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Optom Vis Sci. 2014 Oct;91(10):1208-14. doi: 10.1097/OPX.0000000000000365.

Depth-of-field of the accommodating eye.

Author information

1
*MSc †PhD Grupo de Investigación en Optometría, Universidad de Valencia, Valencia, Spain (PB-M, RM-M); Grupo de Ciencias de la Visión, Universidad de Murcia, Murcia, Spain (PB-M, NL-G); and Université Paris-Sud, Orsay, France (RL).

Abstract

PURPOSE:

To obtain experimental values of the depth-of-field (DOFi) of the human eye for different accommodative states.

METHODS:

First, the monochromatic ocular wavefront of seven eyes from young subjects (mean [±SD] age, 29.7 [±7.7] years) was measured at eight different accommodative demands (ADs) (from -1 to 6 diopters [D] in steps of 1 D). Then, in a second part, accommodation was paralyzed and an adaptive optics system was used to correct the aberrations of the paralyzed eye and to simulate, with the aid of an artificial pupil, the wavefront of the accommodated eye. The simulation was performed for each AD measured in the first part of the experiment. A Badal system was used to modify the stimulus vergence so as to obtain three repeated measurements of the subjective DOFi, based on the criterion of an objectionable blur.

RESULTS:

When increasing AD from 0 to 6 D, the mean intersubject pupil diameter and DOFi changed from 5.70 to 4.62 mm and from 0.85 ± 0.26 D to 1.07 ± 0.19 D, respectively. All subjects presented a similar DOFi for all AD (intrasubject SD never exceeded 0.23 D). Paraxial accommodation response showed a lag that increased with the AD. For the lowest (0 D) and the highest (6 D) values of AD, the refractive state of the eye was close to the nearest and furthermost ends of the DOFi, respectively.

CONCLUSIONS:

The visual system takes advantage of the DOFi to change the refractive state less than necessary to form the paraxial image at the retina when it comes to focusing a near target (5 to 6 D of AD). This indicates that the main purpose of accommodation is not to maximize retinal image quality but to form one that is good enough.

PMID:
25148219
PMCID:
PMC4461356
DOI:
10.1097/OPX.0000000000000365
[Indexed for MEDLINE]
Free PMC Article

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