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Updated: Dec 10, 2025
Author Spotlight: An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System
Published on: March 17, 2023
Utilization of Visual Acuity Retroilluminated Charts for the Assessment of Afferent Visual System Dysfunction in a
Peter V Sguigna1, Morgan C McCreary, Darrel L Conger
1Multiple Sclerosis Division (PVS, MM, DC, BMG), Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, Texas; Department of Neurology (JG), University of California San Diego, San Diego, California; Department of Neurology and Pediatrics (LB), Boston Children's Hospital, Boston, Massachusetts; Division of Neurology (ATW), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; and Departments of Neurology and Pediatrics (ATW), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
Background:
Visual acuity has been a significant outcome measure in clinical trials for patients suffering from neuro-ophthalmological diseases and multiple sclerosis; however, there are limited data on the comparison of various testing strategies in pediatric patients with these disorders. Clinical trials using vision as an outcome could include a variety of tools to assess the acuity, including 2-m and 4-m standardized retroilluminated charts.
Methods:
We investigated the difference in Early Treatment Diabetic Retinopathy Study (ETDRS) scores obtained using 2-m and 4-m charts, as well as the impact of optic neuritis, use of vision correction, age, and gender on visual acuity data from 71 patients with pediatric neuroimmunological conditions in a cross-sectional study.
Results:
We determine that the ETDRS letter scores obtained using 4-m charts are on average 3.43 points less (P = 0.0034) when testing monocular ETDRS letter scores and on average 4.14 points less (P = 0.0008) when testing binocular ETDRS letter scores, relative to that obtained using the 2-m charts. However, we find that when performing monocular testing, optic neuritis in the eye being tested did not result in a statistically significant difference between 2-m and 4-m ETDRS letter scores.
Conclusions:
Although visual acuity charts are formatted by the distance, there are significant differences in the number of letters correctly identified between 2-m and 4-m charts. Although the differences may not impact the clinical acuity, research protocols should consider these differences before collapsing data across disparate studies.
