Abstract

Light rays of different wavelengths are focused at different distances when they pass through a lens (longitudinal chromatic aberration [LCA]). For animals with color vision this can pose a serious problem, because in order to perceive a sharp image the rays must be focused at the shallow plane of the photoreceptor’s outer segments in the retina. A variety of fish and tetrapods have been found to possess multifocal lenses, which correct for LCA by assigning concentric zones to correctly focus specific wavelengths. Each zone receives light from a specific beam entrance position (BEP) (the lateral distance between incoming light and the center of the lens). Any occlusion of incoming light at specific BEPs changes the composition of the wavelengths that are correctly focused on the retina. Here, we calculated the effect of lens position relative to the plane of the iris and light entering the eye at oblique angles on how much of the lens was involved in focusing the image on the retina (measured as the availability of BEPs). We used rotational photography of fish eyes and mathematical modeling to quantify the degree of lens occlusion. We found that, at most lens positions and viewing angles, there was a decrease of BEP availability and in some cases complete absence of some BEPs. Given the implications of these effects on image quality, we postulate that three morphological features (aphakic spaces, curvature of the iris, and intraretinal variability in spectral sensitivity) may, in part, be adaptations to mitigate the loss of spectral image quality in the periphery of the eyes of fishes.

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References

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    [Crossref]

2014 (2)

F. Busserolles, N. J. Marshall, and S. P. Collin, “The eyes of lanternfishes (myctophidae, teleostei): novel ocular specializations for vision in dim light,” J. Comp. Neurol. 522, 1618–1640 (2014).
[Crossref]

B. E. Dalton, E. R. Loew, T. W. Cronin, and K. L. Carleton, “Spectral tuning by opsin coexpression in retinal regions that view different parts of the visual field,” Proc. R. Soc. London B 281, 20141980 (2014).
[Crossref]

2013 (1)

D. Shcherbakov, A. Knörzer, S. Espenhahn, R. Hilbig, U. Haas, and M. Blum, “Sensitivity differences in fish offer near-infrared vision as an adaptable evolutionary trait,” PLoS ONE 8, e64429 (2013).
[Crossref]

2012 (1)

2011 (3)

D. J. Rennison, G. L. Owens, W. T. Allison, and J. S. Taylor, “Intra-retinal variation of opsin gene expression in the guppy (Poecilia reticulata),” J. Exp. Biol. 214, 3248–3254 (2011).
[Crossref]

Y. L. Gagnon, N. Shashar, and R. H. H. Kröger, “Adaptation in the optical properties of the crystalline lens in the eyes of the lessepsian migrant Siganus rivulatus,” J. Exp. Biol. 214, 2724–2729 (2011).
[Crossref]

S. E. Temple, “Why different regions of the retina have different spectral sensitivities: a review of mechanisms and functional significance of intraretinal variability in spectral sensitivity in vertebrates,” Visual Neurosci. 28, 281–293 (2011).
[Crossref]

2010 (4)

K. E. O’Quin, C. M. Hofmann, H. A. Hofmann, and K. L. Carleton, “Parallel evolution of opsin gene expression in African cichlid fishes,” Mol. Biol. Evol. 27, 2839–2854 (2010).
[Crossref]

S. E. Temple, N. S. Hart, N. J. Marshall, and S. P. Collin, “A spitting image: specializations in archerfish eyes for vision at the interface between air and water,” Proc. R. Soc. B 277, 2607–2615 (2010).
[Crossref]

O. S. Gustafsson, P. Ekström, and R. H. Kröger, “A fibrous membrane suspends the multifocal lens in the eyes of lampreys and African lungfishes,” J. Morphol. 271, 980–989 (2010).

J. M. Schartau, R. H. H. Kröger, and B. Sjögreen, “Short-term culturing of teleost crystalline lenses combined with high-resolution optical measurements,” Cytotechnology 62, 167–174 (2010).
[Crossref]

2009 (3)

Y. Shichida and T. Matsuyama, “Evolution of opsins and phototransduction,” Phil. Trans. R. Soc. B 364, 2881–2895 (2009).
[Crossref]

R. H. H. Kröger, K. A. Fritsches, and E. J. Warrant, “Lens optical properties in the eyes of large marine predatory teleosts,” J. Comp. Physiol. A 195, 175–182 (2009).
[Crossref]

J. M. Schartau, B. Sjögreen, Y. L. Gagnon, and R. H. H. Kröger, “Optical plasticity in the crystalline lenses of the cichlid fish Aequidens pulcher,” Curr. Biol. 19, 122–126 (2009).
[Crossref]

2008 (4)

O. S. E. Gustafsson, S. P. Collin, and R. H. H. Kröger, “Early evolution of multifocal optics for well-focused colour vision in vertebrates,” J. Exp. Biol. 211, 1559–1564 (2008).
[Crossref]

F. D. Hanke, R. H. H. Kröger, U. Siebert, and G. Dehnhardt, “Multifocal lenses in a monochromat: the harbour seal,” J. Exp. Biol. 211, 3315–3322 (2008).
[Crossref]

O. E. Lind, A. Kelber, and R. H. H. Kröger, “Multifocal optical systems and pupil dynamics in birds,” J. Exp. Biol. 211, 2752–2758 (2008).
[Crossref]

Y. L. Gagnon, B. Söderberg, and R. H. H. Kröger, “Effects of the peripheral layers on the optical properties of spherical fish lenses,” J. Opt. Soc. Am. A 25, 2468–2475 (2008).
[Crossref]

2007 (1)

B. Karpestam, J. Gustafsson, N. Shashar, G. Katzir, and R. H. H. Kröger, “Multifocal lenses in coral reef fishes,” J. Exp. Biol. 210, 2923–2931 (2007).
[Crossref]

2006 (2)

T. Malmström and R. H. H. Kröger, “Pupil shapes and lens optics in the eyes of terrestrial vertebrates,” J. Exp. Biol. 209, 18–25 (2006).
[Crossref]

J. K. Bowmaker and D. M. Hunt, “Evolution of vertebrate visual pigments,” Curr. Biol. 16, R484–R489 (2006).
[Crossref]

2005 (4)

J. W. Parry, K. L. Carleton, T. Spady, A. Carboo, D. M. Hunt, and J. K. Bowmaker, “Mix and match color vision: Tuning spectral sensitivity by differential opsin gene expression in Lake Malawi cichlids,” Curr. Biol. 15, 1734–1739 (2005).
[Crossref]

A. E. Trezise and S. P. Collin, “Opsins: evolution in waiting,” Curr. Biol. 15, R794–R796 (2005).
[Crossref]

P. E. Malkki and R. H. H. Kröger, “Visualization of chromatic correction of fish lenses by multiple focal lengths,” J. Opt. A 7, 691–700 (2005).
[Crossref]

M. Takechi and S. Kawamura, “Temporal and spatial changes in the expression pattern of multiple red and green subtype opsin genes during zebrafish development,” J. Exp. Biol. 208, 1337–1345 (2005).
[Crossref]

2004 (1)

R. H. H. Kröger and A. Gislen, “Compensation for longitudinal chromatic aberration in the eye of the firefly squid, Watasenia scintillans,” Vis. Res. 44, 2129–2134 (2004).
[Crossref]

2001 (1)

E. Loew and V. Govardovskii, “Photoreceptors and visual pigments in the red-eared turtle, Trachemys scripta elegans,” Visual Neurosci. 18, 753–757 (2001).
[Crossref]

2000 (2)

A. Koskelainen, P. Ala-Laurila, N. Fyhrquist, and K. Donner, “Measurement of thermal contribution to photoreceptor sensitivity,” Nature 403, 220–223 (2000).
[Crossref]

S. Yokoyama, “Molecular evolution of vertebrate visual pigments,” Prog. Retin. Eye Res. 19, 385–419 (2000).
[Crossref]

1999 (2)

R. H. H. Kröger, M. C. W. Campbell, R. D. Fernald, and H. J. Wagner, “Multifocal lenses compensate for chromatic defocus in vertebrate eyes,” J. Comp. Physiol. A 184, 361–369 (1999).
[Crossref]

E. J. Warrant, “Seeing better at night: life style, eye design and the optimum strategy of spatial and temporal summation,” Vis. Res. 39, 1611–1630 (1999).
[Crossref]

1996 (1)

S. S. Easter and G. N. Nicola, “The development of vision in the zebrafish (Danio rerio),” Develop. Bio. 180, 646–663 (1996).
[Crossref]

1994 (3)

J. N. Lythgoe, W. R. A. Muntz, J. C. Partridge, J. Shand, and D. M. B. Williams, “The ecology of the visual pigments of snappers (Lutjanidae) on the great barrier reef,” J. Comp. Physiol. A 174, 461–467 (1994).
[Crossref]

J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
[Crossref]

R. H. Kröger and R. D. Fernald, “Regulation of eye growth in the African cichlid fish Haplochromis burtoni,” Vis. Res. 34, 1807–1814 (1994).
[Crossref]

1992 (1)

J. Janssen, N. W. Pankhurst, and G. R. Harbison, “Swimming and body orientation of Notolepis rissoi in relation to lateral line and visual function,” J. Mar. Biol. Assoc. U.K. 72, 877–886 (1992).
[Crossref]

1991 (1)

J. K. Bowmaker, A. Thorpe, and R. H. Douglas, “UV-sensitive cones in the goldfish,” Vis. Res. 31, 349–352 (1991).
[Crossref]

1989 (3)

E. Denton and N. Locket, “Possible wavelength discrimination by multibank retinae in deep-sea fishes,” J. Mar. Biol. Assoc. U.K. 69, 409–436 (1989).
[Crossref]

N. W. Pankhurst, “The relationship of ocular morphology to feeding modes and activity periods in shallow marine teleosts from New Zealand,” Environ. Biol. Fish. 26, 201–211 (1989).
[Crossref]

S. P. Collin and J. D. Pettigrew, “Quantitative comparison of the limits on visual spatial resolution set by the ganglion cell layer in twelve species of reef teleosts,” Brain Behav. Evol. 34, 184–192 (1989).
[Crossref]

1987 (1)

J. K. Bowmaker and Y. W. Kunz, “UV receptors tetrachromatic color vision and retinal mosaics in the brown trout Salmo trutta age-dependent changes,” Vis. Res. 27, 2101–2108 (1987).
[Crossref]

1985 (1)

R. D. Fernald and S. E. Wright, “Growth of the visual system in the African cichlid fish, Haplochromis burtoni: accommodation,” Vis. Res. 25, 163–170 (1985).
[Crossref]

1981 (1)

A. Blest, R. Hardie, P. McIntyre, and D. Williams, “The spectral sensitivities of identified receptors and the function of retinal tiering in the principal eyes of a jumping spider,” J. Comp. Physiol. 145, 227–239 (1981).
[Crossref]

1978 (1)

J. G. Sivak and W. R. Bobier, “Chromatic aberration of the fish eye and its effect on refractive state,” Vis. Res. 18, 453–455 (1978).
[Crossref]

1975 (1)

J. G. Sivak, “Accommodative lens movements in fishes: movement along the pupil axis vs movement along the pupil plane,” Vis. Res. 15, 825–828 (1975).
[Crossref]

1974 (1)

O. Munk and R. D. Frederiksen, “On the function of aphakic apertures in teleosts,” Videnskabelige meddelelser fra Dansk naturhistorisk forening i København 137, 65–94 (1974).

1973 (1)

W. Charman and J. Tucker, “The optical system of the goldfish eye,” Vis. Res. 13, 1–8 (1973).
[Crossref]

1894 (1)

T. Beer, “Die accommodation des fischauges,” Pflügers Archiv Eur. J. Physiol. 58, 523–650 (1894).
[Crossref]

Ala-Laurila, P.

A. Koskelainen, P. Ala-Laurila, N. Fyhrquist, and K. Donner, “Measurement of thermal contribution to photoreceptor sensitivity,” Nature 403, 220–223 (2000).
[Crossref]

Allison, W. T.

D. J. Rennison, G. L. Owens, W. T. Allison, and J. S. Taylor, “Intra-retinal variation of opsin gene expression in the guppy (Poecilia reticulata),” J. Exp. Biol. 214, 3248–3254 (2011).
[Crossref]

Beer, T.

T. Beer, “Die accommodation des fischauges,” Pflügers Archiv Eur. J. Physiol. 58, 523–650 (1894).
[Crossref]

Bezanson, J.

J. Bezanson, A. Edelman, S. Karpinski, and V. B. Shah, “Julia: a fresh approach to numerical computing,” arXiv:1411.1607 (2014).

Blest, A.

A. Blest, R. Hardie, P. McIntyre, and D. Williams, “The spectral sensitivities of identified receptors and the function of retinal tiering in the principal eyes of a jumping spider,” J. Comp. Physiol. 145, 227–239 (1981).
[Crossref]

Blum, M.

D. Shcherbakov, A. Knörzer, S. Espenhahn, R. Hilbig, U. Haas, and M. Blum, “Sensitivity differences in fish offer near-infrared vision as an adaptable evolutionary trait,” PLoS ONE 8, e64429 (2013).
[Crossref]

Bobier, W. R.

J. G. Sivak and W. R. Bobier, “Chromatic aberration of the fish eye and its effect on refractive state,” Vis. Res. 18, 453–455 (1978).
[Crossref]

Bowmaker, J. K.

J. K. Bowmaker and D. M. Hunt, “Evolution of vertebrate visual pigments,” Curr. Biol. 16, R484–R489 (2006).
[Crossref]

J. W. Parry, K. L. Carleton, T. Spady, A. Carboo, D. M. Hunt, and J. K. Bowmaker, “Mix and match color vision: Tuning spectral sensitivity by differential opsin gene expression in Lake Malawi cichlids,” Curr. Biol. 15, 1734–1739 (2005).
[Crossref]

J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
[Crossref]

J. K. Bowmaker, A. Thorpe, and R. H. Douglas, “UV-sensitive cones in the goldfish,” Vis. Res. 31, 349–352 (1991).
[Crossref]

J. K. Bowmaker and Y. W. Kunz, “UV receptors tetrachromatic color vision and retinal mosaics in the brown trout Salmo trutta age-dependent changes,” Vis. Res. 27, 2101–2108 (1987).
[Crossref]

Busserolles, F.

F. Busserolles, N. J. Marshall, and S. P. Collin, “The eyes of lanternfishes (myctophidae, teleostei): novel ocular specializations for vision in dim light,” J. Comp. Neurol. 522, 1618–1640 (2014).
[Crossref]

Campbell, M. C. W.

R. H. H. Kröger, M. C. W. Campbell, R. D. Fernald, and H. J. Wagner, “Multifocal lenses compensate for chromatic defocus in vertebrate eyes,” J. Comp. Physiol. A 184, 361–369 (1999).
[Crossref]

Carboo, A.

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D. Shcherbakov, A. Knörzer, S. Espenhahn, R. Hilbig, U. Haas, and M. Blum, “Sensitivity differences in fish offer near-infrared vision as an adaptable evolutionary trait,” PLoS ONE 8, e64429 (2013).
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J. M. Schartau, B. Sjögreen, Y. L. Gagnon, and R. H. H. Kröger, “Optical plasticity in the crystalline lenses of the cichlid fish Aequidens pulcher,” Curr. Biol. 19, 122–126 (2009).
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J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
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B. Karpestam, J. Gustafsson, N. Shashar, G. Katzir, and R. H. H. Kröger, “Multifocal lenses in coral reef fishes,” J. Exp. Biol. 210, 2923–2931 (2007).
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Gustafsson, O. S. E.

O. S. E. Gustafsson, S. P. Collin, and R. H. H. Kröger, “Early evolution of multifocal optics for well-focused colour vision in vertebrates,” J. Exp. Biol. 211, 1559–1564 (2008).
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J. Janssen, N. W. Pankhurst, and G. R. Harbison, “Swimming and body orientation of Notolepis rissoi in relation to lateral line and visual function,” J. Mar. Biol. Assoc. U.K. 72, 877–886 (1992).
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D. Shcherbakov, A. Knörzer, S. Espenhahn, R. Hilbig, U. Haas, and M. Blum, “Sensitivity differences in fish offer near-infrared vision as an adaptable evolutionary trait,” PLoS ONE 8, e64429 (2013).
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K. E. O’Quin, C. M. Hofmann, H. A. Hofmann, and K. L. Carleton, “Parallel evolution of opsin gene expression in African cichlid fishes,” Mol. Biol. Evol. 27, 2839–2854 (2010).
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K. E. O’Quin, C. M. Hofmann, H. A. Hofmann, and K. L. Carleton, “Parallel evolution of opsin gene expression in African cichlid fishes,” Mol. Biol. Evol. 27, 2839–2854 (2010).
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J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
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J. K. Bowmaker and D. M. Hunt, “Evolution of vertebrate visual pigments,” Curr. Biol. 16, R484–R489 (2006).
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J. W. Parry, K. L. Carleton, T. Spady, A. Carboo, D. M. Hunt, and J. K. Bowmaker, “Mix and match color vision: Tuning spectral sensitivity by differential opsin gene expression in Lake Malawi cichlids,” Curr. Biol. 15, 1734–1739 (2005).
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J. Janssen, N. W. Pankhurst, and G. R. Harbison, “Swimming and body orientation of Notolepis rissoi in relation to lateral line and visual function,” J. Mar. Biol. Assoc. U.K. 72, 877–886 (1992).
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J. Bezanson, A. Edelman, S. Karpinski, and V. B. Shah, “Julia: a fresh approach to numerical computing,” arXiv:1411.1607 (2014).

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B. Karpestam, J. Gustafsson, N. Shashar, G. Katzir, and R. H. H. Kröger, “Multifocal lenses in coral reef fishes,” J. Exp. Biol. 210, 2923–2931 (2007).
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D. Shcherbakov, A. Knörzer, S. Espenhahn, R. Hilbig, U. Haas, and M. Blum, “Sensitivity differences in fish offer near-infrared vision as an adaptable evolutionary trait,” PLoS ONE 8, e64429 (2013).
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A. Koskelainen, P. Ala-Laurila, N. Fyhrquist, and K. Donner, “Measurement of thermal contribution to photoreceptor sensitivity,” Nature 403, 220–223 (2000).
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O. S. Gustafsson, P. Ekström, and R. H. Kröger, “A fibrous membrane suspends the multifocal lens in the eyes of lampreys and African lungfishes,” J. Morphol. 271, 980–989 (2010).

R. H. Kröger and R. D. Fernald, “Regulation of eye growth in the African cichlid fish Haplochromis burtoni,” Vis. Res. 34, 1807–1814 (1994).
[Crossref]

Kröger, R. H. H.

Y. L. Gagnon, B. Söderberg, and R. H. H. Kröger, “Optical advantages and function of multifocal spherical fish lenses,” J. Opt. Soc. Am. A 29, 1786–1793 (2012).
[Crossref]

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[Crossref]

J. M. Schartau, R. H. H. Kröger, and B. Sjögreen, “Short-term culturing of teleost crystalline lenses combined with high-resolution optical measurements,” Cytotechnology 62, 167–174 (2010).
[Crossref]

R. H. H. Kröger, K. A. Fritsches, and E. J. Warrant, “Lens optical properties in the eyes of large marine predatory teleosts,” J. Comp. Physiol. A 195, 175–182 (2009).
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[Crossref]

O. S. E. Gustafsson, S. P. Collin, and R. H. H. Kröger, “Early evolution of multifocal optics for well-focused colour vision in vertebrates,” J. Exp. Biol. 211, 1559–1564 (2008).
[Crossref]

O. E. Lind, A. Kelber, and R. H. H. Kröger, “Multifocal optical systems and pupil dynamics in birds,” J. Exp. Biol. 211, 2752–2758 (2008).
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F. D. Hanke, R. H. H. Kröger, U. Siebert, and G. Dehnhardt, “Multifocal lenses in a monochromat: the harbour seal,” J. Exp. Biol. 211, 3315–3322 (2008).
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Y. L. Gagnon, B. Söderberg, and R. H. H. Kröger, “Effects of the peripheral layers on the optical properties of spherical fish lenses,” J. Opt. Soc. Am. A 25, 2468–2475 (2008).
[Crossref]

B. Karpestam, J. Gustafsson, N. Shashar, G. Katzir, and R. H. H. Kröger, “Multifocal lenses in coral reef fishes,” J. Exp. Biol. 210, 2923–2931 (2007).
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T. Malmström and R. H. H. Kröger, “Pupil shapes and lens optics in the eyes of terrestrial vertebrates,” J. Exp. Biol. 209, 18–25 (2006).
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R. H. H. Kröger and A. Gislen, “Compensation for longitudinal chromatic aberration in the eye of the firefly squid, Watasenia scintillans,” Vis. Res. 44, 2129–2134 (2004).
[Crossref]

R. H. H. Kröger, M. C. W. Campbell, R. D. Fernald, and H. J. Wagner, “Multifocal lenses compensate for chromatic defocus in vertebrate eyes,” J. Comp. Physiol. A 184, 361–369 (1999).
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P. E. Malkki, E. Löfblad, and R. H. H. Kröger, “Species specific differences in the optical properties of crystalline lenses of fishes,” in ARVO Annual Meeting Abstract Search and Program Planner (2003), Vol. 2003, p. 3483.

R. H. H. Kröger, “Physiological optics in fishes,” in Encyclopedia of Fish Physiology: From Genome to Environment (Elsevier, 2011), pp. 102–109.

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O. E. Lind, A. Kelber, and R. H. H. Kröger, “Multifocal optical systems and pupil dynamics in birds,” J. Exp. Biol. 211, 2752–2758 (2008).
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E. Denton and N. Locket, “Possible wavelength discrimination by multibank retinae in deep-sea fishes,” J. Mar. Biol. Assoc. U.K. 69, 409–436 (1989).
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E. Loew and V. Govardovskii, “Photoreceptors and visual pigments in the red-eared turtle, Trachemys scripta elegans,” Visual Neurosci. 18, 753–757 (2001).
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B. E. Dalton, E. R. Loew, T. W. Cronin, and K. L. Carleton, “Spectral tuning by opsin coexpression in retinal regions that view different parts of the visual field,” Proc. R. Soc. London B 281, 20141980 (2014).
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P. E. Malkki, E. Löfblad, and R. H. H. Kröger, “Species specific differences in the optical properties of crystalline lenses of fishes,” in ARVO Annual Meeting Abstract Search and Program Planner (2003), Vol. 2003, p. 3483.

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J. N. Lythgoe, W. R. A. Muntz, J. C. Partridge, J. Shand, and D. M. B. Williams, “The ecology of the visual pigments of snappers (Lutjanidae) on the great barrier reef,” J. Comp. Physiol. A 174, 461–467 (1994).
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P. E. Malkki and R. H. H. Kröger, “Visualization of chromatic correction of fish lenses by multiple focal lengths,” J. Opt. A 7, 691–700 (2005).
[Crossref]

P. E. Malkki, E. Löfblad, and R. H. H. Kröger, “Species specific differences in the optical properties of crystalline lenses of fishes,” in ARVO Annual Meeting Abstract Search and Program Planner (2003), Vol. 2003, p. 3483.

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T. Malmström and R. H. H. Kröger, “Pupil shapes and lens optics in the eyes of terrestrial vertebrates,” J. Exp. Biol. 209, 18–25 (2006).
[Crossref]

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F. Busserolles, N. J. Marshall, and S. P. Collin, “The eyes of lanternfishes (myctophidae, teleostei): novel ocular specializations for vision in dim light,” J. Comp. Neurol. 522, 1618–1640 (2014).
[Crossref]

S. E. Temple, N. S. Hart, N. J. Marshall, and S. P. Collin, “A spitting image: specializations in archerfish eyes for vision at the interface between air and water,” Proc. R. Soc. B 277, 2607–2615 (2010).
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Y. Shichida and T. Matsuyama, “Evolution of opsins and phototransduction,” Phil. Trans. R. Soc. B 364, 2881–2895 (2009).
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A. Blest, R. Hardie, P. McIntyre, and D. Williams, “The spectral sensitivities of identified receptors and the function of retinal tiering in the principal eyes of a jumping spider,” J. Comp. Physiol. 145, 227–239 (1981).
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O. Munk and R. D. Frederiksen, “On the function of aphakic apertures in teleosts,” Videnskabelige meddelelser fra Dansk naturhistorisk forening i København 137, 65–94 (1974).

Muntz, W. R. A.

J. N. Lythgoe, W. R. A. Muntz, J. C. Partridge, J. Shand, and D. M. B. Williams, “The ecology of the visual pigments of snappers (Lutjanidae) on the great barrier reef,” J. Comp. Physiol. A 174, 461–467 (1994).
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S. S. Easter and G. N. Nicola, “The development of vision in the zebrafish (Danio rerio),” Develop. Bio. 180, 646–663 (1996).
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M. F. Land and D.-E. Nilsson, Animal Eyes, Animal Biology Series (Oxford, 2002).

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K. E. O’Quin, C. M. Hofmann, H. A. Hofmann, and K. L. Carleton, “Parallel evolution of opsin gene expression in African cichlid fishes,” Mol. Biol. Evol. 27, 2839–2854 (2010).
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D. J. Rennison, G. L. Owens, W. T. Allison, and J. S. Taylor, “Intra-retinal variation of opsin gene expression in the guppy (Poecilia reticulata),” J. Exp. Biol. 214, 3248–3254 (2011).
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J. Janssen, N. W. Pankhurst, and G. R. Harbison, “Swimming and body orientation of Notolepis rissoi in relation to lateral line and visual function,” J. Mar. Biol. Assoc. U.K. 72, 877–886 (1992).
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N. W. Pankhurst, “The relationship of ocular morphology to feeding modes and activity periods in shallow marine teleosts from New Zealand,” Environ. Biol. Fish. 26, 201–211 (1989).
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J. W. Parry, K. L. Carleton, T. Spady, A. Carboo, D. M. Hunt, and J. K. Bowmaker, “Mix and match color vision: Tuning spectral sensitivity by differential opsin gene expression in Lake Malawi cichlids,” Curr. Biol. 15, 1734–1739 (2005).
[Crossref]

Partridge, J. C.

J. N. Lythgoe, W. R. A. Muntz, J. C. Partridge, J. Shand, and D. M. B. Williams, “The ecology of the visual pigments of snappers (Lutjanidae) on the great barrier reef,” J. Comp. Physiol. A 174, 461–467 (1994).
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Pettigrew, J. D.

S. P. Collin and J. D. Pettigrew, “Quantitative comparison of the limits on visual spatial resolution set by the ganglion cell layer in twelve species of reef teleosts,” Brain Behav. Evol. 34, 184–192 (1989).
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D. J. Rennison, G. L. Owens, W. T. Allison, and J. S. Taylor, “Intra-retinal variation of opsin gene expression in the guppy (Poecilia reticulata),” J. Exp. Biol. 214, 3248–3254 (2011).
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Schartau, J. M.

J. M. Schartau, R. H. H. Kröger, and B. Sjögreen, “Short-term culturing of teleost crystalline lenses combined with high-resolution optical measurements,” Cytotechnology 62, 167–174 (2010).
[Crossref]

J. M. Schartau, B. Sjögreen, Y. L. Gagnon, and R. H. H. Kröger, “Optical plasticity in the crystalline lenses of the cichlid fish Aequidens pulcher,” Curr. Biol. 19, 122–126 (2009).
[Crossref]

Shah, V. B.

J. Bezanson, A. Edelman, S. Karpinski, and V. B. Shah, “Julia: a fresh approach to numerical computing,” arXiv:1411.1607 (2014).

Shand, J.

J. N. Lythgoe, W. R. A. Muntz, J. C. Partridge, J. Shand, and D. M. B. Williams, “The ecology of the visual pigments of snappers (Lutjanidae) on the great barrier reef,” J. Comp. Physiol. A 174, 461–467 (1994).
[Crossref]

Shashar, N.

Y. L. Gagnon, N. Shashar, and R. H. H. Kröger, “Adaptation in the optical properties of the crystalline lens in the eyes of the lessepsian migrant Siganus rivulatus,” J. Exp. Biol. 214, 2724–2729 (2011).
[Crossref]

B. Karpestam, J. Gustafsson, N. Shashar, G. Katzir, and R. H. H. Kröger, “Multifocal lenses in coral reef fishes,” J. Exp. Biol. 210, 2923–2931 (2007).
[Crossref]

Shcherbakov, D.

D. Shcherbakov, A. Knörzer, S. Espenhahn, R. Hilbig, U. Haas, and M. Blum, “Sensitivity differences in fish offer near-infrared vision as an adaptable evolutionary trait,” PLoS ONE 8, e64429 (2013).
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Shichida, Y.

Y. Shichida and T. Matsuyama, “Evolution of opsins and phototransduction,” Phil. Trans. R. Soc. B 364, 2881–2895 (2009).
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Shukolyukov, S.

J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
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Sideleva, V.

J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
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Siebert, U.

F. D. Hanke, R. H. H. Kröger, U. Siebert, and G. Dehnhardt, “Multifocal lenses in a monochromat: the harbour seal,” J. Exp. Biol. 211, 3315–3322 (2008).
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J. G. Sivak and W. R. Bobier, “Chromatic aberration of the fish eye and its effect on refractive state,” Vis. Res. 18, 453–455 (1978).
[Crossref]

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[Crossref]

J. G. Sivak, “Accommodative lens movements in fishes: movement along the pupil axis vs movement along the pupil plane,” Vis. Res. 15, 825–828 (1975).
[Crossref]

J. K. Bowmaker, V. Govardovskii, S. Shukolyukov, J. L. Zueva, D. Hunt, V. Sideleva, and O. Smirnova, “Visual pigments and the photic environment: the cottoid fish of Lake Baikal,” Vis. Res. 34, 591–605 (1994).
[Crossref]

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R. D. Fernald and S. E. Wright, “Growth of the visual system in the African cichlid fish, Haplochromis burtoni: accommodation,” Vis. Res. 25, 163–170 (1985).
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W. Charman and J. Tucker, “The optical system of the goldfish eye,” Vis. Res. 13, 1–8 (1973).
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Supplementary Material (4)

NameDescription
» Visualization 1: MP4 (558 KB)      Rotational photography of a Roach head demonstrating the loss of central BEPs at oblique viewing angles in a horizontal rotational plane (i.e., a vertical rotational axis).
» Visualization 2: MP4 (610 KB)      Rotational photography of a Roach head demonstrating the loss of central BEPs at oblique viewing angles in a vertical rotational plane (i.e., a horizontal rotational axis).
» Visualization 3: MP4 (732 KB)      Rotational photography of a Perch head demonstrating the loss of central BEPs at oblique viewing angles in a horizontal rotational plane (i.e. a vertical rotational axis).
» Visualization 4: MP4 (849 KB)      Rotational photography of a Perch head demonstrating the loss of central BEPs at oblique viewing angles in a vertical rotational plane (i.e. a horizontal rotational axis).

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Figures (6)

Fig. 1.
Fig. 1. Graphical simplification of the multifocal principle and how lens occlusion affects the perceived image quality. Target on the left is a fish with five jagged stripes. Each stripe reflects a different wavelength. The light is reflected from the target, gets refracted by the multifocal lens, absorbed by a trichromatic retina, and finally generates an image. The final image on the right is the three retinal channels directly translated to the red, green, and blue channels of an RGB image (approximating what the target would look like to this specific viewer). In the top part of the diagram (a) the viewing angle is perpendicular to the plane of the iris, while in the bottom part (b) the eye is accommodated (the lens is no longer in the center of the eyeball) and rotated differently so that the image falls on a peripheral region of the retina. Notice how only the wavelengths that the lens focuses correctly are sharp (this is a simplification; in nature multifocal lenses are not so discrete) while the other wavelengths are defocused (i.e., 500 and 600 nm). In (a), the retina’s sensitivities are matched to the wavelengths best focused by the lens (notice how the lambda max of the sensitivity curves are aligned with the most focused images); therefore, it is those wavelengths that are most absorbed. Finally, it is the sum of these signals that provide the final image. The defocused wavelengths do not contribute to this image due to the retina’s insensitivity to these wavelengths. Bottom part (b) illustrates how occlusion results in a mismatch between the retina and the lens leading to a defocused image. Here, some of the lens is occluded (e.g., the whole central zone) preventing some wavelengths (e.g., 650 nm) from being focused to the retina’s plane. Because the retina is sensitive to those now defocused wavelengths they still contribute to the final image (notice how the red fish head is now defocused).
Fig. 2.
Fig. 2. Example of three combinations of viewing angles (from top to bottom: 85°, 45°, and 5°) and lens positions (from top to bottom: 0, 0.38, and 0.75 R). Left column, top view, illustrates the incoming light and the position of the lens relative to the iris. Middle column, side view, is the lens as it is viewed from the direction of the incoming light. Blue ellipse is the edge of the iris; green line defines the area through which light can refract through the lens and reach the retina; red/gray concentric circles are the possible BEPs, where the red segments are the ones that contribute to the image and the gray are the ones that do not. Right column, available BEP, availability plots of the BEPs. The x axis is BEP as a proportion of the lens radius (R), while the y axis is BEP availability in percent.
Fig. 3.
Fig. 3. Rotational photography of a fish head demonstrating the loss of central BEPs at oblique viewing angles in a horizontal rotational plane (i.e., a vertical rotational axis). We have arbitrarily overlaid colored circles on the lens to assist with visualizing the change in transmission through various BEPs; however, these are not meant to indicate spectral quality of the light best focused by these regions of the lens. For instance, note how the red central portion of the lens is occluded at angles greater than 70° from the central visual axis (90°) in the roach (Scardinius erythrophthalmus) and how parts of the yellow middle portion of the lens are occluded at more lateral viewing angles (see Visualization 1, Visualization 2)
Fig. 4.
Fig. 4. BEP availability at different viewing angles and lens positions (a)–(e), and their respective image brightness (f). The x axis in the availability plots is BEP as a proportion of the lens radius (R), while the y axis is the availability (in percent) of each BEP. Panes (a) to (e) show the availability for viewing angles 85°, 65°, 45°, 25°, and 5°, respectively. The different lens positions (0, 0.19, 0.38, 0.56, and 0.75 R) are denoted with different colored lines (see legend at the top of the figure). Pane (f) describes image brightness as a function of viewing angle and lens position. The radial axis is brightness (where zero is no brightness at all and one is the maximum brightness possible), and the angular axis is viewing angle (anteroposterior symmetry made the 90°–180° redundant). The positions of the lens are color coded in the same way as in the availability plots.
Fig. 5.
Fig. 5. Rotational photography of a fish head demonstrating the effect an aphakic space might have on lens occlusion. Perch (Perca fluviatilis) shows the advantage of the aphakic space at the front of the eye, which extends the use of the central (red colored) portion of the lens by nearly 30° while exposing more of the middle (yellow colored) portions (see Visualization 3, Visualization 4).
Fig. 6.
Fig. 6. Effects of an aphakic space and a curved iris on the availability of BEPs. (a) Example of an aphakic space in Lingcod (Ophiodon elongatus). (b) Comparison between an eye with (black) and without (gray) an aphakic space. In this case, the BEP availability would increase for light coming from both directions (dark blue and dark red rays). However, stray light (yellow arrow) can now enter the eye and degrade image contrast. (c) Example of a curved iris in archerfish (Toxotes chatareus). (d) Illustration of incoming light rays entering an eye with a planar iris (gray) compared with an eye with a curved iris (black). The curved iris would alter the availability of BEPs by allowing more rays to enter the eye from one viewing angle (from the left; dark blue rays) than a planar iris would (bright blue rays). Rays coming from the other side of the eye (from the right; dark red) and exiting the lens would, however, be blocked by the curved iris (dark red rays). This adaptation is thus beneficial for improving vision in one direction without the costs of light leakage associated with an aphakic space (yellow arrow representing stray light is blocked by the curved iris as well as the planar one). Notice that, while these two adaptations are different, they may occur to some degree in the same species at the same time (e.g., archerfish).

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