Pecten oculi

The pecten or pecten oculi is a comb-like structure of blood vessels belonging to the choroid in the eye of a bird. It is a non-sensory, pigmented structure that projects into the vitreous body from the point where the optic nerve enters the eyeball. The pecten is believed to both nourish the retina and control the pH of the vitreous body. High level of enzyme alkaline phosphatase activity in pecten oculi, has been linked to transport of nutrient molecules from highly vascularized pecten oculi into vitreous and then into retinal cells for nourishment. It is present in all birds and some reptiles.