Objective determination of the aniso-accommodative range

P. Carlin, B. Winn, N. C. Strang, H. Culhane, A. S. Eadie

    Research output: Contribution to journalArticlepeer-review

    3 Citations (Scopus)

    Abstract

    Purpose: Recent reports, using subjective measuring techniques, have suggested that a non-conjugate accommodative response is evoked while viewing anisometropic stimuli. Traditional anatomical and physiological models of accommodation are not consistent with the presence of large amounts of aniso accommodation as the response is thought to be consensual and equal. The aim of the study is to determine the range of aniso-accommodation using objective recording methods.
    Method: Accommodation was measured objectively on five visually normal subjects using an open-field infra-red optometer while subjects viewed a photopic Maltese cross stimulus presented in a haploscopic binocular Badal stimulus system at a range of differential vergences (0-2D). The stimulus contained fusion cues to ensure binocular single vision and monocular markers to induce aniso-accommodation. Differential stimulation of accommodation was induced by placing the right and left eye stimuli at different vergences while the subject maintained binocular single vision.
    Results: A normal stimulus response relationship was found for each eye when stimulated monocularly. Binocular stimulation using anisometropic stimuli (Δ0-Δ2D) produced no significant difference in accommodative power between the two eyes. Monocular markers in the stimulus remained perceptually equal across a 0-1.5D range with the binocular accommodative response a lopting the position of lower vergence. Differences in stimulus vergence >2D resulted in the accommodation mechanism being driven by one of the monocular markers (usually at the lower vergence).
    Conclusions: When presented with anisometropic stimuli the accommodation mechanism acts to minimise the monocular defocus error by responding to the position of lower vergence. No evidence of aniso-accommodative responses for maintaining optimal image quality was found. We conclude that binocular accommodation responses are consensual and equal and conform to traditional anatomical and physiological models.
    Original languageEnglish
    Pages (from-to)S163
    JournalInvestigative Ophthalmology and Visual Science
    Volume37
    Issue number3
    Publication statusPublished - 15 Feb 1996

    ASJC Scopus subject areas

    • Ophthalmology
    • Sensory Systems
    • Cellular and Molecular Neuroscience

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