the visual acuity deficit in amblyopia because they lack visual crowding. This study assessed the resultant negative predictive value (NPV) for amblyopia. METHODS—Cohort study of 936 children in the Cambridge Health District selected by date of birth. The presence of amblyopia among children who had passed preschool vision screening was determined using Snellen line acuity as the reference test. Preschool vision screening was conducted at 3.5 years of age by community orthoptists. The screening assessment comprised Sheridan-Gardiner single optotype test of visual acuity (referral criterion 6/9 or worse in either eye), cover test, ocular movements, 20 prism test, and TNO stereotest. RESULTS—The overall NPV of preschool vision screening for amblyopia was 100% (95% CI 99.4% to 100%). Most children with amblyopia were detected by the Sheridan-Gardiner single optotype test of visual acuity, but the other screening tests were necessary to prevent any false negatives. In isolation, the Sheridan-Gardiner single optotype test of visual acuity has a NPV for amblyopia of only 99.6% (95% CI 98.7% to 99.9%). CONCLUSION—Preschool vision screening using a single optotype test of visual acuity does achieve a high NPV for amblyopia, but only under certain conditions. These comprise a low threshold for referral (6/9 or worse in either eye) and the inclusion of a cover test and tests of binocular function in the screening assessment.
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Selected References
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- Allen J. W., Bose B. An audit of preschool vision screening. Arch Dis Child. 1992 Oct;67(10):1292–1293. doi: 10.1136/adc.67.10.1292. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bolger P. G., Stewart-Brown S. L., Newcombe E., Starbuck A. Vision screening in preschool children: comparison of orthoptists and clinical medical officers as primary screeners. BMJ. 1991 Nov 23;303(6813):1291–1294. doi: 10.1136/bmj.303.6813.1291. [DOI] [PMC free article] [PubMed] [Google Scholar]
- De Becker I., MacPherson H. J., LaRoche G. R., Braunstein J., Cottle R., McIntyre L. L., Kozousek V. Negative predictive value of a population-based preschool vision screening program. Ophthalmology. 1992 Jun;99(6):998–1003. doi: 10.1016/s0161-6420(92)31865-2. [DOI] [PubMed] [Google Scholar]
- Egan D. F., Brown R. Vision testing of young children in the age range 18 months to 4 1/2 years. Child Care Health Dev. 1984 Nov-Dec;10(6):381–390. doi: 10.1111/j.1365-2214.1984.tb00194.x. [DOI] [PubMed] [Google Scholar]
- Hilton A. F., Stanley J. C. Pitfalls in testing children's vision by the Sheridan Gardiner single optotype method. Br J Ophthalmol. 1972 Feb;56(2):135–139. doi: 10.1136/bjo.56.2.135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ingram R. M., Holland W. W., Walker C., Wilson J. M., Arnold P. E., Dally S. Screening for visual defects in preschoolchildren. Br J Ophthalmol. 1986 Jan;70(1):16–21. doi: 10.1136/bjo.70.1.16. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ingram R. M. Review of children referred from the school vision screening programme in Kettering during 1976-8. BMJ. 1989 Apr 8;298(6678):935–936. doi: 10.1136/bmj.298.6678.935. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Köhler L., Stigmar G. Vision screening of four-year-old children. Acta Paediatr Scand. 1973 Jan;62(1):17–27. doi: 10.1111/j.1651-2227.1973.tb08060.x. [DOI] [PubMed] [Google Scholar]
- Köhler L., Stigmar G. Visual disorders in 7-year-old children with and without previous vision screening. Acta Paediatr Scand. 1978 May;67(3):373–377. doi: 10.1111/j.1651-2227.1978.tb16337.x. [DOI] [PubMed] [Google Scholar]
- McGraw P. V., Winn B. Measurement of letter acuity in preschool children. Ophthalmic Physiol Opt. 1995 Mar;15 (Suppl 1):S11–S17. [PubMed] [Google Scholar]
- Newman D. K., Hitchcock A., McCarthy H., Keast-Butler J., Moore A. T. Preschool vision screening: outcome of children referred to the hospital eye service. Br J Ophthalmol. 1996 Dec;80(12):1077–1082. doi: 10.1136/bjo.80.12.1077. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rahi J. S., Dezateux C. The future of preschool vision screening services in Britain. BMJ. 1997 Nov 15;315(7118):1247–1248. doi: 10.1136/bmj.315.7118.1247. [DOI] [PMC free article] [PubMed] [Google Scholar]
- STUART J. A., BURIAN H. M. A study of separation difficulty. Its relationship to visual acuity in normal and amblyopic eyes. Am J Ophthalmol. 1962 Mar;53:471–477. [PubMed] [Google Scholar]
- Salt A. T., Sonksen P. M., Wade A., Jayatunga R. The maturation of linear acuity and compliance with the Sonksen-Silver Acuity System in young children. Dev Med Child Neurol. 1995 Jun;37(6):505–514. doi: 10.1111/j.1469-8749.1995.tb12038.x. [DOI] [PubMed] [Google Scholar]
- Simmers A. J., Gray L. S., Spowart K. Screening for amblyopia: a comparison of paediatric letter tests. Br J Ophthalmol. 1997 Jun;81(6):465–469. doi: 10.1136/bjo.81.6.465. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Simons K. Visual acuity norms in young children. Surv Ophthalmol. 1983 Sep-Oct;28(2):84–92. doi: 10.1016/0039-6257(83)90076-0. [DOI] [PubMed] [Google Scholar]
- Williamson T. H., Andrews R., Dutton G. N., Murray G., Graham N. Assessment of an inner city visual screening programme for preschool children. Br J Ophthalmol. 1995 Dec;79(12):1068–1073. doi: 10.1136/bjo.79.12.1068. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wormald R. P. Preschool vision screening in Cornwall: performance indicators of community orthoptists. Arch Dis Child. 1991 Aug;66(8):917–920. doi: 10.1136/adc.66.8.917. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yang Y. F., Cole M. D. Visual acuity testing in schools: what needs to be done. BMJ. 1996 Oct 26;313(7064):1053–1053. doi: 10.1136/bmj.313.7064.1053. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Youngson R. M. Anomaly in visual acuity testing in children. Br J Ophthalmol. 1975 Mar;59(3):168–170. doi: 10.1136/bjo.59.3.168. [DOI] [PMC free article] [PubMed] [Google Scholar]