Design and validation of a chart‐based measure of the limits of spatial contrast sensitivity

Abstract

Purpose Current chart‐based tests of spatial contrast sensitivity (SCS) with fixed or narrow frequency ranges (≤18 cycles/°) cannot characterise the limits of spatial contrast vision. Here we present the design and validation of a chart‐based measure of the spatial contrast envelope. Methods Following the principles of the standard visual acuity (Bailey‐Lovie) and contrast sensitivity (Pelli‐Robson) charts, a combined spatial‐contrast and visual acuity chart was designed using a language‐independent triangular symbol for a four‐alternative forced‐choice procedure plus chart rotation. Symbol frequencies ranged between 0.38 and 60 cycles/° spaced along 10 radial axes (0.55%–100% contrast). The chart was validated with reference to the Bailey‐Lovie and Pelli‐Robson charts; its reliability and sensitivity to changes in illumination, simulated cataract and blur was evaluated in healthy adults. Results The photopic SCS function could be measured in 5.5 ± 0.5 min; thresholding around the spatial contrast resolution limit reduced completion times to ~2 min. There was good agreement with high‐contrast visual acuity (difference = 0.08 ± 0.02 logMAR) and contrast‐sensitivity at 1.5 cycles/° (0.13 ± 0.06 logCS). Test‐retest reliability was excellent at all spatial frequencies (ICC = 0.99). Mesopic illumination or simulated cataract caused a generalised SCS loss; myopic blur reduced high‐frequency sensitivity. Spatial contrast sensitivity was independent of radial axis orientation (cardinal or oblique). Conclusions The chart provides a time‐efficient, reliable and inexpensive measure of SCS with applications in research and clinic for detecting subtle deficits in early stages of ocular and neurological conditions that often manifest at higher frequencies. It is sensitive to vision changes occurring in dim lighting and with simulated cataract and blur. The chart is available open‐access for self‐printing; contrast variation in print can be controlled through user calibration and/or establishing normative SCS functions using the theoretical values.

Melanopsin photoreception differentially modulates rod-mediated and cone-mediated human temporal vision

“…1700000510) and followed the tenets of the Declaration of Helsinki; written informed consent was obtained from all participants. Three healthy observers (all males; O1, 31 years; O2, 29 years; and O3, 38 years) participated in the study who had trichromatic color vision (Ishihara pseudoisochromatic plates and L’anthony Desaturated D-15 Test), visual acuity of 0.0 logMAR (6/6) or better, age-normal spatial contrast sensitivity (Combined Spatial Contrast and Visual Acuity chart ( Adhikari et al., 2022 ), no ocular diseases as confirmed with ophthalmoscopy, fundus photography (Canon Non Mydriatic Retinal Camera, CR-DGi, Canon Inc., Tokyo, Japan), optical coherence topography (RS-3000 OCT RetinaScan Advance, Nidek Co., Ltd., Tokyo, Japan) and intraocular pressure measurement (<21 mmHg) (Icare® ic100; Icare Finland Oy, Vantaa, Finland), and no systemic disease. Two observers were authors, and one was an experienced observer who was naïve to the purpose of the experiment.…”

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“…logMAR acuity chart is based on early treatment of diabetic screening which gives the proper acuity of human eyes and removes the chance of error. 10 The orthoptics assessment was assessed with different instruments. A cover uncovers test was done by the black plastic opaque occlude at distance 6 m and near 33cm.…”

Tratamento da ambliopia refrativa após o período sensitivo com aprendizagem perceptual

“…A pesquisa foi aprovada pelo Comitê de Ética em Pesquisa com seres humanos da Universidade do Contestado. Foi medida a SC pré e pós terapia, em alto e baixo contraste em visão de longe (VL) com Bailey Lovie valores como base de baixo contraste, baseado em Michelson 10%, demonstrados em Adhikari et al 15 .…”