Page 128 - DISINVESTMENT AND IMPLEMENTATION OF VISION SCREENING TESTS BASED ON THEIR EFFECTIVENESS

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a sufficient VA measurement at the CHC centre were classified as not amblyopic. As a consequence, very mild amblyopia could have been missed. Mild amblyopia, however, would have a much lower impact than moderate to severe amblyopia.
Another limitation of the comparison was that all children did attend their regular screening visits at the CHC centres, and that physicians may have detected more cases than physicians who were not trained to perform eye examinations: (i) the physicians were used to specific eye screening within the general health screening examination; (ii) they actively had to omit eye screening in the intervention group; (iii) they had to exclude conspicuous eye disorders and a positive family history in the intervention group, all raising their level of attention for eye disorders.
Photoscreening is not part of the vision screening programme in the Netherlands. Photoscreening is used to detect risk factors for amblyopia and is in some countries suggested as a replacement for preverbal vision screening or even VA measurements. However, it is still unclear how much amblyopia will be prevented if glasses are prescribed early. The Pediatric Eye Disease Investigator Group did not find a significant reduction in the development of strabismus, nor better stereo acuity, nor better VA when prescribing glasses at age 1-2 years to moderate hypermetropic children (+3 up to +6) compared to no prescription of glasses.14 In Flanders, Belgium, photoscreening has been introduced recently as an temporary add-on screening to VA measurements at one and two-and-a-half years of age. Implementation of photoscreening resulted in increase of prescriptions of glasses from 4.7% to 6.4%.15
The rate of failed VA measurements with the Landolt C at 45 months is currently assessed, as the VA measurements at 36 months already proved to be insufficient in 32.1% at 36 months with the APK.11 Similar rates have previously been reported for Lea Symbols and HOTV.16 Difference between VA measurement at 36 and 45 months will be further investigated as to compare the use of different VA charts, testability at different ages and diagnosis and treatment after referral. Preverbal vision screening is not only performed in the Netherlands but also in the majority of countries throughout Europe. Large differences, however, exist in type and amount of screening tests and screening personnel.1 Our results could, therefore, be informative for other countries that want to evaluate, extent, implement or disinvest their own preverbal vision screening.
In conclusion, routine eye screening tests between the age of 6-24 months can be omitted without any negative impact on amblyopia detection or its severity. Strabismus
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