lnu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Objectively Determined Refraction Improves Peripheral Vision
Linnaeus University, Faculty of Health and Life Sciences, Department of Medicine and Optometry.ORCID iD: 0000-0002-8365-0601
Linnaeus University, Faculty of Health and Life Sciences, Department of Medicine and Optometry.ORCID iD: 0000-0002-3745-0035
Royal Institute of Technology KTH.
Royal Institute of Technology KTH.
Show others and affiliations
2014 (English)In: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 91, no 7, 740-746 p.Article in journal (Refereed) Published
Abstract [en]

Purpose. The purpose of this study was twofold: to verify a fast, clinically applicable method for determining off-axis refraction and to assess the impact of objectively obtained off-axis refractive correction on peripheral low-contrast visual acuity. Methods. We measured peripheral low-contrast resolution acuity with Gabor patches both with and without off-axis correction at 20 degrees in the nasal visual field of 10 emmetropic subjects; the correction was obtained using a commercial open-field Hartmann-Shack wavefront sensor, the COAS-HD VR aberrometer. Off-axis refractive errors were calculated for a 5-mm circular pupil inscribed within the elliptical wavefront by COAS using the instruments' inbuilt "Seidel sphere" method. Results. Most of the subjects had simple myopic astigmatism, at 20 degrees in the nasal visual field ranging from -1.00 to -2.00 DC, with axis orientations generally near 90 degrees. The mean uncorrected and corrected low-contrast resolution acuities for all subjects were 0.92 and 0.86 logMAR, respectively (an improvement of 0.06 logMAR). For subjects with a scalar power refractive error of 1.00 diopters or more, the average improvement was 0.1 logMAR. The observed changes in low-contrast resolution acuity were strongly correlated with off-axis astigmatism (Pearson r = 0.95; p < 0.0001), the J(180) cross-cylinder component (Pearson r = 0.82; p = 0.0034), and power scalar (Pearson r = -0.75; p = 0.0126). Conclusions. The results suggest that there are definite benefits in correcting even moderate amounts of off-axis refractive errors; in this study, as little as -1.50 DC of off-axis astigmatism gave improvements of up to a line in visual acuity. It may be even more pertinent for people who rely on optimal peripheral visual function, specifically those with central visual field loss; the use of open-field aberrometers could be clinically useful in rapidly determining off-axis refractive errors specifically for this patient group who are generally more challenging to refract.

Place, publisher, year, edition, pages
2014. Vol. 91, no 7, 740-746 p.
Keyword [en]
visual acuity, low-contrast resolution acuity, off-axis refractive errors, peripheral vision, off-axis astigmatism, macular degeneration, AMD
National Category
Ophthalmology
Research subject
Natural Science, Optometry
Identifiers
URN: urn:nbn:se:lnu:diva-36833DOI: 10.1097/OPX.0000000000000301ISI: 000338778400010Scopus ID: 2-s2.0-84903754538OAI: oai:DiVA.org:lnu-36833DiVA: diva2:745483
Available from: 2014-09-10 Created: 2014-09-10 Last updated: 2017-01-27Bibliographically approved
In thesis
1. Improving Peripheral Vision Through Optical Correction and Stimulus Motion
Open this publication in new window or tab >>Improving Peripheral Vision Through Optical Correction and Stimulus Motion
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The loss of central vision subsequent to macular disease is often extremely debilitating. People with central field loss (CFL) must use other peripheral areas of the retina in order to see; areas with inferior resolution capacity, which are also affected by off-axis optical errors. The overall aim of the work encompassed by this thesis was to identify and evaluate methods of improving vision for people with CFL; with focus on the effects of off-axis optical correction and stimulus motion on resolution acuity and contrast sensitivity.

Off-axis optical errors were measured using a commercially-available COAS-HD VR open-view aberrometer. We used adaptive psychophysical methods to evaluate grating resolution acuity and contrast sensitivity in the peripheral visual field; drifting gratings were employed to   measure the effect of motion on these two measures of visual performance. The effect of sphero-cylindrical correction and stimulus motion on visual performance in healthy eyes and in subjects with CFL was also studied; in addition, the effect of adaptive optics aberration correction was examined in one subject with CFL.

The COAS-HD aberrometer provided rapid and reliable measurements of off-axis refractive errors. Correction of these errors gave improvements in low-contrast resolution acuity in subjects with higher amounts of oblique astigmatism. Optical correction also improved high-contrast resolution acuity in most subjects with CFL, but not for healthy subjects. Adaptive optics correction improved both high and low contrast resolution acuity in the preferred retinal locus of a subject with CFL. The effect of stimulus motion depended on spatial frequency; motion of 7.5 Hz improved contrast sensitivity for stimuli of low spatial frequency in healthy and CFL subjects. Motion of 15 Hz had little effect on contrast sensitivity for low spatial frequency but resulted in reduced contrast sensitivity for higher spatial frequencies in healthy subjects. Finally, high-contrast resolution acuity was relatively insensitive to stimulus motion in the periphery.

This thesis has served to broaden the knowledge regarding peripheral optical errors, stimulus motion and their effects on visual function, both in healthy subjects and in people with CFL. Overall it has shown that correction of off-axis refractive errors is important for optimizing peripheral vision in subjects with CFL; the use of an open-view aberrometer simplifies the determination of these errors. In addition, moderate stimulus motion can have a beneficial effect on contrast sensitivity for objects of predominantly low spatial frequency.

Place, publisher, year, edition, pages
Växjö: Linnaeus University Press, 2016. 172 p.
Series
Linnaeus University Dissertations, 248/2016
Keyword
absolute central scotoma, central visual field loss, eccentric viewing, preferred retinal locus, open-view aberrometer, off-axis refractive errors, eccentric correction, dynamic visual acuity, spatial contrast sensitivity, temporal contrast sensitivity, spatio-temporal contrast sensitivity
National Category
Other Medical Sciences not elsewhere specified
Research subject
Natural Science, Optometry; Natural Science, Biomedical Sciences
Identifiers
urn:nbn:se:lnu:diva-52286 (URN)978-91-88357-14-4 (ISBN)
Public defence
2016-05-19, N2007, Smålandsgatan 26E, Kalmar, 09:45 (English)
Opponent
Supervisors
Available from: 2016-05-13 Created: 2016-04-28 Last updated: 2017-01-27Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Lewis, PeterBaskaran, KarthikeyanGustafsson, Jörgen
By organisation
Department of Medicine and Optometry
In the same journal
Optometry and Vision Science
Ophthalmology

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 81 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf