Do the near computerised and non-computerised crowded Kay picture tests produce the same measure of visual acuity?

Aims: Apps have been developed to assess visual acuity (VA) on tablet computers. The aim of this study was to compare near VA scores using crowded Kay pictures on the iSight app and the printed crowded Kay picture test in amblyopic and typically developing children to determine whether the tests are clinically interchangeable.

Methods: Fifty-seven participants (34 typically developing and 23 amblyopic children) aged 3–9 years had their uniocular near VA measured using computerised crowded Kay pictures on the iSight app for the iPad and the printed near crowded Kay picture test. Data were analysed to determine whether there was a significant difference between the two tests. Bland–Altman plots were constructed to assess how well the tests agreed with each other.

Results: There was no significant difference between the two tests in all test conditions with the exception of the left eyes of typically developing children measured using the per line termination criteria ( p = 0.01). Bland–Altman analysis showed good agreement between the iSight app and near crowded Kay picture test.

Conclusions: The results of the study indicate that near Kay pictures on the iSight app are clinically interchangeable with the traditional printed Kay pictures. These results compare well with other published studies comparing computerised vision tests with their traditional counterparts.