Name: Eye-Tracking Calibration for Automated Visual Acuity Assessment
Uploaded: 2023-03-17T13:30:00
Description: Watch this Scientific Journal Video about Eye-Tracking Calibration for Automated Visual Acuity Assessment at JoVE.com

The video outlines a procedure for testing a child's eye tracking using a calibration system. It details obtaining parental consent, positioning the child correctly, ensuring visibility for the webcam, and utilizing software to analyze the child's gaze focus on displayed images, initiating the test automatically once detected.

eye-tracking calibration for automated visual acuity assessment

An Automated Assessment of Visual Acuity in Infants and Toddlers

The infantile period is a critical period for visual development. Visual problems that arise early in life can have a significant impact on a child&#39;s development. It is important to be able to perform a quantitative visual assessment in infants, which can help detect early vision problems. However, because infants are not cognitively developed or expressive enough to recognize visual acuity chart symbols, such as letters or graphs, measuring their visual acuity is difficult. The current gold standard for infant vision assessment is the acuity card procedure1 based on the preferential looking test2. However, because this method requires experienced testers to judge visual acuity by observing the child&#39;s eye movements3,4,5,6, it is limited by the experience of the testers4,5. Therefore, acuity card procedures, such as Teller Acuity Cards (TACs)5,6, remain a subjective method. Thus, there is a need for a method that can quantitatively measure visual acuity in infants and young children, that can be used without the need for verbal communication and that is not limited by requiring experienced testers.
The invention and use of the remote eye tracker enabled an automated acuity measuring system to be developed. In previous studies, eye-tracking methods have been used as a tool for visual function evaluation in children7,8,9,10. A remote eye tracker can be used for gaze tracking and is a substitute for a tester&#39;s observation of a child&#39;s eye movements. The ACTIVE procedure7 and AVAT procedure10 are fully automated visual acuity tests with a remote eye tracker; they have yielded comparable visual acuity results to the Keeler Acuity Cards test in healthy infants and young children. As opposed to other recent studies, we used a webcam instead of a remote eye tracker to capture the child&#39;s gaze. We invented an eye movement data automatic acquisition method based on computer vision. The procedure combined the eye movement acquisition method with the preferential looking technique in assessing visual function in children.
This paper aims to present a novel automated method, which can evaluate visual acuity in young children, called the automated acuity card procedure (AACP). This procedure is particularly useful for infants and younger children who have not yet acquired sufficient communication skills. The key aspect is that visual responses can be quantitated to yield grating acuity in infants and young children. Grating acuity measurement enables the detection of visual pathologies and plays an important role in subsequent medical management.

Author Spotlight: An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System  

An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System

This novel automated method called the Automated Acuity Card Procedure, or AACP, can evaluate visual acuity in young children. The procedure is useful for infancy and the younger children who have not yet acquired sufficient communication skills. The AACP procedure uses a webcam instead of a remote eye-tracker.A two-choice preferential-looking test automatically recognizes the child's watching behaviors. When the child watch the visual stimuli on a digital display screen, cartoon images are presented in the center of the screen as visual rewards during the testing procedure. It reduces the misstatement of the procedure caused by the infant's eye gets shifting to the side In the future, by changing the types of visual stimulation, the AACP may be used to evaluate other visual information processing functions early in children's development.

Watch this Scientific Journal Video about Eye-Tracking Calibration for Automated Visual Acuity Assessment at JoVE.com

Eye-Tracking Calibration for Automated Visual Acuity Assessment  

Begin by obtaining informed consent from the parents of the child to be tested with an eye tracking calibration system and describe the study format to them. Position the child to be tested at 55 centimeters from the display monitor in the parent's lap. Adjust the position of the lifting table to place it with the monitor so that the screen is perpendicular to the child's eyes.Adjust the webcam's position to ensure that the child's face is visible in the recording system and to avoid capturing faces other than the child's. Before starting the procedure inform the child that they will watch the screen. Instruct the parent to prompt the child to look at the screen when the child is not paying attention.Then open the automated acuity card procedure or AACP software and type the child's information including name, sex, and age into the software. Click on the start button to calibrate the procedure. A graphics interchange format, or GIF image appears against a white background in the center of the screen for at least three seconds.The analysis system simultaneously determines whether the child's line of sight is fixated on the image by showing green dot on the screen. If the gaze data is not available within a minute, the screen presents another cartoon GIF image. When gaze coordinates are detected within this region, the test procedure starts without the tester's action and runs automatically.

eye-tracking-calibration-for-automated-visual-acuity-assessment

Research

JoVE Journal

Behavior

Visual acuity measurement is an important visual function test to perform in infancy and childhood. However, accurate visual acuity measurement in infants is difficult because of deficiencies in their communication ability. This paper presents a novel automated method to assess visual acuity in children (5-36 months old). This method, the automated acuity card procedure (AACP), uses a webcam for eye tracking and recognizes children's watching behaviors automatically. A two-choice preferential-looking test is performed when the tested child watches the visual stimuli shown on a high-resolution digital display screen. When the tested child watches the stimuli, their facial pictures are recorded by the webcam. These pictures are used by the set computer program to analyze their watching behavior. With this procedure, the child's eye movement responses to different stimuli are measured, and their visual acuity is assessed without communication. By comparing the results with grating acuity obtained by Teller Acuity Cards (TACs), AACP performance is deemed comparable to that of TACs.

In this paper, we present a novel automated method for assessing visual acuity in infants and toddlers by using an eye-tracking system.

Visual acuity measurement is an important visual function test to perform in infancy and childhood. However, accurate visual acuity measurement in infants ...

The Automated Testing Procedure for Visual Acuity Assessment

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.