Effect of defocus on visual field measurement

Atchison, David A. (1987) Effect of defocus on visual field measurement. Ophthalmic and Physiological Optics, 7(3), pp. 259-265.

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Defocus increased visual field contrast thresholds for stimuli equal to or smaller than Goldmann perimeter target III (26 min arc diameter). Beyond 30 degrees - 40 degrees from the centre of the visual field, defocus had little effect on contrast thresholds. For accurate clinical perimetry, ametropia and presbyopia should be corrected for small targets (≤ target III) within 30 degrees - 40 degrees of fixation with either a spectacle lens (if required power less than ± 10 D) or a contact lens. Larger stimuli are little affected by defocus. Outside this central 30 degrees - 40 degrees field, correction with contact lenses should be provided if fixation is poor due to ametropia. Scotomata for which no cause is evident should be further investigated to find whether they have a refractive basis.

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ID Code: 4663
Item Type: Journal Article
Refereed: Yes
Additional Information: For more information or for a copy of this article contact: d.atchison@qut.edu.au
Keywords: visual field, defocus, contrast threshold, perimetry, ametropia
DOI: 10.1111/j.1475-1313.1987.tb00743.x
ISSN: 0275-5408
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 1987 Blackwell Publishing
Copyright Statement: The definitive version is available at www.blackwell-synergy.com
Deposited On: 17 Aug 2006 00:00
Last Modified: 15 Jan 2009 07:08

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