morphology of the normal eye of the california sea lion (zalophus californianus) with attention to...
TRANSCRIPT
Morphology of the Normal eye of the California Sea Lion (Zalophus californianus) with Attention to Accommodation
Dick Dubielzig
Carmen Colitz
Judy St Leger
Pinniped Vision• Evolutionary offshoot of the carivora
– Holangiotic retina– Canine-like tapetum
• Adaptations for underwater vision– Relatively round lens
• Adaptations for vision out of water– Small pupillary aperture – Relatively flat corneal curvature
• Accommodation • Adaptations for vision in dim light at great depths
– Tapetum covers an extensive portion of the fundus– Mechanisms for pupil dilation
Pinniped vision and AccommodationReview of the literature
• Schusterman et.al, Why Pinnipeds don’t echolocate J Accust Soc Am 2000– No echolocation
• Hanke et.al., Corneal topography, refractive state, and accomodation in Harbor Seals (Phaco vitulina) Vision Research 2006– Flattened corneal plateau– Myopia and astigmatism in air and emmotropia and no astigmatism in
water
• West et.al. (Murphy), A comparative study of the anatomy of the iris and ciliary body in aquatic mammals. Can J Zool 1991– Documents the arrangement and orientation of the iris and ciliary muscles
in pinnipeds