To begin the visual acuity assessment, present the initial grading on the computer depending on the child's age and as per the Teller Acuity Cards Two or TAC Two Test present the initial grading ranging from 0.33 to 30.0 cycles per degree in one by two octave steps for 1000 milliseconds, which is the length of a trial before presenting a blank screen for 200 milliseconds. Present the same stimulus again, followed by a blank screen. Present the grading of the same spatial frequency set three times.
During the execution of the procedure, let the webcam record the facial pictures for analyzing the child's watching behavior. The vision testing program checks the eye movement responses with the criteria to determine whether the stimulus has been seen. Let the testing result processing program present the subsequent stimulus according to the protocol.
After every three trials, present a GIF image with background music as a visual reward to maintain the child's interest. Stop the test if no gaze data are usable due to the child turning around or closing their eyes within one minute of the GIF image presentation. Once the test is complete, analyze the grading acuity results for the child outputted by the software programs.
The AACP was applied to a group of 155 normally developing infants and toddlers from five to 36 months old. The grading acuity measured by the AACP gradually increased with the infant's age. In infants of six to 12 months, the grading acuity increased by 0.5 octaves.
The grading acuity was increased by one octave in the age group, 12 to 24 months. An increase of 1.5 octaves was observed in toddlers of 24 to 36 months. The trend of acuity development in this study was consistent with the acuity development measured by TAC Two in the same group of infants.
