Optics and Vision in Invertebrates

Land, M. F.

doi:10.1007/978-3-642-66907-1_4

Cited by 394 publications

(462 citation statements)

References 146 publications

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“…the square of the inverse f-number commonly used in optics (Land, 1981;Martin, 1982Martin, , 1983. Given everything else remains constant, the eye with a lower f-number is expected to have better light sensitivity, and this is relatively well supported by behavioral measurements of the absolute visual threshold (Martin, 1982).…”

Section: Introductionmentioning

confidence: 98%

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Quantitative estimates of visual performance features in fossil birds

Schmitz¹

2009

Journal of Morphology

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Eyeball structures such as the lens diameter (LD) and axial length are generally assumed to be highly correlated with optically meaningful parameters. However, these optical constraints on eyeball macroanatomy have never been tested explicitly. Tradeoffs between benefits of improved visual performance and cost of adaptation from an increase of tissue production predict that when eyeball size increases, optical parameters such as posterior nodal distance and maximum entrance pupil diameter should increase isometrically with eyeball axial length and LD, respectively. Here I show quantitatively that the interspecific allometry of the avian eye largely follows this predicted isometry. Additionally, I elaborate a method to estimate optically significant eyeball soft-tissue dimensions from scleral ring and orbit morphology based on analyses of interspecific allometry in Aves. The stringent correlations between avian eyeball morphology and optical function render this system ideal for the analysis of form-function relationships and allow for an accurate estimate of optically significant eyeball soft-tissue dimensions such as diameter, axial length, and LD in fossil species.

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Section: Introductionmentioning

confidence: 98%

“…Visual performance is characterized by two main qualities: acuity and light sensitivity. Acuity, usually given as spatial sampling frequency, expresses the fineness of detail that can be discriminated (Land, 1981). Spatial sampling frequency depends on two variables.…”

Section: Introductionmentioning

confidence: 99%

Quantitative estimates of visual performance features in fossil birds

Schmitz¹

2009

Journal of Morphology

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“…The optical sensitivity was calculated using Land's equation (for the absorption of light at the absorbance peak wavelength, Land, 1981) and a modification of Land's equation derived by Warrant and Nilsson (1998) for the absorption of white light. Optical sensitivity~S!…”

Section: Estimation Of Optical Sensitivitymentioning

confidence: 99%

“…For monochromatic light at the preferred wavelength of the photoreceptor, F l max ϭ 1 Ϫ e Ϫkl (Land, 1981;Warrant & McIntyre, 1990). All calculations assume that the photoreceptors capture photons from an extended light source (Land, 1981;Warrant & Nilsson, 1998).…”

Section: S P Collin Et Almentioning

confidence: 99%

Vision in the southern hemisphere lampreyMordacia mordax: Spatial distribution, spectral absorption characteristics, and optical sensitivity of a single class of retinal photoreceptor

et al. 2004

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The dorso-laterally located eyes of the southern hemisphere lamprey Mordacia mordax (Agnatha) contain a single morphological type of retinal photoreceptor, which possesses ultrastructural characteristics of both rods and cones. This photoreceptor has a large refractile ellipsosome in the inner segment and a long cylindrical outer segment surrounded by a retinal pigment epithelium that contains two types of tapetal reflectors. The photoreceptors form a hexagonal array and attain their peak density (33,200 receptors0mm 2 ) in the ventro-temporal retina. Using the size and spacing of the photoreceptors and direct measures of aperture size and eye dimensions, the peak spatial resolving power and optical sensitivity are estimated to be 1.7 cycles deg Ϫ1 (minimum separable angle of 34 ' 7 '' ) and 0.64 mm 2 steradian (white light) and 1.38 mm 2 steradian (preferred wavelength or l max ), respectively. Microspectrophotometry reveals that the visual pigment located within the outer segment is a rhodopsin with a wavelength of maximum absorbance (l max ) at 514 nm. The ellipsosome has very low absorptance (Ͻ0.05) across the measured spectrum (350-750 nm) and probably does not act as a spectral filter. In contrast to all other lampreys studied, the optimized receptor packing, the large width of the ellipsosome-bearing inner segment, together with the presence of a retinal tapetum in the photophobic Mordacia, all represent adaptations for low light vision and optimizing photon capture.

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“…During a yaw body saccade the head turns at a higher angular speed than the body, thus further minimizing the time over which prominent rotational optic flow is generated (Schilstra and van Hateren 1998). The saccadic viewing strategy largely segregates image flow resulting from rotational movements from image flow resulting from translational movements of the animal helping to detect disturbances to its intended flight path (Collett 1980), and the relative distance of objects, which create discontinuities in the translational optic flow field (Blaj and van Hateren 2004;Eckert and Zeil 2001;Land and Collett 1997;Schilstra et al 1998;Srinivasan 1993;van Hateren et al 1999). During translation a nearby object appears to move faster than its background thereby generating visual motion parallax cues that can provide the perceived world with a third dimension (blowflies: Kimmerle et al 1996; bees: Lehrer et al 1988;Srinivasan et al 1989).…”

Section: Introductionmentioning

confidence: 99%

Responses of blowfly motion-sensitive neurons to reconstructed optic flow along outdoor flight paths

et al. 2005

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The retinal image flow a blowfly experiences in its daily life on the wing is determined by both the structure of the environment and the animal's own movements. To understand the design of visual processing mechanisms, there is thus a need to analyse the performance of neurons under natural operating conditions. To this end, we recorded flight paths of flies outdoors and reconstructed what they had seen, by moving a panoramic camera along exactly the same paths. The reconstructed image sequences were later replayed on a fast, panoramic flight simulator to identified, motion sensitive neurons of the so-called horizontal system (HS) in the lobula plate of the blowfly, which are assumed to extract self-motion parameters from optic flow. We show that under real life conditions HS-cells not only encode information about self-rotation, but are also sensitive to translational optic flow and, thus, indirectly signal information about the depth structure of the environment. These properties do not require an elaboration of the known model of these neurons, because the natural optic flow sequences generate-at least qualitatively-the same depth-related response properties when used as input to a computational HS-cell model and to real neurons.

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Optics and Vision in Invertebrates

Cited by 394 publications

References 146 publications

Quantitative estimates of visual performance features in fossil birds

Quantitative estimates of visual performance features in fossil birds

Vision in the southern hemisphere lampreyMordacia mordax: Spatial distribution, spectral absorption characteristics, and optical sensitivity of a single class of retinal photoreceptor

Responses of blowfly motion-sensitive neurons to reconstructed optic flow along outdoor flight paths

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