Monocular foveal, parafoveal, and perifoveal accommodation response to random defocus step changes

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Title: Monocular foveal, parafoveal, and perifoveal accommodation response to random defocus step changes
Authors: Sharmin, NajninVohnsen, Brian
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Date: 21-Aug-2020
Online since: 2022-08-15T15:58:25Z
Abstract: Accommodation of the human eye relies on multiple factors, including – object size, monochromatic and chromatic aberrations, and vergence, and corrects defocus even in monocular conditions. Previous studies have been done to understand whether the retina can decode the sign of defocus as this may play a role for emmetropization and possibly also accommodation. Yet, findings have not been unambiguous and questions remain. Thus, in this study we tried to understand how accommodation makes use of defocus blur to detect the sign of defocus by performing experiments using a fast wavefront sensor in a vision testing system while eliminating other visual cues that may otherwise confound the analysis. A new automated method has been introduced to study monocular accommodation by using a currentdriven tunable lens (TL) to induce a random sequence of defocus step changes within the accommodative range of each observer. The response was captured in real time using a Hartmann-Shack wavefront sensor (HS-WFS) operating at 20 Hz while detecting aberrations and Zernike coefficients until 4th radial order across a 3 mm limited pupil. Foveal, parafoveal and perifoveal accommodation has been studied for young emmetropes and myopes to determine until which eccentricity accommodation is triggered. Our findings show that the accommodative range diminishes with eccentricity and at 14° (diameter) and beyond it becomes largely absent.
Funding Details: European Commission Horizon 2020
Type of material: Conference Publication
Publisher: SPIE
Copyright (published version): 2020 Society of Photo‑Optical Instrumentation Engineers (SPIE)
Keywords: AccomodationSign of DefocusAberrationsWavefront sensorTunable lensEmmetropizationMyopia
DOI: 10.1117/12.2567419
Language: en
Status of Item: Peer reviewed
Is part of: Lakshminarayanan, V., Creath, K. and Shaw, J.A. Light in Nature VIII
Conference Details: SPIE Optical Engineering + Applications 2020, Online event, 21 August 2020
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