Image Quality in the Human Eye

1970 ◽  
Vol 17 (9) ◽  
pp. 641-658 ◽  
Author(s):  
G. Westheimer
Keyword(s):  
Image Quality ◽  
Human Eye

Off-axis image quality in the human eye

1981 ◽  
Vol 21 (4) ◽  
pp. 445-455 ◽  
Author(s):  
J.A.M. Jennings ◽  
W.N. Charman
Keyword(s):  
Image Quality ◽  
Human Eye

Image quality of the human eye for eccentric entrance pupils

1983 ◽  
Vol 23 (5) ◽  
pp. 573-579 ◽  
Author(s):  
A. Van Meeteren ◽  
C.J.W. Dunnewold
Keyword(s):  
Image Quality ◽  
Human Eye

Aberrations and retinal image quality of the normal human eye

1997 ◽  
Vol 14 (11) ◽  
pp. 2873 ◽  
Author(s):  
Junzhong Liang ◽  
David R. Williams
Keyword(s):  
Image Quality ◽  
Retinal Image ◽  
Human Eye ◽  
Normal Human

scholarly journals Retinal image quality in the human eye as a function of the accommodation

1998 ◽  
Vol 38 (19) ◽  
pp. 2897-2907 ◽  
Author(s):  
Norberto López-Gil ◽  
Ignacio Iglesias ◽  
Pablo Artal
Keyword(s):  
Image Quality ◽  
Retinal Image ◽  
Human Eye

scholarly journals Effect of Phenylephrine on the Accommodative System

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
José J. Esteve-Taboada ◽  
Antonio J. Del Águila-Carrasco ◽  
Paula Bernal-Molina ◽  
Teresa Ferrer-Blasco ◽  
Norberto López-Gil ◽  
...  
Keyword(s):  
Image Quality ◽  
Retinal Image ◽  
Ciliary Muscle ◽  
Depth Of Focus ◽  
Pharmacological Agents ◽  
The Real ◽  
Phenylephrine Hydrochloride ◽  
Main Research ◽  
Human Eye ◽  
Real Effects

Accommodation is controlled by the action of the ciliary muscle and mediated primarily by parasympathetic input through postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia. During accommodation the pupil constricts to increase the depth of focus of the eye and improve retinal image quality. Researchers have traditionally faced the challenge of measuring the accommodative properties of the eye through a small pupil and thus have relied on pharmacological agents to dilate the pupil. Achieving pupil dilation (mydriasis) without affecting the accommodative ability of the eye (cycloplegia) could be useful in many clinical and research contexts. Phenylephrine hydrochloride (PHCl) is a sympathomimetic agent that is used clinically to dilate the pupil. Nevertheless, first investigations suggested some loss of functional accommodation in the human eye after PHCl instillation. Subsequent studies, based on different measurement procedures, obtained contradictory conclusions, causing therefore an unexpected controversy that has been spread almost to the present days. This manuscript reviews and summarizes the main research studies that have been performed to analyze the effect of PHCl on the accommodative system and provides clear conclusions that could help clinicians know the real effects of PHCl on the accommodative system of the human eye.

scholarly journals Image quality eigenfunctions for the human eye

2019 ◽  
Vol 10 (11) ◽  
pp. 5818
Author(s):  
Pablo Rodríguez ◽  
Rafael Navarro ◽  
Jos J. Rozema
Keyword(s):  
Image Quality ◽  
Human Eye

Retinal image quality in the rodent eye

1998 ◽  
Vol 15 (4) ◽  
pp. 597-605 ◽  
Author(s):  
PABLO ARTAL ◽  
PILAR HERREROS de TEJADA ◽  
CARMEN MUÑOZ TEDÓ ◽  
DANIEL G. GREEN
Keyword(s):  
Image Quality ◽  
Retinal Image ◽  
Ccd Camera ◽  
Retinal Images ◽  
Modulation Transfer ◽  
Double Pass ◽  
Human Eye ◽  
Sensitivity Functions ◽  
Upper Limit ◽  
Rats And Mice

Many rodents do not see well. For a target to be resolved by a rat or a mouse, it must subtend a visual angle of a degree or more. It is commonly assumed that this poor spatial resolving capacity is due to neural rather than optical limitations, but the quality of the retinal image has not been well characterized in these animals. We have modified a double-pass apparatus, initially designed for the human eye, so it could be used with rodents to measure the modulation transfer function (MTF) of the eye's optics. That is, the double-pass retinal image of a monochromatic (λ = 632.8 nm) point source was digitized with a CCD camera. From these double-pass measurements, the single-pass MTF was computed under a variety of conditions of focus and with different pupil sizes. Even with the eye in best focus, the image quality in both rats and mice is exceedingly poor. With a 1-mm pupil, for example, the MTF in the rat had an upper limit of about 2.5 cycles/deg, rather than the 28 cycles/deg one would obtain if the eye were a diffraction-limited system. These images are about 10 times worse than the comparable retinal images in the human eye. Using our measurements of the optics and the published behavioral and electrophysiological contrast sensitivity functions (CSFs) of rats, we have calculated the CSF that the rat would have if it had perfect rather than poor optics. We find, interestingly, that diffraction-limited optics would produce only slight improvement overall. That is, in spite of retinal images which are of very low quality, the upper limit of visual resolution in rodents is neurally determined. Rats and mice seem to have eyes in which the optics and retina/brain are well matched.

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