Page 65 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

The effect of omitting an early population-based vision screen in the Netherlands: A micro-simulation model approach
The sensitivity of the total programme is different from the sensitivity per screen. If all the separate screens are combined into one programme, this will give a higher overall sensitivity. The sensitivity curves presented here are estimated per screen per amblyopia type (Figure 3).
For each amblyopia type, the mean actual sensitivity per screen was calculated. The sensitivity of the preverbal screens was less than 15% per screen. The sensitivity of the VA screens was 17–26% per screen. Using the incidence curves and the mean sensitivity per screen, we estimated the effect per screen.
The Monte Carlo simulation that best approached the observational data was used to estimate the effect of each screen. Using the estimates for mean incidence and mean sensitivity, we determined the cumulative detection over the subsequent screens per amblyopia type. From 2964 children, 59 amblyopia cases were detected by screening by the age of 5 years (Figure 4). For a screening programme with omission of the 24-month screen, more children were detected at the screens at age 3 years and later. The number of detected cases of amblyopia at age 5 would be reduced by 3.4% (57 vs. 59 cases) (Figure 4).
Figure 3. The estimated test sensitivity per screen per amblyopia type for the six screening examinations.
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