ASTEROID: A New Clinical Stereotest on an Autostereo 3D Tablet

Purpose: To describe a new stereotest in the form of a game on an autostereoscopic
tablet computer designed to be suitable for use in the eye clinic and present data on
its reliability and the distribution of stereo thresholds in adults.
Methods: Test stimuli were four dynamic random-dot stereograms, one of which
contained a disparate target. Feedback was given after each trial presentation. A
Bayesian adaptive staircase adjusted target disparity. Threshold was estimated from the
mean of the posterior distribution after 20 responses. Viewing distance was monitored
via a forehead sticker viewed by the tablet’s front camera, and screen parallax was
adjusted dynamically so as to achieve the desired retinal disparity.
Results: The tablet must be viewed at a distance of greater than ~35 cm to produce a
good depth percept. Log thresholds were roughly normally distributed with a mean
of 1.75 log10 arcsec ¼ 56 arcsec and SD of 0.34 log10 arcsec ¼ a factor of 2.2. The
standard deviation agrees with previous studies, but ASTEROID thresholds are
approximately 1.5 times higher than a similar stereotest on stereoscopic 3D TV or on
Randot Preschool stereotests. Pearson correlation between successive tests in same
observer was 0.80. Bland-Altman 95% limits of reliability were 60.64 log10 arcsec ¼ a
factor of 4.3, corresponding to an SD of 0.32 log10 arcsec on individual threshold
estimates. This is similar to other stereotests and close to the statistical limit for 20
Conclusions: ASTEROID is reliable, easy, and portable and thus well-suited for clinical
stereoacuity measurements.
Translational Relevance: New 3D digital technology means that research-quality
psychophysical measurement of stereoacuity is now feasible in the clinic.
File Size1.9 MiB
DateMarch 11, 2019
AuthorVancleef K, Serrano-Pedraza I, Sharp C, Slack G, Black C, Casanova T, Hugill J, Rafiq S, Burridge J, Puyat V, Ewane Enongue J, Gale H, Akotei H, Collier Z, Haggerty H, Smart K, Powell C, Taylor K, Clarke MP, Morgan G, Read JCA