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Multifocal optical systems and pupil dynamics in birds.

Lind, Olle LU ; Kelber, Almut LU and Kröger, Ronald LU (2008) In Journal of Experimental Biology 211(Pt 17). p.2752-2758
Abstract
In animal eyes of the camera type longitudinal chromatic aberration causes defocus that is particularly severe in species with short depth of focus. In a variety of vertebrates, multifocal optical systems compensate for longitudinal chromatic aberration by concentric zones of different refractive powers. Since a constricting circular pupil blocks peripheral zones, eyes with multifocal optical systems often have slit pupils that allow light to pass through all zones, irrespective of the state of pupil constriction. Birds have circular pupils and were therefore assumed to have monofocal optical systems. We examined the eyes of 45 species (12 orders) of bird using videorefractometry, and the results are surprising: 29 species (10 orders) have... (More)
In animal eyes of the camera type longitudinal chromatic aberration causes defocus that is particularly severe in species with short depth of focus. In a variety of vertebrates, multifocal optical systems compensate for longitudinal chromatic aberration by concentric zones of different refractive powers. Since a constricting circular pupil blocks peripheral zones, eyes with multifocal optical systems often have slit pupils that allow light to pass through all zones, irrespective of the state of pupil constriction. Birds have circular pupils and were therefore assumed to have monofocal optical systems. We examined the eyes of 45 species (12 orders) of bird using videorefractometry, and the results are surprising: 29 species (10 orders) have multifocal systems, and only five species (five orders) have monofocal systems. The results from 11 species (four orders) are inconclusive. We propose that pupils ;switching' between being fully opened (multifocal principle) to maximally closed (pinhole principle) can make multifocal optical systems useful for animals with circular pupils. Previous results indicate that mice have both multifocal optical systems and switching pupils. Our results suggest that parrots may use a similar mechanism. By contrast, owl pupils responded weakly to changes in illumination and stayed remarkably wide even in full daylight. Moreover, the parrots opened their pupils at higher light levels than owls, which correlates with the differences in sensitivity between diurnal and nocturnal eyes. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Experimental Biology
volume
211
issue
Pt 17
pages
2752 - 2758
publisher
The Company of Biologists Ltd
external identifiers
  • wos:000258665700012
  • pmid:18723531
  • scopus:53949094557
ISSN
1477-9145
DOI
10.1242/jeb.018630
language
English
LU publication?
yes
id
9bc8d1d4-50a7-438c-9263-3b9b97d30a76 (old id 1222960)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/18723531?dopt=Abstract
date added to LUP
2008-09-03 12:22:53
date last changed
2017-05-21 03:33:08
@article{9bc8d1d4-50a7-438c-9263-3b9b97d30a76,
  abstract     = {In animal eyes of the camera type longitudinal chromatic aberration causes defocus that is particularly severe in species with short depth of focus. In a variety of vertebrates, multifocal optical systems compensate for longitudinal chromatic aberration by concentric zones of different refractive powers. Since a constricting circular pupil blocks peripheral zones, eyes with multifocal optical systems often have slit pupils that allow light to pass through all zones, irrespective of the state of pupil constriction. Birds have circular pupils and were therefore assumed to have monofocal optical systems. We examined the eyes of 45 species (12 orders) of bird using videorefractometry, and the results are surprising: 29 species (10 orders) have multifocal systems, and only five species (five orders) have monofocal systems. The results from 11 species (four orders) are inconclusive. We propose that pupils ;switching' between being fully opened (multifocal principle) to maximally closed (pinhole principle) can make multifocal optical systems useful for animals with circular pupils. Previous results indicate that mice have both multifocal optical systems and switching pupils. Our results suggest that parrots may use a similar mechanism. By contrast, owl pupils responded weakly to changes in illumination and stayed remarkably wide even in full daylight. Moreover, the parrots opened their pupils at higher light levels than owls, which correlates with the differences in sensitivity between diurnal and nocturnal eyes.},
  author       = {Lind, Olle and Kelber, Almut and Kröger, Ronald},
  issn         = {1477-9145},
  language     = {eng},
  number       = {Pt 17},
  pages        = {2752--2758},
  publisher    = {The Company of Biologists Ltd},
  series       = {Journal of Experimental Biology},
  title        = {Multifocal optical systems and pupil dynamics in birds.},
  url          = {http://dx.doi.org/10.1242/jeb.018630},
  volume       = {211},
  year         = {2008},
}