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Vision screening at 8 and 18 months. Steering Committee of Oxford Region Child Development Project
A Johnson1, M Stayte, C Wortham
1Oxford Region Child Development Project, Maternity Department, John Radcliffe Hospital.
Insights
Community screening for infant vision defects is ineffective in high-risk groups. Most cases are found in low-risk infants, indicating a need to re-evaluate screening strategies for ocular and vision defects.
Area of Science:
- Ophthalmology
- Public Health
- Pediatrics
Background:
- Infant ocular and vision defects require early detection.
- Community-based screening programs aim to identify these defects in at-risk infants.
Purpose of the Study:
- To evaluate the effectiveness of an existing community screening program for ocular and vision defects in high-risk infants.
Main Methods:
- Infants at high risk (born 1984, specific birth criteria) and a low-risk population were identified.
- Routine screening tests were applied by health visitors at 8 and 18 months to high-risk infants.
- Screening results were compared with defects detected by age 2.
Main Results:
- Current screening tests were insensitive and had low positive predictive value in high-risk infants.
- 85% of all detected cases by age 2 were in the low-risk population.
- Referral patterns and age at referral differed between high-risk and low-risk groups.
Conclusions:
- Community screening of high-risk infant populations offers limited value for detecting vision and ocular defects.
- Screening efforts should also target low-risk populations due to their higher contribution to detected cases and different referral patterns.
Objective:
To determine the effectiveness of an existing screening programme based in the community for ocular and vision defects in infants considered at increased risk of such defects.
Design:
Children with ocular or vision defect by the age of 2 were ascertained by searching records. Those from populations at high risk were matched with their results from screening tests. The characteristics of the cases among this population were compared with those of the cases in the remainder of the population. Patterns of referral and age at referral were studied in both groups.
Setting:
The study was conducted within Oxfordshire Health District.
Subjects:
433 Children at high risk born in 1984 to mothers living in the health district at delivery and who either weighed less than 2000 g or weighed 2000 g and over and required admission to a special care nursery for longer than 24 hours. The low risk population (6254) were infants without these characteristics who were resident in the health district at the time of referral.
Interventions:
Screening tests for vision or ocular defects already routinely used were applied by health visitors at 8 and 18 months to the children at high risk.
Main Outcome Measure:
Comparison of results of screening tests with vision and ocular defects detected by the age of 2.
Results:
Screening tests in current use for vision loss and squint in this age group were insensitive and had a low positive predictive value when applied to a high risk population. Defects that were not apparent on direct inspection were unlikely to be detected by these tests. In the high risk group the relative risk of having a defect was 2.8 (95% confidence interval 1.8 to 4.5) but 85% of all cases detected by the age of 2 were in children at low risk. Referral patterns and age of referral differed in the two groups.
Conclusions:
Screening by health visitors of high risk populations contributes little to the detection of vision and ocular defects. This type of evaluation needs to be applied also to low risk populations, who have different referral patterns and contribute most of the cases.