Distance stereoacuity in prism-induced convergence stress

Laird, Philip W.; Hatt, Sarah R.; Holmes, Jonathan M.

doi:10.1016/j.jaapos.2008.01.013

Cited by 15 publications

(14 citation statements)

References 15 publications

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“…In general, participants score better on “real depth” tests such as those used here than on “pure disparity” tests such as random-dot patterns, and our results are consistent with this [38]. Conversely, distance stereoacuity in prism-induced convergence stress degrades more rapidly for the “real depth” FD2 than the “pure disparity” Distance Randot [42], [43]. The effects of age may also be less pronounced on “real depth” tasks [14].…”

Section: Discussionsupporting

confidence: 82%

Stereoacuity with Frisby and Revised FD2 Stereo Tests

Bohr

Read

2013

PLoS ONE

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We compared near stereoacuity, measured with the Frisby test, and distance stereoacuity, measured with the revised Frisby-Davis (FD2) test, enabling a comparison with the original version of the FD2. In the revised version of the FD2 test, a white background is used instead of a backlit background. We also examined the effect of age, gender and visual problems. We used the Frisby test at distances ranging from 30–80 cm and FD2 at 6 m. The best possible score was 20 seconds of arc (arcsec) on the Frisby and 5 arcsec on the FD2; participants who could not perform a test despite demonstrating understanding of it were classed as stereonegative. We examined both the whole population recruited, and a sub-population screened so as to exclude visual problems. We analysed our results in three age-groups: “visually developing” (36 children aged 5–10 years); “visually mature” (300 participants aged 11–49 years) and “older” (29 participants aged 50–82). In the whole population, the median stereoacuity on the Frisby test was 25, 20 and 85 arcsec in the three age-groups. In the sub-population with no visual problems, median Frisby stereoacuity was similar at 20, 20 and 80 arcsec respectively. On the FD2, the medians were 10, 10, 20 arcsec for the whole population and 7.5, 10 and 12.5 for the sub-population. Children were more likely than adults to be stereonegative on the FD2, although none of the children were stereonegative on the Frisby. The two tests showed fair agreement when used to classify people into three categories of stereovision. Poor stereovision was often associated with binocular problems such as tropia, but with many exceptions. In line with previous studies, we found improvements in measured stereoacuity in childhood and declines in late adulthood. The new FD2 test gives comparable values to the original FD2.

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Section: Discussionsupporting

confidence: 82%

Stereoacuity with Frisby and Revised FD2 Stereo Tests

Bohr

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2013

PLoS ONE

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“…40,41 The possible mechanism for reduced stereoacuity under vergence stress includes temporary anomalous retinal correspondence, which are small shifts in retinal correspondence that can occur without disrupting Panum's fusional process. 42 A significant correlation between near lateral phoria and stereoacuity corroborates findings of other studies that found that even small amounts of esophoria negatively impact stereoacuity more than exophoria.…”

Section: Discussionsupporting

confidence: 88%

Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13–18 years

Wajuihian¹,

Hansraj²

2018

Afr. vis. eye health

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Aim:The aim of this study was to explore possible associations between stereoacuity and refractive, accommodative and vergence anomalies. Methods:The study design was cross-sectional and comprised data from 1056 high school children aged between 13 and 18 years; mean age and standard deviation were 15.89 ± 1.58 years. Using a multi-stage random cluster sampling, participants were selected from 13 high schools out of a sample frame of 60 schools in the municipality concerned. In the final sample, 403 (38%) were males and 653 (62%) females. Refractive errors, heterophoria, near point of convergence, fusional vergences and accommodative functions (amplitude, facility, response and relative) were evaluated. Stereoacuity was evaluated using the Randot stereotest and recorded in seconds of arc where reduced stereoacuity was defined as worse than 40 s arc.Results: Overall, the mean stereoacuities (in seconds of arc) of the children with anomalies were the following: those with refractive errors (52.6 ± 36.9), with accommodative anomalies (53.1 ± 34.1) and with vergence anomalies (48.29 ± 31.1). The mean stereoacuity of those with vergence anomalies was significantly better than that of those with either refractive errors or accommodative anomalies (p = 0.02). In the refractive error category, only anisometropia had significantly reduced mean stereoacuity compared to emmetropia (Mann-Whitney U: p = 0.01). The mean stereoacuity of cases of accommodative anomalies was significantly reduced compared to those without such anomalies (Mann-Whitney U: p = 0.01). Similarly, the mean stereoacuity of cases with vergence anomalies was significantly reduced compared to those without vergence anomalies (p = 0.02). Conclusion:Refractive errors, accommodative or vergence anomalies are more likely to have reduced mean stereoacuity than cases without such anomalies. Refractive errors or accommodative anomalies had significantly more reduced stereoacuity than vergence anomalies. These findings suggest that the Randot stereotest could be used to identify those with such anomalies, and this study extends knowledge regarding the possible use of stereoacuity as a useful tool to screen for binocular anomalies. Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13-18 yearsRead online:Scan this QR code with your smart phone or mobile device to read online.

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“…Nevertheless, previous studies in adults by our group have shown no apparent fatigue or learning effect when testing stereoacuity. 10, 27 …”

Section: Discussionmentioning

confidence: 99%

The effect of induced monocular blur on measures of stereoacuity

Odell

Hatt

Leske

et al. 2009

Journal of American Association for Pediatric Ophthalmology and

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Purpose To determine the effect of induced monocular blur on stereoacuity measured using ‘real depth’ and ‘random dot’ tests. Methods Monocular visual acuity deficits (range 20/15 to 20/1600) were induced with 7 different Bangerter filters (<0.1, 0.1, 0.2, 0.3, 0.4, 0.8, and 1.0) in 15 visually normal adults. Stereoacuity was measured using Frisby and Frisby Davis Distance (FD2) ‘real depth’ tests and Preschool Randot (PSR) and Distance Randot (DR) ‘random dot’ tests. Stereoacuity results were grouped as either ‘fine’ (≤60 arcsec), ‘moderate’ (>60 and ≤200 arcsec), or ‘coarse/nil’ (>200 arcsec to nil) stereo. Results Across visual acuity deficits, stereoacuity was more severely degraded with random dot (PSR, DR) than with real depth (Frisby, FD2) tests. Degradation to ‘worse than fine’ stereoacuity consistently occurred at 0.7 logMAR (20/100) or worse for Frisby, 0.1 logMAR (20/25) or worse for PSR, 0.1 logMAR (20/25) or worse for FD2. There was no meaningful threshold for the DR since ‘worse than fine’ stereoacuity was associated with −0.1 logMAR (20/15). Course/nil stereoacuity was consistently associated with 1.2 logMAR (20/320) or worse for Frisby, 0.8 logMAR (20/125) or worse for PSR, 1.1 logMAR (20/250) or worse for FD2, and 0.5 logMAR (20/63) or worse for DR. Conclusions Stereoacuity thresholds are more easily degraded by reduced monocular visual acuity using random dot tests (PSR and DR) than real depth tests (Frisby and FD2). We have defined levels of monocular visual acuity degradation associated with ‘fine’ and ‘nil’ stereoacuity. These findings have important implications for testing stereoacuity in clinical populations.

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Distance stereoacuity in prism-induced convergence stress

Cited by 15 publications

References 15 publications

Stereoacuity with Frisby and Revised FD2 Stereo Tests

Stereoacuity with Frisby and Revised FD2 Stereo Tests

Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13–18 years

The effect of induced monocular blur on measures of stereoacuity

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