Saccadic oscillations facilitate ocular perfusion from the avian pecten

  title={Saccadic oscillations facilitate ocular perfusion from the avian pecten},
  author={John D. Pettigrew and Josh Wallman and Christine F. Wildsoet},
THE evolution of the eye is constrained by two conflicting requirements—good vascular perfusion of the retina, and an optical path through the retina that is unobstructed by blood vessels. Birds are interesting in that they have higher metabolic rates and thicker retinas than mammals, but have no retinal blood vessels. Nutrients and oxygen must thus reach the neurons of the inner retina either from the choroid through 300 μm of metabolically very active retina, or from the pecten, a pleated… 
Feeding the vertebrate retina from the Cambrian to the Tertiary
This work reviews classical and recent findings regarding retinal nutrition systems, proposes a three category classification for them based on histologic origins and speculate on the evolutionary forces which drove their development.
Retinal metabolism: A comparative look at energetics in the retina
Low oxygen consumption in the inner retina of the visual streak of the rabbit.
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  • Medicine, Biology
    American journal of physiology. Heart and circulatory physiology
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The first measurements ofretinal oxygen consumption in the visual streak of the rabbit retina, the region with the highest density of retinal neurons, are reported, suggesting that the oxygen uptake of the inner retina is regulated to a large degree by the available oxygen supply rather than the processing requirements of theinner retina alone.
Oxygen Supply from the Bird's Eye Perspective
It is shown that the photoreceptor cells of the chicken retina have a high level of GbE protein, which accumulates to ∼10 μm in the total eye, and quantitative real-time RT-PCR revealed an ∼50,000-fold higher level ofGbE mRNA in the eye than in the brain.
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This study has addressed the coping strategies of those retinae which lack intraretinal blood vessels and suggested that mitochondrial numbers may be reduced within the inner retinal layers of avascular retinae when compared with similar regions in vascular retinae.
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Surface specialization of the capillary endothelium in the pecten oculi of the chicken, and their overt roles in pectineal haemodynamics and nutrient transfer to the inner neural retina.
The apparent set-up of the luminal plasmalemmal infoldings seemed to be designed for effecting impedance to the pectineal blood flow and thereby facilitating passive permeation of blood-borne nutrients to the inner neural retina.


Pecten of the pigeon's eye as an inter-ocular eye shade.
The primary shadow of the pecten 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.
A light and electron microscopic study of the pecten of the pigeon eye.
The pecten in the pigeon is a pleated lamina that consists of blood vessels and interstitial pigment cells that are sandwiched between two basement laminae and separate the blood vessels from the vitreous body.
Electron microscopic observations on the pecten of the nighthawk (Chordeiles minor).
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The pecten of a nocturnally active bird, the nighthawk (Chordeiles minor) has been examined by light and electron microscopy and is indicative of a heavy involvement in the transport of materials.
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Rapid serial fundus angiography on four species of birds pictorially documented avian pecten permeability to intravenously injected sodium fluorescein. Possible mechanisms and implications of this
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In addition to its well-accepted nutritive role, I propose a function for the pecten that is a synthesis of the views of Griffin (that it might play a role in migration), Menner (that it casts a