Refractive sectors in the visual field of the pigeon eye.

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.

[1]  P. W. Nye,et al.  On the functional differences between frontal and lateral visual fields of the pigeon. , 1973, Vision research.

[2]  M. Millodot,et al.  Retinoscopy and Eye Size , 1970, Science.

[3]  A C CATANIA,et al.  ON THE VISUAL ACUITY OF THE PIGEON. , 1964, Journal of the experimental analysis of behavior.

[4]  G. Martin,et al.  The retinal binocular field of the pigeon (Columba livia: English racing homer) , 1983, Vision Research.

[5]  W. Hodos,et al.  Electrophysiological optometry using Scheiner's principle in the pigeon eye. , 1985, The Journal of physiology.

[6]  M Millodot,et al.  The refractive state of the pigeon eye. , 1971, Vision research.

[7]  Martin S. Banks,et al.  Depth of focus, eye size and visual acuity , 1980, Vision Research.

[8]  R. Binggeli,et al.  The pigeon retina: Quantitative aspects of the optic nerve and ganglion cell layer , 1969, The Journal of comparative neurology.

[9]  J. Pettigrew,et al.  A neurophysiological determination of the vertical horopter in the cat and owl , 1979, The Journal of comparative neurology.