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M M East

Publications and source records attributed to M M East.

2 recordsLinked to original sources
PubMed2000

Prevalence of amblyopia among defaulters of preschool vision screening.

The prevalence of amblyopia among screening defaulters is an important determinant of the efficacy of amblyopia detection by preschool vision screening. A retrospective cohort study was therefore performed to assess an orthoptist-based preschool vision screening programme. The preschool vision screening status of children in the cohort was determined by reviewing their Community Child Health records. The prevalence of amblyopia among screening defaulters was determined by reviewing each child's school entry vision test (performed at 5.5 years of age), with retesting if a Snellen line acuity of 6/6 in each eye had not been documented. For comparison, the prevalence of amblyopia among screening attenders was also determined. The preschool vision screening status was known for 86.0% (772/898) of the cohort. The attendance rate at preschool vision screening was 79.2%. The prevalence of amblyopia among screening defaulters was 1.3% (95% CI 0.2% to 4.5%). The prevalence of amblyopia among screening attenders was 2.5% (95% CI 1.4% to 4.1%). There was no significant difference in the prevalence of amblyopia between screening defaulters and screening attenders (P=0.53). The efficacy of amblyopia detection by preschool vision screening is therefore highly dependent on its attendance rate. Preschool vision screening programmes with a low attendance rate will fail to detect a significant proportion of children with amblyopia.

Amblyopia↗
PubMed1999

Preschool vision screening: negative predictive value for amblyopia.

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(Delta) 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.

Amblyopia↗