Retinoscopy of aquatic eyes

Hueter, Robert E.; Gruber, Samuel H.

doi:10.1016/0042-6989(80)90102-9

Cited by 20 publications

(14 citation statements)

References 18 publications

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“…11,17,38,42 By comparison, primates (monkeys) only recover to a limited extent from diffuser-induced myopia. 27,31 Though recovery varies with species, it still may be part of visually guided regulation of eye growth. The choroid of the fish eye may also play a role in this process, as found in other higher vertebrates.…”

Section: Discussionmentioning

confidence: 99%

“…True refractive error is obtained by dividing by 1.33, and all values reported here were corrected in this manner. 31 Retinoscopic values were estimated to be accurate to within Ϯ0.50 D. Means and standard deviations of the results are given to one decimal. Retinoscopic measurements were made along the direction perpendicular to the plane of the pupil, and the results are expressed as the difference between the refractive state, in diopters, of the treated and untreated eyes.…”

Section: Ocular Measurements Refractive States Were Measured Withmentioning

confidence: 99%

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Eyes of a Lower Vertebrate Are Susceptible to the Visual Environment

Shen

Sivak

2007

Invest. Ophthalmol. Vis. Sci.

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Section: Discussionmentioning

confidence: 99%

Section: Ocular Measurements Refractive States Were Measured Withmentioning

confidence: 99%

Eyes of a Lower Vertebrate Are Susceptible to the Visual Environment

Shen

Sivak

2007

Invest. Ophthalmol. Vis. Sci.

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“…Moreover, because the measurements are made underwater, the vergence of the retinoscopic reflection must be corrected for in the air-water interface, or the degree of ametropia in either myopic or hyperopic eyes will be overestimated (Hueter and Gruber 1980). Perhaps the most difficult issue is in regard to the source of the reflection in the eye.…”

Section: The State Of Focusmentioning

confidence: 99%

Aquatic Adaptations in Fish Eyes

Fernald

1988

Sensory Biology of Aquatic Animals

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To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts oflight, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.(Charles Darwin, The Origin of Species, 1859, p. 168) Of all the sense organs, eyes have probably attracted the most attention because of both their central importance and intricate construction. Darwin knew that such "organs of extreme perfection and complication" posed a crucial test of his theory because they seemed too good to have been shaped by natural selection (Darwin [1859(Darwin [ ] 1958. Since eyes must obey the optical laws of physics, fundamental physical constraints on their structure provide an important analytical basis for understanding adaptive ocular specializations. In light of these physical constraints, inferences about the selective forces that have shaped eye design can be made with some confidence, particularly in the study of aquatic eyes.Fish eyes offer an unusually interesting and accessible opportunity to ask general questions about visual evolution, development, and function (Fernald 1984). Although a great deal of work has been done on the domestic goldfish, this narrow experimental focus obscures the fact that bony fish form the largest class of vertebrates, comprising over 25,000 species. Evidence of their success can be found in the adaptive radiation of forms occupying an extraordinary range of habitats. Fish eyes and brains variously reflect success in mastering different life history strategies with the unsurprising general rule that the favored sensory modality occupies disproportionately more brain volume (see Geiger 1956).There are several summaries of information about the fish eye available, so here I will present primarily recent findings. Since fish eyes have a relatively standard construction, with some deviations resulting from adaptations to specialized situations, I will first discuss underlying physical constraints that apply generally to the evolution of eyes. Then I will analyze various structures that have evolved to meet these constraints in teleost fish and, finally, present some new evidence about novel solutions to problems posed by regulation of fish eye growth.

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“…A decreasing focal ratio with eye growth is noted in two other elasmobranch species (Sivak and Luer, 1991;Harahush, 2009) and a few teleost fishes (Shand et al, 1999;Kröger et al, 2001;McPherson, 2004). Interestingly, the range in focal ratio observed between elasmobranch species (2.3-3.3) (Sivak, 1978a;Hueter, 1980;Hueter and Gruber, 1980;Lisney, 2004;Lisney and Collin, 2004) covers a similar range to that shown between the ontogenetic size ranges investigated in C. plumbeus (2.7-3.3) and S. mitsukurii (2.5-2.9). While species differences in focal ratio may exist, these results caution that some differences in focal ratio, as previously shown between elasmobranch species, may be an artefact of indiscriminate sampling of different sized animals.…”

Section: Focal Properties Of the Eyementioning

confidence: 57%

Visual optics and ecomorphology of the growing shark eye: a comparison between deep and shallow water species

Litherland

Collin

Fritsches

2009

Journal of Experimental Biology

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SUMMARYElasmobranch fishes utilise their vision as an important source of sensory information, and a range of visual adaptations have been shown to reflect the ecological diversity of this vertebrate group. This study investigates the hypotheses that visual optics can predict differences in habitat and behaviour and that visual optics change with ontogenetic growth of the eye to maintain optical performance. The study examines eye structure, pupillary movement, transmission properties of the ocular media, focal properties of the lens, tapetum structure and variations in optical performance with ontogenetic growth in two elasmobranch species: the carcharhinid sandbar shark, Carcharhinus plumbeus, inhabiting nearshore coastal waters, and the squalid shortspine spurdog, Squalus mitsukurii, inhabiting deeper waters of the continental shelf and slope. The optical properties appear to be well tuned for the visual needs of each species. Eyes continue to grow throughout life, resulting in an ontogenetic shift in the focal ratio of the eye. The eyes of C. plumbeus are optimised for vision under variable light conditions, which change during development as the animal probes new light environments in its search for food and mates. By contrast, the eyes of S. mitsukurii are specifically adapted to enhance retinal illumination within a dim light environment, and the detection of bioluminescent prey may be optimised with the use of lenticular short-wavelength-absorbing filters. Our findings suggest that the light environment strongly influences optical features in this class of vertebrates and that optical properties of the eye may be useful predictors of habitat and behaviour for lesser-known species of this vertebrate group.Key words: shark, eye growth, ocular media, focal ratio, tapetum, visual ecology. THE JOURNAL OF EXPERIMENTAL BIOLOGY 3584ocular parameters adapt to different light environments and influence the optical image reaching the retina. We reveal that the visual system of C. plumbeus has adapted to facilitate vision in the fluctuating light environment of coastal neritic waters, while S. mitsukurii has adapted to maximise light capture in the dim, semiextended light environment of the mesopelagic zone. MATERIALS AND METHODS Source and maintenance of animalsA population of S. mitsukurii was sampled (N26) from the insular shelf of the Hawaiian Island chain in the Central Pacific. Three populations of C. plumbeus were sampled to represent the extremes in visual environment encountered by this species; a tropical population inhabiting the insular shelf of the Hawaiian Island chain (C. plumbeus H1 ; transparent oceanic waters, depth >70m, N88, , a temperate population inhabiting the continental shelf in the north-western Atlantic Ocean (C. plumbeus H2 ; turbid estuarine waters, depth <10m, N40, TL55-110cm) and a subtropical population inhabiting the continental shelf of eastern Australia in the Western Pacific (C. plumbeus H3 ; green coastal waters, depth >50m, N57, TL50-187cm) (Table1). Tissue samples ...

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Retinoscopy of aquatic eyes

Cited by 20 publications

References 18 publications

Eyes of a Lower Vertebrate Are Susceptible to the Visual Environment

Eyes of a Lower Vertebrate Are Susceptible to the Visual Environment

Aquatic Adaptations in Fish Eyes

Visual optics and ecomorphology of the growing shark eye: a comparison between deep and shallow water species

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