Depth of focus, eye size and visual acuity

Green, Daniel G.; Powers, Maureen K.; Banks, Martin S.

doi:10.1016/0042-6989(80)90063-2

Cited by 211 publications

(108 citation statements)

References 45 publications

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“…Distant stimuli at lower elevations could be viewed in focus most simply by tilting the head. Green, Powers & Banks (1980) have estimated with Gaussian optical approximations that the 'depth of focus' of the pigeon eye is 0-3 D. In peripheral viewing the elliptical shape of the pupil will confer a meridional variation both to resolution and to depth of focus. Depth of focus will be least different from that in axial viewing where a grating is orthogonal to the long axis of the pupil.…”

Section: Discussionmentioning

confidence: 99%

Refractive sectors in the visual field of the pigeon eye.

Fitzke¹,

Hayes²,

Hodos³

et al. 1985

The Journal of Physiology

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Scheiner's principle has been used in electroretinographic optometry to refract the photoreceptor plane in different regions of the visual field of the pigeon eye. Along the horizon and in the upper visual field the eye is emmetropic, or nearly so. Below the horizon the eye becomes progressively more myopic at more negative elevations, refractive state falling to ‐5D at ‐90 deg. Lower field myopia is not an artifact of oblique astigmatism, nor of an aberration symmetrical about the optical axis. It is suggested that lower field myopia is a biological adaptation suited to keep the photoreceptors in the upper retina conjugate with the ground. Refractive state below the horizon can be fitted with a sine function by varying a parameter H (eye‐ground height). The value of H agrees well with directly measured eye‐ground height.

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Section: Discussionmentioning

confidence: 99%

Refractive sectors in the visual field of the pigeon eye.

Fitzke¹,

Hayes²,

Hodos³

et al. 1985

The Journal of Physiology

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“…After nine sessions, all animals were still responding at chance (50% or below) accuracy. In light of reports by Dean (1981) and Green, Powers, and Banks (1980), whose assessments of rats' visual acuity indicated that rats should be at least 20 cm from visual stimuli to achieve accurate visual discrimination, we reasoned that increasing the animals' distance from the video screen at the beginning of trials might improve performance. Accordingly, after Session 9, the chamber was modified by moving the food magazine and pellet dispenser so that pellets were delivered at the center of the rear chamber wall (see Figure IB).…”

mentioning

confidence: 99%

A Computer Touch‐screen Apparatus for Training Visual Discriminations in Rats

Markham

Butt

Dougher

1996

J Exper Analysis Behavior

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We describe an operant conditioning apparatus that uses computerized touch-screen technology and is designed for the versatile and highly controlled testing of rats in a potentially wide variety of behavioral paradigms. Although computer-controlled touch-screen systems have been developed for use with pigeons, monkeys, and humans, analogous technologies and methods have not yet been developed for rats. The development of a touch-screen system for rats could enhance the efficiency of behavioral research with rats, and may offer a unique tool for studying animal learning. In the first test of the utility of the apparatus, 3 Sprague-Dawley rats learned to activate the touch screen only after the touch-screen panel was made slightly movable. These animals then learned to discriminate visual stimuli presented on the computer monitor, but only after the food magazine and pellet dispenser were moved to the rear of the chamber opposite the stimulus display and response window. In a test of the utility of the modified apparatus, 6 Long-Evans rats learned to activate the touch screen and learned one of three different simple discriminations using computer-generated, visually presented stimuli. A basic method for training rats to activate the computer touch screen and for visual discrimination training is described. Results show that rats learned to activate the touch screen and discriminate visual stimuli presented on a computer monitor. Potential applications and advantages of the touch-screen-equipped rat operant conditioning chamber are discussed.

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“…Although the actual magnitude of longitudinal chromatic aberration does not necessarily scale with eye size across species [55], its effects on image quality are theoretically worse in larger eyes (especially where the pupil is large relative to the focal length, i.e. a low f-number) as they have a shorter depth of focus (by virtue of their longer focal length) compared with small eyes [57].…”

Section: Discussionmentioning

confidence: 99%

Visual pigments in a palaeognath bird, the emuDromaius novaehollandiae: implications for spectral sensitivity and the origin of ultraviolet vision

et al. 2016

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A comprehensive description of the spectral characteristics of retinal photoreceptors in palaeognaths is lacking. Moreover, controversy exists with respect to the spectral sensitivity of the short-wavelength-sensitive-1 (SWS1) opsin-based visual pigment expressed in one type of single cone: previous microspectrophotometric (MSP) measurements in the ostrich (Struthio camelus) suggested a violet-sensitive (VS) SWS1 pigment, but all palaeognath SWS1 opsin sequences obtained to date (including the ostrich) imply that the visual pigment is ultraviolet-sensitive (UVS). In this study, MSP was used to measure the spectral properties of visual pigments and oil droplets in the retinal photoreceptors of the emu (Dromaius novaehollandiae). Results show that the emu resembles most other bird species in possessing four spectrally distinct single cones, as well as double cones and rods. Four cone and a single rod opsin are expressed, each an orthologue of a previously identified pigment. The SWS1 pigment is clearly UVS (wavelength of maximum absorbance [l max ] ¼ 376 nm), with key tuning sites (Phe86 and Cys90) consistent with other vertebrate UVS SWS1 pigments. Palaeognaths would appear, therefore, to have UVS SWS1 pigments. As they are considered to be basal in avian evolution, this suggests that UVS is the most likely ancestral state for birds. The functional significance of a dedicated UVS cone type in the emu is discussed.

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Depth of focus, eye size and visual acuity

Cited by 211 publications

References 45 publications

Refractive sectors in the visual field of the pigeon eye.

Refractive sectors in the visual field of the pigeon eye.

A Computer Touch‐screen Apparatus for Training Visual Discriminations in Rats

Visual pigments in a palaeognath bird, the emuDromaius novaehollandiae: implications for spectral sensitivity and the origin of ultraviolet vision

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