Macroanatomic, light and scanning electron microscopic structure of the pecten oculi in northern bald ibis...

Eyes are the most primarily required sensory organs during the migration of migratory birds and Northern Bald Ibises (Geronticus eremita) are known to make long migrations. This study examined for the first time the structure of pecten oculi in northern bald ibises by using macroscopic anatomy as well as light and electron microscopic methods. In the study 20 eye globes from 10 adult bald ibises were used. The pecten was of pleated type. As in most bird species, it was located on the optic nerve head and projects into the vitreous from the optic nerve head. The wider basal part was observed to attached to retina and its free apical part was found in camera vitrea bulbi embedded in corpus vitreum. The pecten had 13-14 accordion like pleats lying between the basal and apical parts. In addition to arterial and venous vessels, numerous capillary vessels as well as melanocytes were observed within each pleat. The bridge binding the pleats at the apical part showed a stronger pigmentation compared to other parts of the pecten. The results of the study indicated that the general morphology of pecten oculi in northern bald ibises which is a migratory bird species were similar to that in other diurnal bird species.