Mobile devices in vision screening: examination of stereovision

Amblyopia is a neurodevelopmental disorder with reduced visual acuity and impaired stereovision, therefore stereotests can be utilized to detect amblyopia and preamblyopic conditions. Our research group is developing a mobile device-based vision screening system (EuvisionTab©). The stereovision module of this application can display static and dynamic random dot stereograms. The goal of this study was to compare the performance of these tests with others. Four hundred fifty-three individuals (4-13 yrs) were included, 46 of them were amblyopic. A pediatric ophthalmological examination was performed before testing. In our stereotest, the dot density was varied to adjust the level of difficulty. Low density dynamic (1%) with noise (LDD), very low density dynamic (0.7%) without noise (VLDD), and a higher density (8%) static test (HDS) were used and compared with Lang II, TNO, StereoFly and Frisby stereotests. The predictive values and ROC analysis were calculated for each stereotest. With refractive correction, HDS, LDD, and VLDD had a sensitivity for amblyopia of 77%, 91%, and 87%, while the specificity was 89%, 71%, and 74%, respectively. The sensitivity and specificity of the Lang II, TNO, StereoFly and Frisby stereotests were: 63% and 96%, 88% and 82%, 85% and 88%, and 76% and 79%, respectively. Without refractive correction, which better resembles a real screening situation, the sensitivity of LDD and VLDD were 91% and 100%, respectively. The EuvisionTab© stereotests are slightly more sensitive for the detection of amblyopia compared to any other stereotests. LDD and VLDD have significantly higher sensitivity and lower specificity, while HDS has comparable or slightly better performance in both measures when compared to other stereotests. Our stereotests may become part of the state-of-the-art vision screening protocol, because of advantages such as cloud-based data storage, flexible parameter settings and randomized image sequence.