Visual fields and eye movements in a harbor seal (Phoca vitulina).
The boundaries of the visual fields of a harbor seal were measured using static perimetry. In the seal lying on a plane surface (fixation point "0 degrees" straight ahead at eye-level), the visual field with fixed eyes extended over 208 degrees horizontally and reached from -12 degrees to +69 degrees vertically. The binocular visual field amounted to 67 degrees. Eye movements of 12 degrees (+/-2) degrees to both sides and 64 degrees upwards could be induced. In the seal performing eye movements, a visual field of 210 degrees in the horizontal plane and 121 degrees to the dorsal side was determined. From the measured eye movements, a visual field of 232 degrees in the horizontal plane appears possible.
Hanke
Wolf
W
University of Bochum, General Zoology and Neurobiology, ND 6/33, D-44780 Bochum, Germany.
Römer
Raffaela
R
Dehnhardt
Guido
G
D000818:Animals; D005133:Eye Movements / Q000502:physiology*; D005403:Fixation, Ocular / Q000502:physiology; D046049:Phoca / Q000502:physiology*; D011594:Psychometrics; D015348:Vision, Binocular / Q000502:physiology; D015349:Vision, Monocular / Q000502:physiology; D058609:Visual Field Tests / Q000379:methods; D014794:Visual Fields / Q000502:physiology*