Effects of Spherical and Astigmatic Defocus on Acuity and Contrast Sensitivity: A Comparison of Three Clinical Charts

Bradley, Arthur; Thomas, Tonya N.; Kalaher, Michael; Hoerres, Michael

doi:10.1097/00006324-199106000-00003

Cited by 45 publications

(47 citation statements)

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“…To measure retinal images at the posterior focal line in astigmatic eyes, no spherical lenses were used to compensate for cylindrical powers. 4,6,7,11,12 The effects of the axis orientations were assessed with the 3 types of plus cylinder-oriented axes (WTR, Â180; ATR, Â90; OBL, Â135).…”

Section: Visual Acuity and Reading Performancementioning

confidence: 99%

“…Many studies [4][5][6][7][8][9][10][11][12][13] have assessed the comparability of visual acuity or contrast sensitivity between with-the-rule (WTR) astigmatism, against-the-rule (ATR) astigmatism, and oblique (OBL) astigmatism. However, to our knowledge, there are no detailed clinical studies of the impact of axis orientation on reading performance with different amounts of astigmatism.…”

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confidence: 99%

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Effect of axis orientation on visual performance in astigmatic eyes

Kobashi¹,

Kamiya²,

Shimizu³

et al. 2012

Journal of Cataract and Refractive Surgery

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Section: Visual Acuity and Reading Performancementioning

confidence: 99%

mentioning

confidence: 99%

Effect of axis orientation on visual performance in astigmatic eyes

Kobashi¹,

Kamiya²,

Shimizu³

et al. 2012

Journal of Cataract and Refractive Surgery

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“…In this study, the refractive errors were all myopic ranging between −0.75 and −7.5 D. Holladay et al 5 compiled measurements from 12 previous studies to obtain a reference grid of V versus myopic defocus and pupil diameter. Bradley et al 7 measured visual acuity of four individuals against artificially induced spherical and astigmatic blur. Two of the participants of this study had their accommodation blocked with tropicamide to test how accommodation helps keep high acuity when a low amount of negative defocus is present.…”

Section: Introductionmentioning

confidence: 99%

“…This parameter is not considered in previous models although its effect on visual acuity when positive refractive errors are induced in young individuals is well known. 7 For example, if we want to predict the loss of visual acuity due to the effect of oblique aberrations and/or unwanted astigmatism and sphere error when looking through an ophthalmic lens, we should take into account the capacity of the eye to accommodate and compensate for positive errors, as said before. As expressed in Eq.…”

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confidence: 99%

Phenomenological model of visual acuity

Gómez‐Pedrero

Alonso

2016

J. Biomed. Opt

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Abstract. We propose in this work a model for describing visual acuity (V ) as a function of defocus and pupil diameter. Although the model is mainly based on geometrical optics, it also incorporates nongeometrical effects phenomenologically. Compared to similar visual acuity models, the proposed one considers the effect of astigmatism and the variability of best corrected V among individuals; it also takes into account the accommodation and the "tolerance to defocus," the latter through a phenomenological parameter. We have fitted the model to the V data provided in the works of Holladay et al. and Peters, showing the ability of this model to accurately describe the variation of V against blur and pupil diameter. We have also performed a comparison between the proposed model and others previously published in the literature. The model is mainly intended for use in the design of ophthalmic compensations, but it can also be useful in other fields such as visual ergonomics, design of visual tests, and optical instrumentation.

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“…6,7 Moreover, these chart tests use high-contrast black letters against an unchanging white background of one luminance in the moderate photopic environment of the examination office. For these reasons, other investigators have suggested that these chart tests are not a useful determination of vision in other contrast or luminance environments, and those measurements are poorly correlated with daily living activities 8,9 that require the patient to assess visual stimuli in multiple lighting, contrast, or glare conditions against a varied background color or luminance. 7 Also, many common daily activities require an individual to react to a visual stimulus with limited time or information.…”

Section: Introductionmentioning

confidence: 99%

Visual function assessment in simulated real-life situations in patients with age-related macular degeneration compared to normal subjects

Barteselli¹,

Doede

et al. 2014

Eye

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Purpose To evaluate visual function variations in eyes with age-related macular degeneration (AMD) compared to normal eyes under different light/contrast conditions using a time-dependent visual acuity testing instrument, the Central Vision Analyzer (CVA). Methods Overall, 37 AMD eyes and 35 normal eyes were consecutively tested with the CVA after assessing best-corrected visual acuity (BCVA) using ETDRS charts. The CVA established visual thresholds for three mesopic environments (M1 (high contrast), M2 (medium contrast), and M3 (low contrast)) and three backlight-glare environments (G1 (high contrast, equivalent to ETDRS), G2 (medium contrast), and G3 (low contrast)) under timed conditions. Vision drop across environments was calculated, and repeatability of visual scores was determined. Results BCVA significantly reduced with decreasing contrast in all eyes. M1 scores for BCVA were greater than M2 and M3 (Po0.001); G1 scores were greater than G2 and G3 (Po0.01). BCVA dropped more in AMD eyes than in normal eyes between M1 and M2 (P ¼ 0.002) and between M1 and M3 (P ¼ 0.003). In AMD eyes, BCVA was better using ETDRS charts compared to G1 (Po0.001). The drop in visual function between ETDRS and G1 was greater in AMD eyes compared to normal eyes (P ¼ 0.004). Standard deviations of test-retest ranged from 0.100 to 0.139 logMAR. ConclusionThe CVA allowed analysis of the visual complaints that AMD patients experience with different lighting/contrast time-dependent conditions. BCVA changed significantly under different lighting/contrast conditions in all eyes, however, AMD eyes were more affected by contrast reduction than normal eyes. In AMD eyes, timed conditions using the CVA led to worse BCVA compared to non-timed ETDRS charts.

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Effects of Spherical and Astigmatic Defocus on Acuity and Contrast Sensitivity: A Comparison of Three Clinical Charts

Cited by 45 publications

References 0 publications

Effect of axis orientation on visual performance in astigmatic eyes

Effect of axis orientation on visual performance in astigmatic eyes

Phenomenological model of visual acuity

Visual function assessment in simulated real-life situations in patients with age-related macular degeneration compared to normal subjects

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