Table 3.

Optical parameters and performance of avian species*

Common name
Species nameSourceCorneaAccommodationPupil constriction†
Black guillemot Sivak et al., 1978  Radius: NA RS: Air=0 D, Water=+5.0 D. NA 
Cepphus grylle  Power: NA Methods: retinoscope, forced submergence.  
  Effective index: 1.370 N=6 birds.  
Common goldeneye Sivak et al., 1985  Radius: NA Range: 66.8 D, peaks in approx. 0.4 s. 4→3.4 
Bucephala clangula  Power:74.5‡ Methods: electric elicitation of iris.  
  Effective index: NA N=1 bird.  
Great cormorant Present study Radius: 6.7-5.4 RS: Air=+0.45 D; Water=-1.79 D. Not apparent 
Phalacrocorax carbo sinensis  Power: 50.1-61.8 Range: 64 D.  
  Effective index: NA Methods: voluntary dives. N=7 birds.  
Double crested cormorant Sivak et al., 1977  Mean radius: 9.3 RS: Air=0 D; Water=+3.0 D to +36.0 D. NA 
Phalacrocorax auritus  Mean power:34.8‡ Methods: retinoscopy, forced submergence.  
  Effective index: 1.37 Anaesthetized underwater. N=3 birds.  
 Sivak et al., 1978  Radius: NA RS: Air=0 D, Water=+3.0 D. NA 
  Power: NA Methods: forced submergence.  
  Effective index: 1.371 N=2 birds.  
Dipper Goodge, 1960  Radius: NA RS: Air:=-2.0 D to +1.5 D; Water=+40 D to +44 D; induced: 46-48 D. NA 
Cinclus mexicanus  Power: NA   
  Effective index: NA Methods: forced submergence. N=2 eyes.  
Hooded merganser Levy and Sivak, 1980  Radius: NA RS: Air=0 D; induced=50 D. 3→1 
Mergus cucullatus  Power: NA Methods: nicotine sulfate, excised eyes. In tens of seconds 
  Effective index: NA N=4 eyes.  
 Sivak et al., 1978  Radius: NA RS: Air=+1.25 D; Water=+7.0 D.  
  Power: NA   
  Effective index: NA   
 Sivak et al., 1985  Radius: NA Range 78.3 D; peaks in approx. 0.5 s. 3.8→3.1 
  Power:78.5‡ Methods: electric stimulation of iris. 4.6→3.9 
  Effective index: NA N=4 eyes. 3.9→3.2 
Mallard Levy and Sivak, 1980  Radius: NA RS: Air=+1.0 D; induced -5 D.  
Anas plathyrhynchos  Power: NA N=8 eyes.  
  Effective index: 1.373   
 Sivak et al., 1978  Radius: NA RS: Air=0 D; Water=45.0 D. Unpublished data 
  Power: NA N=2 birds.  
  Effective index: 1.373   
 Sivak et al., 1985  Radius: NA Range 2.7 D. 4.7→3 
  Power:76.5‡ Methods: electric elicitation of iris.  
  Effective index: 1.375 N=2 birds.  
Red headed duck Levy and Sivak, 1980  Radius: NA RS: Air=0 D; induced 50 D. 5→1 
Aythya americana  Power: NA Methods: nicotine sulfate on excised eyes. In minutes 
  Effective index: NA N=4 eyes.  
 Sivak et al., 1985  Radius: NA Range 16 D; peaks in 0.15 s. 2.9→2.3 
  Power:83‡ Methods: electric elicitation of iris.  
  Effective index: NA N=1 bird.  
Wood duck Sivak et al., 1985  Radius: NA Range 6.5 D; peaks in 0.3 s. 4→2.7 
Aix sponsa  Power:74.5‡ Methods: electric elicitation of iris.  
  Effective index: NA N=1 bird.  
Gray headed albatross Martin, 1998  Radius: 14.5 NA NA 
Diomedea chrysostoma  Power: 23   
  Effective index: NA   
Common name
Species nameSourceCorneaAccommodationPupil constriction†
Black guillemot Sivak et al., 1978  Radius: NA RS: Air=0 D, Water=+5.0 D. NA 
Cepphus grylle  Power: NA Methods: retinoscope, forced submergence.  
  Effective index: 1.370 N=6 birds.  
Common goldeneye Sivak et al., 1985  Radius: NA Range: 66.8 D, peaks in approx. 0.4 s. 4→3.4 
Bucephala clangula  Power:74.5‡ Methods: electric elicitation of iris.  
  Effective index: NA N=1 bird.  
Great cormorant Present study Radius: 6.7-5.4 RS: Air=+0.45 D; Water=-1.79 D. Not apparent 
Phalacrocorax carbo sinensis  Power: 50.1-61.8 Range: 64 D.  
  Effective index: NA Methods: voluntary dives. N=7 birds.  
Double crested cormorant Sivak et al., 1977  Mean radius: 9.3 RS: Air=0 D; Water=+3.0 D to +36.0 D. NA 
Phalacrocorax auritus  Mean power:34.8‡ Methods: retinoscopy, forced submergence.  
  Effective index: 1.37 Anaesthetized underwater. N=3 birds.  
 Sivak et al., 1978  Radius: NA RS: Air=0 D, Water=+3.0 D. NA 
  Power: NA Methods: forced submergence.  
  Effective index: 1.371 N=2 birds.  
Dipper Goodge, 1960  Radius: NA RS: Air:=-2.0 D to +1.5 D; Water=+40 D to +44 D; induced: 46-48 D. NA 
Cinclus mexicanus  Power: NA   
  Effective index: NA Methods: forced submergence. N=2 eyes.  
Hooded merganser Levy and Sivak, 1980  Radius: NA RS: Air=0 D; induced=50 D. 3→1 
Mergus cucullatus  Power: NA Methods: nicotine sulfate, excised eyes. In tens of seconds 
  Effective index: NA N=4 eyes.  
 Sivak et al., 1978  Radius: NA RS: Air=+1.25 D; Water=+7.0 D.  
  Power: NA   
  Effective index: NA   
 Sivak et al., 1985  Radius: NA Range 78.3 D; peaks in approx. 0.5 s. 3.8→3.1 
  Power:78.5‡ Methods: electric stimulation of iris. 4.6→3.9 
  Effective index: NA N=4 eyes. 3.9→3.2 
Mallard Levy and Sivak, 1980  Radius: NA RS: Air=+1.0 D; induced -5 D.  
Anas plathyrhynchos  Power: NA N=8 eyes.  
  Effective index: 1.373   
 Sivak et al., 1978  Radius: NA RS: Air=0 D; Water=45.0 D. Unpublished data 
  Power: NA N=2 birds.  
  Effective index: 1.373   
 Sivak et al., 1985  Radius: NA Range 2.7 D. 4.7→3 
  Power:76.5‡ Methods: electric elicitation of iris.  
  Effective index: 1.375 N=2 birds.  
Red headed duck Levy and Sivak, 1980  Radius: NA RS: Air=0 D; induced 50 D. 5→1 
Aythya americana  Power: NA Methods: nicotine sulfate on excised eyes. In minutes 
  Effective index: NA N=4 eyes.  
 Sivak et al., 1985  Radius: NA Range 16 D; peaks in 0.15 s. 2.9→2.3 
  Power:83‡ Methods: electric elicitation of iris.  
  Effective index: NA N=1 bird.  
Wood duck Sivak et al., 1985  Radius: NA Range 6.5 D; peaks in 0.3 s. 4→2.7 
Aix sponsa  Power:74.5‡ Methods: electric elicitation of iris.  
  Effective index: NA N=1 bird.  
Gray headed albatross Martin, 1998  Radius: 14.5 NA NA 
Diomedea chrysostoma  Power: 23   
  Effective index: NA   
*

Data exclude those of penguins.

†

Pupil constriction (mm) is during accommodation. RS, refractive state; NA,data not available.

‡

Corneal power (measured in diopters) was calculated as F=337.5/R, where R (measured in mm) is corneal radius. Effective corneal refractive index was measured in meters.

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