September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Does dynamic accommodation respond to the shape of the blurred retinal image without changes in physical vergence?
Author Affiliations & Notes
  • Ivan Marin-Franch
    Departamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, Burjassot, Valencia, Spain
    Ciencias de la Visión research group, Facultad de Óptica y Optometría, Universidad de Murcia, Murcia, Murcia, Spain
  • Paula Bernal-Molina
    Departamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, Burjassot, Valencia, Spain
    Ciencias de la Visión research group, Facultad de Óptica y Optometría, Universidad de Murcia, Murcia, Murcia, Spain
  • Antonio J Del Águila-Carrasco
    Departamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, Burjassot, Valencia, Spain
    Ciencias de la Visión research group, Facultad de Óptica y Optometría, Universidad de Murcia, Murcia, Murcia, Spain
  • Philip B Kruger
    College of Optometry, State University of New York, New York, New York, United States
  • José-Juan Esteve-Taboada
    Departamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, Burjassot, Valencia, Spain
  • Robert Montés-Micó
    Departamento de Óptica y Optometría y Ciencias de la Visión, Universitat de València, Burjassot, Valencia, Spain
  • Norberto Lopez-Gil
    Ciencias de la Visión research group, Facultad de Óptica y Optometría, Universidad de Murcia, Murcia, Murcia, Spain
  • Footnotes
    Commercial Relationships   Ivan Marin-Franch, None; Paula Bernal-Molina, None; Antonio Del Águila-Carrasco , None; Philip Kruger, None; José-Juan Esteve-Taboada, None; Robert Montés-Micó, None; Norberto Lopez-Gil, None
  • Footnotes
    Support  ERC-2012-StG-309416-SACCO, 15312/PI/10, UV-INV-PREDOC14-179135
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 3952. doi:
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      Ivan Marin-Franch, Paula Bernal-Molina, Antonio J Del Águila-Carrasco, Philip B Kruger, José-Juan Esteve-Taboada, Robert Montés-Micó, Norberto Lopez-Gil; Does dynamic accommodation respond to the shape of the blurred retinal image without changes in physical vergence?. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3952.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Although some eyes use cues from astigmatism and high-order aberrations (HOAs) to detect the sign of defocus of moving monochromatic stimuli, evidence has been found that eyes can also accommodate when all aberrations except defocus are corrected. But, is dynamic accommodation a response to the shape of the blurred image itself or to the physical change in vergence? To tackle this question, simulations of a sinusoidally moving stimulus with and without aberrations were generated and presented to observers.

Methods : Fourteen subjects were recruited with ages between 20 and 38. Subjects had no ocular pathology and astigmatism below 1 D. Subjects were first presented a control condition with a Maltese cross in a monochromatic microdisplay (550 ± 5 nm) through a 4-mm artificial pupil. The stimulus vergence was changed sinusoidally at 0.2 Hz during 25 seconds between 1 D and 3 D from the subject's far point. Aberrations were measured with a Shack-Hartmann sensor at 15 Hz and accommodative response calculated. From these measurements, simulations were generated of a Maltese cross with varying sinusoidal defocus for a 4-mm pupil and (1) no aberrations, (2) subject’s natural aberrations, (3) unbalanced spherical aberration of 0.2 µm, and (4) astigmatism, c2–2, of 0.1 µm. The Figure shows snapshots of the simulations generated at different defocus levels. Simulations were presented in random order during 25 seconds through a 0.75-mm pinhole, effectively eliminating feedback from changes in accommodation. The retinal luminance was kept constant at 100 Td in all control and simulation trials. Each condition was repeated 6 times.

Results : Nine out of 14 subjects accommodated for the control condition when physical vergence changed sinusoidally (average gain was greater than 20 %). The average gains for the 4 simulation conditions over these 9 subjects were very similar at 5−7 %. All pairwise differences in gain between simulation conditions were lower than 2 %. None of them were statistically significant.

Conclusions : No evidence was found that changes in shape of the retinal image of the aberrated eye alone are used as cues to detect the sign of defocus when accommodation feedback is eliminated.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

Simulations of the Maltese cross at −0.5 D and 0.5 D of no aberrations (upper panel) and with a subject’s own aberrations (lower panel).

Simulations of the Maltese cross at −0.5 D and 0.5 D of no aberrations (upper panel) and with a subject’s own aberrations (lower panel).

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