Vision of the Humboldt penguin (Spheniscus humboldti) in air and water

@article{Sivak1987VisionOT,
  title={Vision of the Humboldt penguin (Spheniscus humboldti) in air and water},
  author={J. G. Sivak and Howard C. Howland and Patricia McGill-Harelstad},
  journal={Proceedings of the Royal Society of London. Series B. Biological Sciences},
  year={1987},
  volume={229},
  pages={467 - 472}
}
Refractive states measured by retinoscopy and photorefraction indicate that the eyes of the Humboldt penguin, Spheniscus humboldti, are approximately emmetropic in air and water. Extensive myopia in air, as predicted by earlier authors and by a recent anatomical study, is non-existent. Photorefractive measurements of the refractive state, in water, of the Humboldt penguin indicate that it can accommodate sufficiently to make up the loss of the refractive power of the cornea. The cornea of the… 

Figures and Tables from this paper

The eye of the magellanic penguin (Spheniscus magellanicus): structure of the anterior segment.

The anatomical peculiarities of the eyeball shape in Sphenisciformes are accompanied by several modifications in the organization of the anterior segment of the eye, which is probably relevant for the adaptation of penguin eyes to vision on land and in the aquatic environment.

Functional morphology of the cornea of the Little Penguin Eudyptula minor (Aves)

The first description of the ultrastructure of all of the main components of the cornea in two different‐sized individuals of the Little Penguin Eudyptula minor reveals a range of functional adaptations that reflect the amphibious lifestyle of this seabird.

Corneal power and underwater accommodation in great cormorants (Phalacrocorax carbo sinensis)

The results support previously reported capacities of lenticular changes in amphibious birds yet do not fully correspond with earlier reports in terms of the coupling of iris constriction with accommodation, and time course.

Determination of Tear Production and Intraocular Pressure With Rebound Tonometry in Wild Humboldt Penguins (Spheniscus humboldti)

Tear production in penguins differed between beach and sex, whereas IOP differed between age, year, and beach, and the IOPs were negatively correlated with packed cell volume.

Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

An interdependence between IOP and aqueous flow rate crucial to ocular function is highlighted that must be considered to understand the evolution of the dioptric apparatus and should be taken into consideration in the prevention and treatment of glaucoma.

Environmental adaptations in the retina of the Magellanic Penguin: Photoreceptors and outer plexiform layer

The structure of the outer plexiform layer suggests that the penguin retina would be adapted to the extreme changes in illumination and contrast conditions encountered by diving penguins.

Ocular Bacterial Flora, Tear Production, and Intraocular Pressure in a Captive Flock of Humboldt Penguins (Spheniscus humboldti)

  • R. L. SwingerJ. LanganR. Hamor
  • Medicine
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians
  • 2009
To determine normal ocular surface bacterial flora, tear production, and intraocular pressure in a captive flock of Humboldt penguins, Spheniscus humboldti, this data should be utilized as a reliable resource for those involved in avian and zoo medicine.

The Visual Ecology of Avian Photoreceptors

  • N. Hart
  • Biology
    Progress in Retinal and Eye Research
  • 2001

Visual accommodation and active pursuit of prey underwater in a plunge-diving bird: the Australasian gannet

This work presents the first demonstration of the capacity for visual accommodation underwater in a plunge diving bird while capturing submerged prey detected from the air, and analyses underwater video footage for evidence that gannets use vision in the aquatic phases of hunting.

References

SHOWING 1-9 OF 9 REFERENCES

The eye of the humboldt penguin, Spheniscus humboldti: visual fields and schematic optics

Construction of a schematic eye indicates that the eye of Spheniscus humboldti is aquatic in design and minimum pupil size would seem insufficient to allow the pupil to function as a stenopaic aperture and increase depth of focus sufficiently to overcome the eye’s aerial myopia.

The role of a flat cornea in the amphibious behaviour of the blackfoot penguin (Spheniscus demersus)

Study of corneal curvature and pupil response indicates that a mechanism of compensation for amphibious activity involving a split aperture is not present, and it is suggested that the hyperopia that persists in water may be lessened through accommodation or as a result of the spectral quality of the aquatic environment.

The anatomy of the eye of the Adélie penguin with special reference to optical structure and intraocular musculature

Study of the gross anatomy of the eye of the Adelie penguin supports the optical results; the cornea is small in diameter and it has an abnormally large radius of curvature, and Histological study of the intraocular muscles indicates that an accommodative mechanism can compensate for refractive losses in water.

Photorefraction: a technique for study of refractive state at a distance.

The technique provides an objective method for estimating the refractive states of both eyes of a subject simultaneously, under more-or-less-natural circumstances, and may find practical application in the visual screening of very young children.

Optics of photorefraction: orthogonal and isotropic methods.

Analysis of the optics of photorefractively computed ray tracing shows that, for short camera-to-subject distances, the function relating image size to defocus of the eye is not symmetrical for

A simple photokeratoscope.

  • J. Sivak
  • Medicine
    American journal of optometry and physiological optics
  • 1977

Penguin vision in air and water