The Dyop® Children’s Test and Infant Test are ways of rapidly and easily determining visual acuity in infants for binocular and monocular testing.
The Dyop® Children’s Test has TWO peripheral Dyops, of which only one is spinning, and where the location of that spinning Dyop alternates from one peripheral side of the monitor to the other.
The Dyop® Infant Test has ONE peripheral spinning Dyop where the location of that spinning Dyop alternates from one peripheral side of the monitor to the other.
The methodology is based on preferential looking. Infants, children, and most adults will instinctively turn their head to track the location of a peripherally spinning Dyop.
The location of that rotating peripheral spinning Dyop alternates as the Dyop size gets bigger or smaller. The test administrator should be able to easily determine if the child or infant is still observing the location of that spinning Dyop since a children and infants will exhibit this tracking behavior pattern while the Dyop is still big enough for them to detect the Dyop rotation.
When the Dyop gaps (and segments) become too small to detect the Dyop rotation (at a sub-acuity diameter), the conditioned response for the subject will be to rapidly exhibit alternating head and eye motion looking for that formerly rotating Dyop.
The acuity end point can be verified by incrementally increasing the Dyop diameter to the smallest diameter where Dyop rotation is again detected.
To double check your findings, either incrementally reduce the Dyop to that sub-acuity diameter or to move the child away from the monitor to see if their behavior changes when they are further away from the previously determined acuity end point.
The administrator can also pause the rotating Dyop without changing the size for ease in testing the end point for false positives.
The Dyop Children’s and Infant acuity tests also allow their acuity measurement to be correlated to Adult acuity.