Too many shades of grey: photometrically and spectrally mismatched targets and backgrounds in printed acuity tests for infants and young children

Vivas-Mateos, G., Livingstone, I. A.T., Hamilton, R. , Cheema, A. and Giardini, M. E. (2020) Too many shades of grey: photometrically and spectrally mismatched targets and backgrounds in printed acuity tests for infants and young children. Translational Vision Science and Technology, 9(12), 12. (doi: 10.1167/tvst.9.12.12) (PMID:33240565) (PMCID:PMC7671855)

Abstract

Purpose: Acuity tests for infants and young children use preferential looking methods that require a perceptual match of brightness and color between grey background and target spatial average. As a first step in exploring this matching, this article measures photometric and colorimetric matches in these acuity tests. Methods: The luminance, uniformity, contrast, and color spectra of Teller Acuity Cards, Keeler Acuity Cards for Infants, and Lea Paddles under ambient, warm, and cold lighting, and of grey-emulating patterns on four digital displays, were measured. Five normal adults’ acuities were tested at 10 m observationally. Results: Luminance and spectral mismatches between target and background were found for the printed tests (Weber contrasts of 0.3% [Teller Acuity Cards], −1.7% [Keeler Acuity Cards for Infants], and −26% [Lea Paddles]). Lighting condition had little effect on contrast, and all printed tests and digital displays met established adult test luminance and uniformity standards. Digital display grey backgrounds had very similar luminance and color whether generated by a checkerboard, vertical grating, or horizontal grating. Improbably good psychophysical acuities (better than −0.300 logMAR: (logarithm of the minimum angle of resolution)) were recorded from adults using the printed tests at 10 m, but not using the digital test Peekaboo Vision. Conclusions: Perceptible contrast between target and background could lead to an incorrectly measured, excessively good acuity. It is not clear whether the luminance and spectral contrasts described here have clinically meaningful consequences for the target patient group, but they may be avoidable using digital tests. Translational Relevance: Current clinical infant acuity tests present photometric mismatches that may return inaccurate testing results.

• Item Type: Articles
• Additional Information: Supported by the UK Engineering and Physical Sciences Research Council - EPSRC Centre for Doctoral Training in Medical Devices and Health Technologies, University of Strathclyde, (Grant Ref. EP/LO15595/1), and of the Teresa Rosenbaum Golden Charitable Trust (Rosetrees Trust, Grant Ref. M270).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hamilton, Dr Ruth
• Authors: Vivas-Mateos, G., Livingstone, I. A.T., Hamilton, R., Cheema, A., and Giardini, M. E.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Journal Name: Translational Vision Science and Technology
• Publisher: Association for Research in Vision and Ophthalmology
• ISSN: 2164-2591
• ISSN (Online): 2164-2591
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Translational Vision Science and Technology 9(12):12
• Publisher Policy: Reproduced under a Creative Commons Licence