8th March 2019, Volume 132 Number 1491

William Muller, Logan Mitchell, Graham Wilson

Amblyopia, or ‘lazy eye’, is the most common ophthalmological condition affecting children, with a prevalence of approximately 1–5%.1–3 It arises from abnormal visual development during childhood, a process occurring competitively…

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Summary

This study reviewed the results of the four-year-old vision screening programme (B4 School Check) in Southern and Tairawhiti DHBs over a six-month period in 2016. Of the 2,109 children screened, 176 (8.3%) ‘failed’ the vision test and were referred on to either optometrist or DHB ophthalmology clinic. Only 91 (51.7%) were determined to have been seen as a result of that referral, and of them 39 (42.8%) were found to have normal vision. Of those referred and seen with abnormal vision, the vast majority (>92%) needed glasses for simple refractive error, while only 10% required any treatment other than glasses. Concerningly, 48.3% of children referred from the B4SC vision screening pro-gramme were not able to be confirmed as having received optometric or ophthalmic review as a con-sequence of that referral.

Abstract

Aim

To assess the accuracy of the B4 School Check (B4SC) vision screening programme in two distinct regions of New Zealand.

Method

A retrospective audit of all children who were screened for vision in the Southern and Tairawhiti District Health Boards, between 1 April and 30 September 2016. Results from the B4SC screening programme (n=2,109) were compared to records for all children who were screened and subsequently presented to an optometrist at a DHB eye clinic (n=116).

Results

The B4SC produced a sensitivity in the range of 54.7% to 94.7% and a specificity of 93.8% to 95.7%. There was a low positive predictive value (PPV), between 29.5% and 51.1%, with a relatively high number of false positive referrals. The negative predictive value (NPV) was higher, however, between 97.8% and 99.7%, meaning nearly all children who passed screening had no visual impairment.

Conclusion

The high NPV is reassuring that very few children with visual impairment are missed by screening. The low PPV was consistent with the international literature and is related to a tendency for over-referral from the B4CS programme. Further work could evaluate increasing the threshold for referral to reduce the number of false positive cases.

Author Information

William Muller, Department of Medicine, University of Otago, Dunedin School of Medicine, Dunedin; Logan Mitchell, Consultant Ophthalmologist, Dunedin Hospital, Clinical Senior Lecturer, University of Otago, Dunedin School of Medicine, Dunedin; Graham Wilson, Ophthalmologist, Gisborne Hospital, Clinical Senior Lecturer, University of Otago, Gisborne.

Acknowledgements

The authors would like to thank The Maurice and Phyllis Paykel Trust for providing scholarship to William Muller to help fund this study. The authors would also like to thank Pat Tuohy and the Ministry of Health for providing help with the study design and data collection. Prof Nick Wilson provided helpful comments in the manuscript. 

Correspondence

Dr Logan Mitchell, Consultant Ophthalmologist, Dunedin Hospital, Clinical Senior Lecturer, University of Otago, Dunedin School of Medicine, Dunedin.

Correspondence Email

logan.mitchell@otago.ac.nz

Competing Interests

Nil.

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