Statistical guidelines for clinical studies of human vision

Armstrong, Richard A.; Davies, Leon N.; Dunne, Mark; Gilmartin, Bernard

doi:10.1111/j.1475-1313.2010.00815.x

Cited by 94 publications

(105 citation statements)

References 50 publications

(70 reference statements)

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“…In FACT 3 cd/m 2 , only three made the highest score and ten just made the entry level at 18 cpd. Skewness combined with only minor differences within the study group suggested the use of nonparametric methods for describing normal data (Armstrong et al 2011). In our study, the population was limited to the age group most relevant for medical selection to posi- tions with high visual demands, and all participants had visual acuity within the limits of acceptance to duty as a naval pilot.…”

Section: Discussionmentioning

confidence: 99%

Contrast sensitivity measured by two different test methods in healthy, young adults with normal visual acuity

Koefoed

Baste

Roumes³

et al. 2014

Acta Ophthalmologica

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ABSTRACT.Purpose: This study reports contrast sensitivity (CS) reference values obtained by two different test methods in a strictly selected population of healthy, young adults with normal uncorrected visual acuity. Based on these results, the index of contrast sensitivity (ICS) is calculated, aiming to establish ICS reference values for this population and to evaluate the possible usefulness of ICS as a tool to compare the degree of agreement between different CS test methods. Methods: Military recruits with best eye uncorrected visual acuity 0.00 LogMAR or better, normal colour vision and age 18-25 years were included in a study to record contrast sensitivity using Optec 6500 (FACT) at spatial frequencies of 1.5, 3, 6, 12 and 18 cpd in photopic and mesopic light and CSV-1000E at spatial frequencies of 3, 6, 12 and 18 cpd in photopic light. Index of contrast sensitivity was calculated based on data from the three tests, and the Bland-Altman technique was used to analyse the agreement between ICS obtained by the different test methods. Results: A total of 180 recruits were included. Contrast sensitivity frequency data for all tests were highly skewed with a marked ceiling effect for the photopic tests. The median ICS for Optec 6500 at 85 cd/m 2 was À0.15 (95% percentile 0.45), compared with À0.00 (95% percentile 1.62) for Optec at 3 cd/m 2 and 0.30 (95% percentile 1.20) FOR CSV-1000E. The mean difference between ICS FACT85 and ICS CSV was À0.43 (95% CI À0.56 to À0.30, p < 0.00) with limits of agreement (LoA) within À2.10 and 1.22. The regression line on the difference of average was near to zero (R 2 = 0.03). Conclusion:The results provide reference CS and ICS values in a young, adult population with normal visual acuity. The agreement between the photopic tests indicated that they may be used interchangeably. There was little agreement between the mesopic and photopic tests. The mesopic test seemed best suited to differentiate between candidates and may therefore possibly be useful for medical selection purposes.

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Section: Discussionmentioning

confidence: 99%

Contrast sensitivity measured by two different test methods in healthy, young adults with normal visual acuity

Koefoed

Baste

Roumes³

et al. 2014

Acta Ophthalmologica

View full text Add to dashboard Cite

show abstract

“…A Friedman 2-way analysis of variance by ranks with multiple comparisons was used to evaluate differences in medians among the three days [32]. The residual standard deviation (r m ) with each test was computed with the data from the subjects who completed a total of 3 sessions (replicates).…”

Section: Reproducibilitymentioning

confidence: 99%

Visual acuity and contrast sensitivity screening with a new iPad application

et al. 2016

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“…A Friedman 2-way analysis of variance by ranks with multiple comparisons was used to evaluate differences in medians among the three days. 41 The residual standard deviation ( with each test was computed with the data from the subjects who completed a total of 3 sessions (replicates). LoAs were estimated again considering models of exchangeable or linked replicates.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Fractal Contact Lenses on Peripheral Refraction in Myopic Model Eyes

Rodríguez‐Vallejo

Benlloch

Pons

et al. 2014

Current Eye Research

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Visual acuity and contrast sensitivity with iPad 2 2. Structured abstract. PurposeTo present two iPad applications (apps) for measuring Visual Acuity (VA) and Contrast Sensitivity Function (CSF) and to assess reliability and agreement with a commercial screening device. MethodsForty-five healthy subjects with monocular corrected visual acuities better than 0.2 logMAR participated in the agreement study of VA and CSF with iPad and Optec 6500. Results MD of VA was 0.06 logMAR better with AmblyopiaVA than with ETDRS (p<0.001) andLoAs were around ±0.2 logMAR. Test-retest reliability was better with AmblyopiaVA (r=0.15) with no statistically significant differences between days (p>0.05). A good agreement with no significant differences (p>0.05) was obtained with ClinicCSF and FACT. MDs were below 0.05 log units at all the spatial frequencies but non-constant LoAs were manifested at 3.6 and 18 cpd. Null hypotheses of same medians along days were accepted for both tests (p>0.05) but reliabilities were poorer with the increment of the spatial frequency. ConclusionsThe iPad tests showed a good agreement with conventional tests and may be a convenient and faster alternative to some existing commercial screening devices. On the other hand future improvements in test-retest reliabilities should be done for the screening of CSF.

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Statistical guidelines for clinical studies of human vision

Abstract: Statistical analysis of data can be complex and different statisticians may disagree as to the correct approach leading to conflict between authors, editors, and reviewers.

Cited by 94 publications

References 50 publications

Contrast sensitivity measured by two different test methods in healthy, young adults with normal visual acuity

Contrast sensitivity measured by two different test methods in healthy, young adults with normal visual acuity

Visual acuity and contrast sensitivity screening with a new iPad application

The Effect of Fractal Contact Lenses on Peripheral Refraction in Myopic Model Eyes

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