The spectral transmission of ocular media suggests ultraviolet sensitivity is widespread among mammals

Although ultraviolet (UV) sensitivity is widespread among animals it is considered rare in mammals, being restricted to the few species that have a visual pigment maximally sensitive (λmax) below 400 nm. However, even animals without such a pigment will be UV-sensitive if they have ocular media that transmit these wavelengths, as all visual pigments absorb significant amounts of UV if the energy level is sufficient. Although it is known that lenses of diurnal sciurid rodents, tree shrews and primates prevent UV from reaching the retina, the degree of UV transmission by ocular media of most other mammals without a visual pigment with λmax in the UV is unknown. We examined lenses of 38 mammalian species from 25 families in nine orders and observed large diversity in the degree of short-wavelength transmission. All species whose lenses removed short wavelengths had retinae specialized for high spatial resolution and relatively high cone numbers, suggesting that UV removal is primarily linked to increased acuity. Other mammals, however, such as hedgehogs, dogs, cats, ferrets and okapis had lenses transmitting significant amounts of UVA (315–400 nm), suggesting that they will be UV-sensitive even without a specific UV visual pigment

Evolution of the eyes of vipers with and without infrared-sensing pit organs

We examined lens and brille transmittance, photoreceptors, visual pigments, and visual opsin gene sequences of viperid snakes with and without infrared-sensing pit organs. Ocular media transmittance is high in both groups. Contrary to previous reports, small as well as large single cones occur in pit vipers. Non-pit vipers differ from pit vipers in having a twotiered retina, but few taxa have been examined for this poorly understood feature. All vipers sampled express rh1, sws1 and lws visual opsin genes. Opsin spectral tuning varies but not in accordance with the presence/absence of pit organs, and not always as predicted from gene sequences. The visual opsin genes were generally under purifying selection, with positive selection at spectral tuning amino acids in RH1 and SWS1 opsins, and at retinal pocket stabilization sites in RH1 or LWS (and without substantial differences between pit and nonpit vipers). Lack of evidence for sensory trade-off between viperid eyes (in the aspects examined) and pit organs might be explained by the high degree of neural integration of vision and infrared detection; the latter representing an elaboration of an existing sense with addition of a novel sense organ, rather than involving the evolution of a wholly novel sensory system

Arctic reindeer extend their visual range into the ultraviolet

The Arctic has extreme seasonal changes in light levels and is proportionally UV-rich because of scattering of the shorter wavelengths and their reflection from snow and ice. Here we show that the cornea and lens in Arctic reindeer do not block all UV and that the retina responds electrophysiologically to these wavelengths. Both rod and cone photoreceptors respond to UV at low-intensity stimulation. Retinal RNA extraction and in vitro opsin expression show that the response to UV is not mediated by a specific UV photoreceptor mechanism. Reindeer thus extend their visual range into the short wavelengths characteristic of the winter environment and periods of extended twilight present in spring and autumn. A specific advantage of this short-wavelength vision is the use of potential information caused by differential UV reflections known to occur in both Arctic vegetation and different types of snow. UV is normally highly damaging to the retina, resulting in photoreceptor degeneration. Because such damage appears not to occur in these animals, they may have evolved retinal mechanisms protecting against extreme UV exposure present in the daylight found in the snow-covered late winter environment

Aerospace Medicine and Biology. A continuing bibliography with indexes

This bibliography lists 244 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1981. Aerospace medicine and aerobiology topics are included. Listings for physiological factors, astronaut performance, control theory, artificial intelligence, and cybernetics are included

Photoreceptor System for Melatonin Regulation and Phototherapy

The present invention involves a light system for stimulating or regulating neuroendocrine, circadian, and photoneural systems in mammals based upon the discovery of peak sensitivity ranging from 425-505 nm; a light meter system for quantifying light which stimulates or regulates mammalian circadian, photoneural, and neuroendocrine systems. The present invention also relates to translucent and transparent materials, and lamps or other light sources with or without filters capable of stimulating or regulating neuroendocrine, circadian, and photoneural systems in mammals. Additionally, the present invention involves treatment of mammals with a wide variety of disorders or deficits, including light responsive disorders, eating disorders, menstrual cycle disorders, non-specific alerting and performance deficits, hormone-sensitive cancers, and cardiovascular disorders

Visual pigments, ocular filters and the evolution of snake vision

Much of what is known about the molecular evolution of vertebrate vision comes from studies of mammals, birds and fish. Reptiles (especially snakes) have barely been sampled in previous studies despite their exceptional diversity of retinal photoreceptor complements. Here we analyse opsin gene sequences and ocular media transmission for up to 69 species to investigate snake visual evolution. Most snakes express three visual opsin genes (rh1, sws1, lws). These opsin genes (especially rh1 and sws1) have undergone much evolutionary change, including modifications of amino acid residues at sites of known importance for spectral tuning, with several tuning site combinations unknown elsewhere among vertebrates. These changes are particularly common among dipsadine and colubrine ‘higher’ snakes. All three opsin genes are inferred to be under purifying selection, though dN/dS varies with respect to some lineages, ecologies, and retinal anatomy. Positive selection was inferred at multiple sites in all three opsins, these being concentrated in transmembrane domains and thus likely to have a substantial effect on spectral tuning and other aspects of opsin function. Snake lenses vary substantially in their spectral transmission. Snakes active at night and some of those active by day have very transmissive lenses, while some primarily diurnal species cut out shorter wavelengths (including UVA). In terms of retinal anatomy, lens transmission, visual pigment spectral tuning and opsin gene evolution the visual system of snakes is exceptionally diverse compared to all other extant tetrapod orders

Aerospace medicine and biology. A continuing bibliography with indexes, supplement 206, May 1980

This bibliography lists 169 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1980

Metabolic effects of ultraviolet radiation on the anterior part of the eye

Ultraviolet radiation (UV-R) is an environmental factor known to increase the risk of developing an irreversible opacification of the lens (cataract). Increased irradiance of UV-R to the earth because of depletion of stratospheric ozone is of current concern considering cataract formation. Detailed metabolic information from the cornea, lens and aqueous humour might give valuable knowledge on the biochcemical processes occurring in the eye after exposure to UV-R, and thereby a better understanding of the mechanisms by which UV-R induces cataractogenesis. The purpose of this thesis was to study metabolic effects of exposure to UV-R on the anterior part of the eye. Effects of UV-B (280-315 nm) and UV-A (315-400 nm) on the aqueous humour, cornea and the lens from animal models were investigated by 1H nuclear magnetic resonance (NMR) spectroscopy. Since the lens is composed of functionally distinct anatomical compartments, with different metabolic activity, biochemical changes in various compartments of the lens were analyzed. Application of NMR-based metabonomics was effective to analyze metabolic changes in the anterior part of the eye after exposure to UV-R. High-resolution (HR) magic angle spinning (MAS) 1H NMR spectroscopy provided high quality spectra from intact tissue of cornea and lens, and provided important information about metabolic alteration occurring in these tissues after exposure to UV-R. The results from this thesis show that in vivo UV-B radiation affects metabolism of the anterior compartments of the eye. Metabolic changes were observed in aqueous humour, cornea, lens and in the different compartments of the lens. The antioxidants, glutathione and ascorbate, several amino acids, high energetic phosphates, and compounds important for membrane building and osmoregulation were substantially altered after exposure to UV-B radiation. Several biochemical effects such as oxidation, membrane disruption, osmoregulatory problems, lipid peroxidation, problems with cellular signalling and impairment of growth and protein synthesis were suggested. After UV-A exposure, no observable metabolic alterations were found in the anterior part of the eye in the present animal models.PhD i nevrovitenskapPhD in Neuroscienc

Light manipulation principles in biological photonic systems

© 2013 Science Wise Publishing and DE GRUYTER.The science of light and colour manipulation continues to generate interest across a range of disciplines, from mainstream biology, across multiple physicsbased fields, to optical engineering. Furthermore, the study of light production and manipulation is of significant value to a variety of industrial processes and commercial products. Among the several key methods by which colour is produced in the biological world, this review sets out to describe, in some detail, the specifics of the method involving photonics in animal and plant systems; namely, the mechanism commonly referred to as structural colour generation. Not only has this theme been a very rapidly growing area of physics-based interest, but also it is increasingly clear that the biological world is filled with highly evolved structural designs by which light and colour strongly influence behaviours and ecological functions.We acknowledge the financial support of DARPA contract W911NF-10-C-0069 and of AFOSR grant FA9550-10-1-0020. We also wish to thank Caroline Pouya, Helen Ghiradella, Radislav Potyrailo, Roy Sambles, Shuichi Kinoshita and Doekele Stavenga for helpful discussions

Lens autofluorescence : In aging and cataractous human lenses. Clinical applicability

AbstractThis study was carried out to investigate in vivo the changes of the human lens autofluorescence (AF) with aging and cataractogenesis. Measurements were performed in the blue-green AF range (495 nm/520 nm) using a fluorometer designed, built and now clinically tested in our department.43 random eyes of 43 healthy volunteers aged 6–86 years, five of each decade, were studied for effects of aging and 84 eyes of 84 patients with cortical, nuclear, posterior subcapsular or mixed lens opacities were studied for differences of various cataract types. The results were compared with the back light scatter values obtained by the commercially available Interzeag Lens Opacity Meter 701. Also AF and back light scatter of the lens were measured from 122 smoking males aged 57 to 76 years who participated in a cancer prevention study. The results were compared with the widely used subjective lens opacities classification system, LOCS III. In addition data was collected from 30 randomly chosen eyes of as many subjects with varying degrees of yellow-brown lens coloration in an otherwise healthy eye. We studied the influence of lens yellowing expressed by means of lens AF on visibility of retinal nerve fiber layer in black-and-white images.Lens AF profile consists of anterior and posterior peaks and a central plateau. The height of the anterior peak was used as a measure of the maximum AF value. The square root of the ratio between the posterior and the anterior AF peaks was used for estimating the lens transmission. Our technique was highly reproducible. The coefficient of variation was 3.9% for maximum AF and 2.9% for the lens transmission index.Both the maximum AF and light scatter were exponentially increased with age (r = 0.95 and 0.94, respectively; p In cortical cataracts the AF curve was low and flattened and the maximum AF value was significantly lower than in the age matched control eyes. The highest light scatter values were measured from cortical cataracts, but the correlation between LOCS III cortical grades and light scatter values was rather weak.Posterior subcapsular cataracts cannot be quantified either with AF or with light scatter measurements. Lens yellowing, expressed as lens AF, had an actual effect on retinal nerve fiber layer visibility. AF measurements provided a better prediction about the visibility score than age or visual acuity did.The results of the present study indicate that the lens autofluorescence measurement may be a useful additional tool together with a subjective grading system in the follow-up of optical changes occurring in the nuclear region of the lens.Academic dissertation to be presented with the assent of the Faculty of Medicine, University of Oulu, for public discussion in Autorium 5 of the University Hospital of Oulu, on June 11th, 1999, at 12 noon.Abstract This study was carried out to investigate in vivo the changes of the human lens autofluorescence (AF) with aging and cataractogenesis. Measurements were performed in the blue-green AF range (495 nm/520 nm) using a fluorometer designed, built and now clinically tested in our department. 43 random eyes of 43 healthy volunteers aged 6–86 years, five of each decade, were studied for effects of aging and 84 eyes of 84 patients with cortical, nuclear, posterior subcapsular or mixed lens opacities were studied for differences of various cataract types. The results were compared with the back light scatter values obtained by the commercially available Interzeag Lens Opacity Meter 701. Also AF and back light scatter of the lens were measured from 122 smoking males aged 57 to 76 years who participated in a cancer prevention study. The results were compared with the widely used subjective lens opacities classification system, LOCS III. In addition data was collected from 30 randomly chosen eyes of as many subjects with varying degrees of yellow-brown lens coloration in an otherwise healthy eye. We studied the influence of lens yellowing expressed by means of lens AF on visibility of retinal nerve fiber layer in black-and-white images. Lens AF profile consists of anterior and posterior peaks and a central plateau. The height of the anterior peak was used as a measure of the maximum AF value. The square root of the ratio between the posterior and the anterior AF peaks was used for estimating the lens transmission. Our technique was highly reproducible. The coefficient of variation was 3.9% for maximum AF and 2.9% for the lens transmission index. Both the maximum AF and light scatter were exponentially increased with age (r = 0.95 and 0.94, respectively; p < 0.0001). According to the regression line of AF begins to increase in early childhood. It appears by extrapolation to be absent at birth. In contrast light scatter in the lens was present even in young children. The lens transmission for blue-green light, determined from the lens AF curve, was almost unchanging with age up to 60 years. Thereafter it decreased rapidly and the interindividual variation increased. In cataractous lenses the mean AF and scatter values differed statistically significantly from those of age matched healthy controls. The highest AF values were measured in nuclear cataracts where AF was also related to visual acuity and an increasing yellow-brown colour of the nucleus. About half of the total variation of the transmission index values could be accounted for by changes in nuclear colour as assessed by the LOCS III grading system. The transmission index provided a more precise prediction about nuclear colour and opalescence than age or light scatter did. In cortical cataracts the AF curve was low and flattened and the maximum AF value was significantly lower than in the age matched control eyes. The highest light scatter values were measured from cortical cataracts, but the correlation between LOCS III cortical grades and light scatter values was rather weak. Posterior subcapsular cataracts cannot be quantified either with AF or with light scatter measurements. Lens yellowing, expressed as lens AF, had an actual effect on retinal nerve fiber layer visibility. AF measurements provided a better prediction about the visibility score than age or visual acuity did. The results of the present study indicate that the lens autofluorescence measurement may be a useful additional tool together with a subjective grading system in the follow-up of optical changes occurring in the nuclear region of the lens