Too Many Shades of Grey: Photometrically and Spectrally Mismatched Targets and Backgrounds in Printed Acuity Tests for Infants and Young Children
| Autor: | Ruth Hamilton, Mario Giardini, Arsalan Cheema, Iain A.T. Livingstone, Guillermo Vivas-Mateos |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Adult Brightness Visual acuity genetic structures visual acuity Biomedical Engineering Spatial average Teller acuity cards Luminance Article Peekaboo Vision Photometry 03 medical and health sciences 0302 clinical medicine medicine Humans Lea Paddles Keeler acuity cards Patient group Child Lighting Mathematics Teller Cards Vision Tests Infant Reference Standards Cardiff Cards Ophthalmology 030104 developmental biology Child Preschool 030221 ophthalmology & optometry Optometry Keeler Acuity Cards medicine.symptom |
| Zdroj: | Translational Vision Science & Technology |
| ISSN: | 2164-2591 |
| Popis: | 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.\ud \ud 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.\ud \ud 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.\ud \ud 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.\ud \ud Translational Relevance: Current clinical infant acuity tests present photometric mismatches that may return inaccurate testing results. |
| Databáze: | OpenAIRE |
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