Topography of ganglion cells in the retina of the duck (Anas platyrhynchos var. domesticus)

Abstract

ABSTRACTThe purpose of this study was to define ganglion cell density, size and topography in the retina of the mallard duck. After killing adult mallard ducks (Anas platyrhynchos var. domesticus), their eyes were removed using pentobarbital (30 mg/kg). The retinas were isolated, whole mount specimens were prepared by staining with 0.1% cresyl violet and then fixing the tissues for study. The retinal ganglion cells were counted, mapped and measured. The mean total number of ganglion cells was estimated at approximately 1.7 × 106 and the retinal area centralis had the highest ganglion cell density with 15 820 cells/mm2. The number of ganglion cell bodies was highest in the temporal area, followed by the nasal, dorsal and ventral areas. Ganglion cell size ranged from 56 to 406 μm2. A population of small ganglion cells persisted into the central area just above the optic disc and the largest soma area was in the ventral zone of the retina. This localization of ganglion cells suggests that the quality of vision is not equal in all the areas of the duck retina and the central part may have the highest vision quality as a function of the retinal ganglion cells.