Eye lesions in domestic fowl reared under continuous light

Lauber, Jean K.; McGinnis, James

doi:10.1016/0042-6989(66)90073-3

Cited by 60 publications

(33 citation statements)

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“…These include light-induced retinopathy (Lauber and McGinnis, 1966), toxic retinopathy (Matsubara and Kuba, 1970) and several inherited retinal disorders of which four have been studied in detail. Randall et al (1983) described a sex-linked mutant (rdd) characterised by partial retinal dysplasia and subsequent degeneration in which vision is reduced at hatching and progresses to blindness by sexual maturity.…”

Section: Introductionmentioning

confidence: 99%

An inherited retinopathy in commercial breeding chickens

et al. 1988

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SUMMARYImpaired vision was observed in individual birds from several related flocks of layer breeding chickens. The condition was usually apparent by eight weeks of age. Affected birds were unable to perceive food particles on a flat surface or to negotiate a 50 mm bridge, although apparently able to discern large objects and to respond to bright light. On ophthalmoscopic examination of the fundus the choroidal vasculature was usually more readily visualised than in normal chickens and in addition discrete white streaks were often seen to extend peripherally from the base of the pecten. Cataract formation was frequently present by several months of age. The electroretinograms of two affected birds were of abnormally low amplitude. Light microscopy of the retinas of most birds exhibiting blindness showed a generalised reduction in the number of photoreceptors and in the thickness of the outer nuclear layer, although in others there were no obvious abnormalities. The linear fundus lesions represented abrupt thinnings of the retina in which, to a varying degree, the retinal pigment epithelium and photoreceptor inner and outer segment, outer nuclear and outer plexiform layers were disorganised or absent. A mating of affected individuals produced progeny of which 13/14 were obviously ' blind, indicating an hereditary basis for the condition.

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Section: Introductionmentioning

confidence: 99%

An inherited retinopathy in commercial breeding chickens

et al. 1988

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“…The three primary alterations that have been investigated include variations in the diurnal light-dark cycle and the intensity and spectral composition of ambient lighting. These studies have shown that disturbances in the circadian rhythms of ocular mechanisms can interfere with refractive development, [10][11][12] and that both luminance [13][14][15] and chromatic mechanisms 16,17 are involved in the visual regulation of ocular growth. In addition, it has been shown that in comparison with ordinary indoor lighting levels, elevated lighting promotes low degrees of hyperopia, whereas dim lighting levels that are sufficient to maintain normal circadian rhythms promote ocular enlargement and myopia.…”

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confidence: 99%

Visual regulation of refractive development: insights from animal studies

Smith

Hung

Arumugam

2013

Eye

107

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Investigations employing animal models have demonstrated that ocular growth and refractive development are regulated by visual feedback. In particular, lens compensation experiments in which treatment lenses are used to manipulate the eye's effective refractive state have shown that emmetropization is actively regulated by signals produced by optical defocus. These observations in animals are significant because they indicate that it should be possible to use optical treatment strategies to influence refractive development in children, specifically to slow the rate of myopia progression. This review highlights some of the optical performance properties of the vision-dependent mechanisms that regulate refractive error development, especially those that are likely to influence the efficacy of optical treatment strategies for myopia. In this respect, the results from animal studies have been very consistent across species; however, to facilitate extrapolation to clinical settings, results are presented primarily for nonhuman primates. In agreement with preliminary clinical trials, the experimental data show that imposed myopic defocus can slow ocular growth and that treatment strategies that influence visual signals over a large area of the retina are likely to be most effective. Eye (2014) 28, 180-188; doi:10.1038/eye.2013.277; published online 13 December 2013Keywords: myopia; hyperopia; defocus; emmetropization Curtin 1 credits Kepler with being one of the first vision scientists to recognize the association between near work and myopia and for hypothesizing that myopia was an adaptation to near work. Although these seminal observations (circa 1610) have been replicated numerous times and much has been learnt about potential risk factors for the development of common forms of myopia, centuries of research on myopia in humans have failed to provide a clear indication of what it is about near work that promotes the development of myopia or to identify the physiological mechanisms that promote myopia in children as a result of chronic near work. However, beginning in the 1960s, research employing animal models was greatly expanded and began to provide new insights into the effects of visual experience on ocular growth and refractive development.The nature of the visual manipulations that have been employed to characterize refractive development in animals fall into three broad categories. The first category involved either natural or imposed restrictions in viewing distance and was largely motivated by the near work hypothesis. For example, comparisons of refractive errors between feral and domesticated or laboratory-reared animals supported the idea that environments that restrict viewing distance are myopiagenic. 2,3 However, these studies suffered from many of the same confounding issues associated with human studies. 4 A more controlled line of research was begun by Levinsohn 5 and continued most notably by Young, 6-9 who demonstrated that monkeys reared in environments with a maximum viewing distance o...

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“…The rge (retinopathy globe enlarged) chicken develops posterior polar sub capsular cataracts [15]. Toxic cataract genesis has been recorded in birds after nitrophenol administration [16] and birds raised in continuous light suffer from lens opacification in addition to retinal degeneration and globe enlargement [17]. Severe blinding cataracts occurred in ducks suffering from salt toxicosis [18] and cataracts have also been recorded in birds infected with avian encephalomyelitis virus [19] although there was also a genetic component to susceptibility to this agent [20].…”

Section: Introductionmentioning

confidence: 99%

Cataracts in corvids: health and welfare implications of lens opacification in a colony of Western scrub-jays (Aphelocoma californica)

Williams¹,

Salter²

2017

IJAWB

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The development of cataracts in a colony of 55 Western scrub jays ((Aphelocoma californica) kept in a colony is reported, etiopathology discussed and welfare implications debated. Birds were examined with direct and indirect ophthalmoscopy and slit lamp biomicroscopy. Intraocular pressures were measured with a rebound tonometer. Thirty eight birds were diagnosed with some lens opacification, ranging from linear arrangements of small vacuoles to mature cataract. In some birds this lens pathology was seen concurrent with adnexal post-traumatic pathology or with substantial uveitic changes. Behaviour changes were only noted in birds with mature or near-mature cataracts. The lack of significant ultraviolet light and the provision of a suitable avian diet suggest that neither excess light nor inadequate nutrition could be factors in cataractogenesis. While a genetic cause is difficult to exclude, the fact that these were wild caught birds from an outbred population without observed lens pathology in the wild renders this unlikely. We suggest that a post-traumatic aetiology is the likely causative factor in the genesis of lens opacities in these birds. The changes in behaviour and the impact on the welfare of birds with these ocular changes is discussed. IntroductionThe cognitive capacity of avian species has long been underrated; the very phrase 'bird-brained' suggests a pretty minimal executive function in these animals. Yet studies from a small number of investigators -one might particularly highlight Pepperberg's work with African grey parrots [1] or Clayton's studies with scrub-jays [2] -suggest that at least in psittaciformes and corvidae we see species with considerable cognitive abilities. Indeed Emery, working with Clayton, has termed her birds 'feathered apes' because of their superlative decision-making abilities [3]. Such suggestions may have significant implications for keeping these birds in an experimental setting. Here we report the development of cataracts in a majority of scrub jays kept in an experimental colony and discuss the possible etiologies for lens opacification in these birds.Professor Clayton first noted interesting behavioral characteristics of the Western scrub jay (Aphelocoma californica) while undertaking her doctoral studies in the University of California, Davis two decades ago. These birds hide or 'cache' food items for retrieval later but other scrub jays often steal the items after viewing the caching behaviour of one of their compatriots. Clayton recognized that some birds, noting a second bird observing them while caching, then re-hid the food item when the observing bird was no longer present. She realized that such behaviour suggests a 'theory of mind' in the caching bird which can in some way comprehend what the observing bird is thinking and planning to do. Research on a colony of Western scrub-jays brought back to the UK to evaluate their cognitive function has resulted in a large number of scientific research publications, of which a few recent ones are [4][5][6]. ...

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Eye lesions in domestic fowl reared under continuous light

Cited by 60 publications

References 1 publication

An inherited retinopathy in commercial breeding chickens

An inherited retinopathy in commercial breeding chickens

Visual regulation of refractive development: insights from animal studies

Cataracts in corvids: health and welfare implications of lens opacification in a colony of Western scrub-jays (Aphelocoma californica)

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