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Dick Dubielzig Carmen Colitz Judy St Leger

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

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Dick Dubielzig Carmen Colitz Judy St Leger

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  1. Morphology of the Normal eye of the California Sea Lion (Zalophus californianus) with Attention to Accommodation Dick Dubielzig Carmen Colitz Judy St Leger

  2. 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

  3. Size of the Eye Elephant Seal 6.2cm x 4.46 cm California Sea Lion 4.94cm x 3.64 cm

  4. Adaptations for underwater vision - The round lens

  5. Adaptations for vision out of water Pinpoint pupil Flattened corneal surface

  6. 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

  7. Morphologic Features

  8. Morphologic Features 1 2 3 4 5

  9. Morphologic Features

  10. Morphologic Features

  11. Contact Between the Ciliary Pars Plicata and the Lens Capsule

  12. Regulation of Pupil Size • Pupil size increases in water in dim light but not on land (Schusterman) • Since the dilator muscle is rudimentary, might this represent a forward movement of the lens in water? http://www.ucsc.edu/oncampus/currents/97-08-18/seal.htm

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