Unique Architecture and Ultrastructure of the Raptor Eye

The raptor eye is specially adapted in both the gross architecture and ultrastructure for visual acuity, day/night vision and flight navigation. For this study a correlative approach utilizing light, fluorescence and scanning electron microscopy was used to investigate specific structures of the eye of Buteo jamaicensis (red-tailed hawk). The structure of the pecten oculi and retina were examined as to how their unique form contributes to the specific function of the eye . The pecten is a structure that most birds possess with a function that is not clearly defined. It is a heavily pigmented, highly vascular, pleated structure that protrudes into the vitreous humor from the retina and obscures the optic disc. The retina is unique in that the bifoveate nature allows focusing on multiple planes simultaneously, an adaptation for avoiding collisions while in pursuit of prey. The retina also includes a highly adapted pigmented epithelial layer that functionally extends and retracts into the photoreceptor layer to reduce flare.