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Torsten Strasser, Bettina Spieth, Eberhart Zrenner, Dorothea Besch, Carina Kelbsch; Can you see the panda? Visual acuity assessment using the pandacuity test in children – preliminary results. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5199. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Visual acuity (VA) testing in preschool or developmentally delayed children can be challenging and is highly reliant on the child’s compliance. Typically used acuity charts with simple optotypes (e. g. Landolt-C, Snellen-E, LEA) could bore the child, making it difficult to distinguish between non-compliance and decreased VA. At ARVO 2017, we presented an approach for assessing VA using the hidden panda illusion, in which the silhouette of a panda is formed by varying the thickness of zig-zagged lines (Fig. 1a). We found a linear relationship between the spatial frequency of the lines and the VA. Here we present results of a pilot study on using the hidden panda illusion for assessing VA in preschool children.
A flip book (30x30 cm, Fig. 1b) with a panda illusion-like image with decreasing VA score on each page was created based on the linear relationship described previously (Fig. 1c).The pandacuity test was performed on both eyes of 20 randomly selected children (4–12 yrs, Fig. 2a) in addition to conventional VA testing (depending on the child’s capabilities: Snellen-E, LEA symbols, or numbers) during a routine visit to the pediatric ophthalmology unit of the University Eye Hospital Tuebingen. Acuity charts were presented at 3 m distance and performed monocularly with best corrected visual acuity in a quiet room with standardized lighting by a trained orthoptist. LogMAR scaled VA scores of both eyes were used for statistical analysis.
All children completed the test successfully. One eye was excluded since the child could not complete the test. VA assessed using conventional eye charts showed a strong correlation to VA assessed using the pandacuity test (r = .78, n = 39, p < .001, Fig. 2b). A two-tailed paired sample t-test showed no statistically significant differences between the two methods (t(38) = -1.3838, p = .1751, MD = 0.06, Fig. 2c).
The pandacuity test is rapid, simple and well-accepted, making it a suitable addition to conventional acuity testing for clinical assessment of VA in children. Because of its counter-intuitive application (more seen images means worse VA), it can be used to cross-validate conventional acuity tests to assure the child’s compliance. We plan to validate the pandacuity test in comparison to conventional VA testing in a prospective study including 150 children.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
The pandacuity test
Subject demographics and statistics
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