Page 96 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

CHAPTER 5
Outcome measures and Statistical Analysis
The primary outcome measure was the number of referred children and the number of diagnosed amblyopia cases in both groups.
All data were entered into an Excel file and SPSS database. Statistical analysis was performed with the statistical package SPSS version 20.0 (for Windows IBM Corp., Armonk, NY, USA). Descriptive statistics were used. The questionnaires frequencies were analysed.
RESULTS
Inclusion
All children born in the area of, and registered at, the participation CHC’s were included at baseline.
Screened group
The screened group comprised a total of 6188 children. No data were available for 129 children (dropouts) because they had either moved out of the area, had no screening record or were non-users of the CHC (e.g. treated for other disorders or because of religious reasons). Another 28 children did not visit the CHC at 6-9 months, but underwent screening before and after this timeframe. 524 children visited the CHC, but the physician did not specifically screen the eyes in these cases, because of, in many cases, other priorities of the child. These children were not regarded as dropouts, based on intention-to-treat principle (Table 1).
Unscreened group
The unscreened group comprised a total of 5623 children. No data were available for 141 children (dropouts). Another 27 children did not visit the CHC at 6-9 months, but underwent screening before and after this timeframe. In case of 434 children in the unscreened group, screening was performed, mostly because of predetermined study criteria: observed eye disorders or positive family history. Some were, however, screened erroneously out of routine or per accident. In 1596 children it remained inconclusive whether eye screening had indeed not been performed. In these cases, only a box was ticked in the electronic screening record without further specifications, indicating that there were no abnormalities found or that screening had not been performed. However, eighteen of 26 physicians declared, when asked by phone interview, that they had adhered to the protocol and not performed the screening when they had ticked the box (Table 1).
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