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

Summary

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

Abstract

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.

Introduction

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'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 t....

Protocol

The protocol described here was approved by the Ethical Committee of Peking University First Hospital (PKUFH 2018-223). The procedures adhered to the tenets of the Declaration of Helsinki for research involving human subjects. The study format was described, and informed consent was obtained from the parents of the participants.

1. Preparation of the apparatus

NOTE: The AACP components were set up in a mildly illuminated test room. Drapes were pulled in the room to avoid interference from sunlight. A display system, a recording system, and an analysis system were the three components of the AACP (<....

Results

The AACP was applied to one group of children¹¹: 155 normally developing infants and toddlers (5 to 36 months old, based on gestational age). In a previously published study, the grating acuity results obtained by the AACP were compared with those obtained by TACII. The results obtained by these two procedures are significantly correlated (r₁₅₃ = 0.83, p < 0.001). Only 10.32% (16 of 155) of the children's results differed by more than one octave. Among them, eight children w.......

Discussion

Several studies^7,8,9,10 based on the eye-tracking method have shown the value of this method in evaluating infants and young children who have difficulty in verbal communication. However, the number of participants in previous studies is relatively small. Only 30 infants under 12 months of age were tested by the ACTIVE procedure, which was developed by Jones et al.⁷. The.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
AACP procedure software	In-house	In-house	The AACP procedure software (China National Invention Patents, No. 201910865074.4 and No. 201510919621.4) comprises a stimulus displaying module, a vision testing module, and a testing result processing module.
Computer processor	Intel Corporation, Santa Clara, CA, USA	Intel CORE i7-6500U processor	Analysis system
Display monitor	InnoLux Co., Ltd., China	InnoLux M280DGJ-L30	Display system
Webcam	Logitech International S.A., Lausanne, Switzerland	Logitech C920 high-definition pro webcam	Recording system