Effect of simulated refractive error on adult visual acuity for paediatric tests

Nabin Paudel, Robert J. Jacobs, Rebecca Sloan, Sarah Denny, Kimberley Shea, Benjamin Thompson, Nicola Anstice

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Purpose: Although vanishing optotype preferential-looking tasks are commonly used to measure visual acuity (VA), the relative sensitivity of these tests to refractive error is not well understood. To address this issue, we determined the effect of spherical and astigmatic simulated refractive errors on adult VA measures obtained using vanishing optotypes, picture optotypes and Sloan letters. Methods: VA was determined uniocularly for adults under conditions of spherical (0.0–3.0 DS; n = 23) and astigmatic (0.0–3.0 DC at 90° and 180°; n = 20) defocus using the Cardiff Acuity Test (vanishing optotypes), crowded linear Lea Symbols (picture-optotype recognition task) and the Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart. Results: The Cardiff Acuity Test over-estimated VA compared with the Lea Symbols and ETDRS charts in both focused and defocused conditions. The mean difference between the Cardiff Acuity Test and the ETDRS chart was 0.31 logMAR (95% limits of agreement (LOA) 0.10–0.52 logMAR) in focused conditions and 0.64 logMAR (95% LOA 0.25–1.05 logMAR) with 3D of spherical defocus. Defocus degraded VA on all charts, however there was a significant chart-by-defocus interaction whereby the Cardiff Acuity Test was more resistant to the effects of both spherical (P < 0.0001) and cylindrical (P < 0.001) optical defocus than the recognition acuity tasks at all defocus levels. Conclusion: Although the Cardiff Acuity Test provides an easy method for VA measurement in infants and toddlers, there is a considerable overestimation of VA compared with recognition acuity tasks particularly in the presence of defocus. A simple correction factor (of for example three lines overestimate) cannot be applied to Cardiff acuity measures as there is increasing over-estimation of VA with increasing defocus. Infants with significant refractive error may fall within normal visual acuity ranges for the Cardiff Acuity Test.

Original languageEnglish
Pages (from-to)521-530
Number of pages10
JournalOphthalmic and Physiological Optics
Volume37
Issue number4
DOIs
Publication statusPublished - 1 Jul 2017
Externally publishedYes

Fingerprint

Refractive Errors
Visual Acuity
Pediatrics
Diabetic Retinopathy
Therapeutics

Cite this

Paudel, Nabin ; Jacobs, Robert J. ; Sloan, Rebecca ; Denny, Sarah ; Shea, Kimberley ; Thompson, Benjamin ; Anstice, Nicola. / Effect of simulated refractive error on adult visual acuity for paediatric tests. In: Ophthalmic and Physiological Optics. 2017 ; Vol. 37, No. 4. pp. 521-530.
@article{13a5870af5274db9a9cfd52a9cc2cf48,
title = "Effect of simulated refractive error on adult visual acuity for paediatric tests",
abstract = "Purpose: Although vanishing optotype preferential-looking tasks are commonly used to measure visual acuity (VA), the relative sensitivity of these tests to refractive error is not well understood. To address this issue, we determined the effect of spherical and astigmatic simulated refractive errors on adult VA measures obtained using vanishing optotypes, picture optotypes and Sloan letters. Methods: VA was determined uniocularly for adults under conditions of spherical (0.0–3.0 DS; n = 23) and astigmatic (0.0–3.0 DC at 90° and 180°; n = 20) defocus using the Cardiff Acuity Test (vanishing optotypes), crowded linear Lea Symbols (picture-optotype recognition task) and the Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart. Results: The Cardiff Acuity Test over-estimated VA compared with the Lea Symbols and ETDRS charts in both focused and defocused conditions. The mean difference between the Cardiff Acuity Test and the ETDRS chart was 0.31 logMAR (95{\%} limits of agreement (LOA) 0.10–0.52 logMAR) in focused conditions and 0.64 logMAR (95{\%} LOA 0.25–1.05 logMAR) with 3D of spherical defocus. Defocus degraded VA on all charts, however there was a significant chart-by-defocus interaction whereby the Cardiff Acuity Test was more resistant to the effects of both spherical (P < 0.0001) and cylindrical (P < 0.001) optical defocus than the recognition acuity tasks at all defocus levels. Conclusion: Although the Cardiff Acuity Test provides an easy method for VA measurement in infants and toddlers, there is a considerable overestimation of VA compared with recognition acuity tasks particularly in the presence of defocus. A simple correction factor (of for example three lines overestimate) cannot be applied to Cardiff acuity measures as there is increasing over-estimation of VA with increasing defocus. Infants with significant refractive error may fall within normal visual acuity ranges for the Cardiff Acuity Test.",
keywords = "astigmatic defocus, Cardiff Acuity test, children's vision, Early Treatment of Diabetic Retinopathy Study chart, Lea symbols, spherical defocus, visual acuity",
author = "Nabin Paudel and Jacobs, {Robert J.} and Rebecca Sloan and Sarah Denny and Kimberley Shea and Benjamin Thompson and Nicola Anstice",
year = "2017",
month = "7",
day = "1",
doi = "10.1111/opo.12387",
language = "English",
volume = "37",
pages = "521--530",
journal = "British Journal of Physiological Optics",
issn = "0275-5408",
publisher = "Wiley-Blackwell",
number = "4",

}

Effect of simulated refractive error on adult visual acuity for paediatric tests. / Paudel, Nabin; Jacobs, Robert J.; Sloan, Rebecca; Denny, Sarah; Shea, Kimberley; Thompson, Benjamin; Anstice, Nicola.

In: Ophthalmic and Physiological Optics, Vol. 37, No. 4, 01.07.2017, p. 521-530.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of simulated refractive error on adult visual acuity for paediatric tests

AU - Paudel, Nabin

AU - Jacobs, Robert J.

AU - Sloan, Rebecca

AU - Denny, Sarah

AU - Shea, Kimberley

AU - Thompson, Benjamin

AU - Anstice, Nicola

PY - 2017/7/1

Y1 - 2017/7/1

N2 - Purpose: Although vanishing optotype preferential-looking tasks are commonly used to measure visual acuity (VA), the relative sensitivity of these tests to refractive error is not well understood. To address this issue, we determined the effect of spherical and astigmatic simulated refractive errors on adult VA measures obtained using vanishing optotypes, picture optotypes and Sloan letters. Methods: VA was determined uniocularly for adults under conditions of spherical (0.0–3.0 DS; n = 23) and astigmatic (0.0–3.0 DC at 90° and 180°; n = 20) defocus using the Cardiff Acuity Test (vanishing optotypes), crowded linear Lea Symbols (picture-optotype recognition task) and the Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart. Results: The Cardiff Acuity Test over-estimated VA compared with the Lea Symbols and ETDRS charts in both focused and defocused conditions. The mean difference between the Cardiff Acuity Test and the ETDRS chart was 0.31 logMAR (95% limits of agreement (LOA) 0.10–0.52 logMAR) in focused conditions and 0.64 logMAR (95% LOA 0.25–1.05 logMAR) with 3D of spherical defocus. Defocus degraded VA on all charts, however there was a significant chart-by-defocus interaction whereby the Cardiff Acuity Test was more resistant to the effects of both spherical (P < 0.0001) and cylindrical (P < 0.001) optical defocus than the recognition acuity tasks at all defocus levels. Conclusion: Although the Cardiff Acuity Test provides an easy method for VA measurement in infants and toddlers, there is a considerable overestimation of VA compared with recognition acuity tasks particularly in the presence of defocus. A simple correction factor (of for example three lines overestimate) cannot be applied to Cardiff acuity measures as there is increasing over-estimation of VA with increasing defocus. Infants with significant refractive error may fall within normal visual acuity ranges for the Cardiff Acuity Test.

AB - Purpose: Although vanishing optotype preferential-looking tasks are commonly used to measure visual acuity (VA), the relative sensitivity of these tests to refractive error is not well understood. To address this issue, we determined the effect of spherical and astigmatic simulated refractive errors on adult VA measures obtained using vanishing optotypes, picture optotypes and Sloan letters. Methods: VA was determined uniocularly for adults under conditions of spherical (0.0–3.0 DS; n = 23) and astigmatic (0.0–3.0 DC at 90° and 180°; n = 20) defocus using the Cardiff Acuity Test (vanishing optotypes), crowded linear Lea Symbols (picture-optotype recognition task) and the Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart. Results: The Cardiff Acuity Test over-estimated VA compared with the Lea Symbols and ETDRS charts in both focused and defocused conditions. The mean difference between the Cardiff Acuity Test and the ETDRS chart was 0.31 logMAR (95% limits of agreement (LOA) 0.10–0.52 logMAR) in focused conditions and 0.64 logMAR (95% LOA 0.25–1.05 logMAR) with 3D of spherical defocus. Defocus degraded VA on all charts, however there was a significant chart-by-defocus interaction whereby the Cardiff Acuity Test was more resistant to the effects of both spherical (P < 0.0001) and cylindrical (P < 0.001) optical defocus than the recognition acuity tasks at all defocus levels. Conclusion: Although the Cardiff Acuity Test provides an easy method for VA measurement in infants and toddlers, there is a considerable overestimation of VA compared with recognition acuity tasks particularly in the presence of defocus. A simple correction factor (of for example three lines overestimate) cannot be applied to Cardiff acuity measures as there is increasing over-estimation of VA with increasing defocus. Infants with significant refractive error may fall within normal visual acuity ranges for the Cardiff Acuity Test.

KW - astigmatic defocus

KW - Cardiff Acuity test

KW - children's vision

KW - Early Treatment of Diabetic Retinopathy Study chart

KW - Lea symbols

KW - spherical defocus

KW - visual acuity

U2 - 10.1111/opo.12387

DO - 10.1111/opo.12387

M3 - Article

VL - 37

SP - 521

EP - 530

JO - British Journal of Physiological Optics

JF - British Journal of Physiological Optics

SN - 0275-5408

IS - 4

ER -