Abstract
THE eyes Of all birds have a black pleated structure, known as the pecten, which projects from the retinal surface into the vitreal space, towards the lens. This remarkable structure has provoked many speculations about its function1,2, but only one has so far been widely accepted : the pecten has a copious blood supply and this is thought to function as a replacement for the capillary bed that, in many other vertebrates, supplies the vitreal surface of the retina3,4. Its size, shape, and heavy black pigmentation have suggested optical functions, some of which centre around its shadow casting potentialities5,6, but many of these theories do not seem to take account of the way the pecten is placed in the optical system. It is oriented nearly parallel to light entering the centre of the pupil, so that it presents the minimum area to the converging rays forming the retinal image, and the folded free border that is its most striking gross anatomical feature approaches close behind the lens. Thus the shadow cast by the incoming light, which we here call the “primary shadow”, will be as small as possible and very blurred. It is, furthermore, centred on the pecten's own base, which is the elongated optic disk or “blind spot”, devoid of receptors, where optic nerve fibres leave the eye. Thus we think the primary shadow has no beneficial functional significance; on the contrary, it is remarkable that such a large nutrient structure can be inserted into a small optical system with so little disturbance to its normal image forming function. There is, however, an optical function that can be performed by an opaque screen in the position of the pecten.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Head-tracking of freely-behaving pigeons in a motion-capture system reveals the selective use of visual field regions
Scientific Reports Open Access 09 November 2022
Access options
Subscribe to this journal
We are sorry, but there is no personal subscription option available for your country.
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
References
Walls, G., The Vertebrate Eye and Its Adaptive Radiation (Cranbrook Institute of Science, Bulletin No. 19, 1942; and Dover Reprint).
Wingstrand, K., and Munk, O., Biologiske Skriften, 14, 1 (1965).
O'Rahilly, R., and Meyer, D. B., in The Structure of the Eye (edit. by Smelser) (Academic Press, New York, 1961).
Raviola, E., and Raviola, G., Amer. J. Anat., 120, 427 (1967).
Menner, E., Zool. Jahrb., Abt. Allg. Zool. Physiol. Tiere, 58, 481 (1938).
Crozier, W. J., and Wolf, E., J. Gen. Physiol., 27, 387 (1943); ibid., 315 (1943).
Vos, J. J., J. Opt. Soc. Amer., 53, 1449 (1963).
Vos, J. J., and Bouman, M. A., J. Opt. Soc. Amer., 54, 95 (1964).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
BARLOW, H., OSTWALD, T. Pecten of the Pigeon's Eye as an Inter-ocular Eye Shade. Nature New Biology 236, 88–90 (1972). https://doi.org/10.1038/newbio236088a0
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1038/newbio236088a0
This article is cited by
-
Head-tracking of freely-behaving pigeons in a motion-capture system reveals the selective use of visual field regions
Scientific Reports (2022)
-
Ontogeny of the conus papillaris of the lizard Gallotia galloti and cellular response following transection of the optic nerve: an immunohistochemical and ultrastructural study
Cell and Tissue Research (2011)