Age-related adaptive responses of mitochondria of the retinal pigment epithelium to the everyday blue LED lighting.

The effect of everyday blue light (λ = 440-460 nm) on mitochondria of the retinal pigment epithelium of different age groups of Japanese quail was studied using electron microscopy, morphometric methods, and biochemical analysis. We have found a significant increase in the number of mitochondria, including those modified, mainly in young birds. In addition, cell metabolic activity increased in response to blue lighting. These changes are assumed to reflect an adaptive response of mitochondria aimed at neutralizing the phototoxic effect of blue light caused by accumulation of lipofuscin granules.

Photoinduced changes in subcellular structures of the retinal pigment epithelium from the Japanese quail Coturnix japonica.

Fifteen-week-old sexually mature female Japanese quails (Coturnix japonica) grown under various lighting conditions were used in the study. It was found that the number of mitochondria and phagosomes was increased by 1.5-fold in the retinal pigment epithelium from birds reared for 95 days under blue light (440-470 nm) vs. reduced blue light component conditions. Also, it was found that egg production was increased by 15% in birds reared under blue light compared to other lightning conditions. Thus, we concluded that blue light conditions resulted in elevating metabolic activity and accelerating pace of life in Japanese quails. It is assumed that the blue light-induced effects are probably due to inhibition of melatonin synthesis.

[The estimation of age-related sensitivity of the retinal pigment epithelium of Japanese quail (Coturnix japonica) to the light damage].

The effect of blue light damage (445-455 nm, 4 J/cm2) to retinal pigment epithelium (RPE) subcellular structures was investigated in 4 age risk groups (9, 25, 40 and 52 weeks) of Japanese quail Coturnix japonica by light and electron microscopy. The indicator of biological aging of RPE was age-related accumulation of lipofuscin granules: 5-6-fold increase in their quantity increasing by 5-6 times in quails at 52 weeks. The main photo-induced changes observed after 24 h of the photo radiation were located in the blood-retinal barrier, such as loss of homogeneity of Bruch's membrane, disorganization of basal processes, deformations of the nuclei and mitochondria shapes. Those effects ofphotobleaching were more expressed in young birds. But for the older 52-week age birds it was not so noticeable, because their retinal pigment epithelium structures had disorders which were similar to those in younger birds after photodamage.

[Specification of reflectometric measurement complex to evaluate optic density of macular pigments and concentration of phototoxic chemicals in retina].

Suggestion is to specify reflectometric measurement complex based on digital multisensor imaginery fundus-camera, in order to evaluate optic density of macular pigments and concentration of phototoxic chemicals in human retina. The authors presented a review of role played by macular pigments (zeaxanthine and lutein) in human eye viability, analyzed yellow spot as a protective light filter against harmful effects of short-wave light, increasing optic image quality in human eye and responsible for colour vision. Role of evaluating the individual density of macular pigments was stressed as a forecasting efficient criterion of occupational selection in operators performing visual tasks of detection, distance and dimensions measurement for remote objects, monitoring the changeable circumstances.

[Detection of carotenoids in the vitreous body of the human eye during prenatal development].

Carotenoids were found for the first time in the vitreous body of human eye during the fetal period from week 15 until week 28. Their maximum content was timed to week 16-22. No carotenoids were found the vitreous body of 31-week fetuses, as well as adult humans, which corresponds to the published data. It was shown using HPLC that chromatographic characteristics of these carotenoids correspond to those of lutein and zeaxanthin, characteristic pigments of the retinal yellow macula.

[Increase in visual acuity in poorly-sighted patients by using spectral filters]. / Povyshenie ostroty zreniia u slabovidiashchikh s pomoshch'iu spektral'nykh fil'trov.

Tinted eyeglasses were selected for 768 poor-sighted patients aged 5-86 years with various ocular diseases. The frequency of tinted glasses utilization by poor-sighted patients was as follows: filter O2 was the optimal for 38% patients, filters G2 and K4 for 16-18%, and G1 for 11% patients. Filter G1 improved visual acuity by 19%, filters G2 and K4-K5 by 23%; the highest increment of visual acuity was observed with O2 filter: by 27%. Filters of different spectral characteristics and density may be useful in the same underlying ophthalmic disease, which is explained by the underlying disease and the presence, combinations, and severity of concomitant ocular diseases.

Ionochromic properties of long-wave-sensitive cones in the goldfish retina: an electrophysiological and microspectrophotometric study.

Long-wave-sensitive (LWS) cone visual pigments are sensitive to the concentration of chloride ions and show a spectral shift to shorter wavelengths when exposed to low chloride levels. We have used the aspartate-isolated mass receptor potential of the electroretinogram (ERG) to establish whether the spectrally shifted cone pigment is functional. In the goldfish, Carassius auratus, the lambda(max) of the LWS porphyropsin is displaced from about 622 nm to around 606 nm when chloride is replaced by gluconate. The electrical response of the LWS cones (but not MWS cones and rods) is selectively and reversibly abolished by the removal of chloride ions. The effect is concentration dependent and a decrease to half the normal chloride ion concentration is sufficient to cause a decrease in the response.

[High resistance of the rat retina rods to hypoxia]. / O vysokoi ustoichivosti k gipoksii palochek setchatki organa zreniia beloi krysy.

The amplitude of photoreceptor potential was shown to be constant in hypoxia. Under this condition, the energy support of the photoreceptor potential seems to be realized through an anaerobic process rather than the oxidative phosphorylation. The effect of hypoxia was shown to manifest itself in a decrease of the sagged peak part of the photoreceptor potential occurring in response to bright flashes. Such changes of wave form are typical for the case when the rod intracellular potential decreases. The decrease of response amplitude to bright flashes shortens the light scale of the amplitude/light intensity curve.

Spectral filters in low-vision correction.

Coloured filters are used to protect the lens, retina and other ocular tissues against the hazard of light damage and to improve the quality of vision mainly in cases of ocular media opacities. Four types of yellow, amber and orange filters have been designed as tinted glasses, shields and colour covering of spectacles. They were tested on 15 adult patients with partial cataract and on 80 children with congenital pathology (i.e. macular hypoplasia, albinism, aphakia after congenital cataract). The majority of the children had nystagmus. The filters with particular spectral characteristics provide reduction of light intensity in the light-damaging range by at least a factor of five. Optimal filters were selected by examination of visual acuity, contrast frequency sensitivity, glare sensitivity and subjective selection by the patients. The effects of filters were: 11-43% increase in corrected visual acuity, 27-34% increase in contrast sensitivity function (CSF) for all frequencies and a marked reduction in glare sensitivity. All patients reported subjective improvement including reduction of photophobia, eye-strain and eye discomfort. It is concluded that coloured filters are able to contribute substantially to rehabilitation of low-vision patients.

[Prevention of visual fatigue in computer users by eyeglasses with spectral filters]. / Profilaktika zritel'nogo utomleniia u pol'zovatelei komp'iuterami s pomoshch'iu ochkov so spektral'nym fil'trom.

Color-contrast optic filters are developed for improving the color discriminating capacity of eyes exposed to video display terminals. These filters are applied as a coating on correcting or common glasses. Effects of such eyeglasses on visual functions accommodation, frequency-contrast sensitivity, and critical frequency of flashes fusion (CFFF) were studied in 23 PC users with visual acuity of 1.0 with correction. Wearing of eyeglasses with filters promoted shifting of the most distant point of clear vision further and increased the accommodation volume, contrast sensitivity at the low and decreased it at the medium and high frequencies. CFFF was not changed. Wearing of eyeglasses with filters for 4 h of working at a display caused shifting of the nearest and most distant points of clear vision in comparison with the control group with the accommodation volume unchanged and preserved the high contrast sensitivity at the mean and low frequencies during the entire period of work. No changes in CFFF were noted. After 4 weeks of using eyeglasses with spectral filters, 86.9% of volunteers noted an improvement of visual working capacity and 13.1% considered there was no difference. Hence, eyeglasses with spectral filters are recommended as an ophthalmological measure preventing visual fatigue during long work with video displays.

[Spectral filters as a method of therapeutic correction]. / Spektral'nye fil'try kak vid lechebnoi korrektsii.

Spectral filters were used for additional correction of vision in 67 patients: in 15 adults with initial cataracts (intensive yellow filter), 26 children with albinism (yellow-brown filter), 14 children with macular hypoplasia (orange filter), and 12 children with aphakia after removal of congenital cataracts (yellow filter). Selection of the filter density is carried out using a special method including visocontrastometry, examination of sensitivity to lateral light, and study of color perception thresholds. Use of filters resulted in improvement of the vision acuity by 43.5% in patients with initial cataracts, by 10% in those with albinism, by 20% in those with macular hypoplasia, and by 22% in those with aphakia; moreover, an improvement of the frequency-contrast characteristics was observed, as well as a reduction of photophobia, and a reduction of vision amplitude in patients with nystagmus. The possible applications of spectral correction are discussed.

[Extracellular photoreceptor potential of albino rats]. / Vnekletochnyi fotoretseptornyi potentsial beloi krysy.

In this study methodically simple model of mammalian's total rods photoreceptor potential obtained by the known methods of outside electrical activity suppression by barium ions and sodium aspartate is offered. The farmacological analysis of that potential with using of ions-blockers of the potential-dependent conductances demonstrated that the offered potential consisted of the same components as the known intracellular responses.

[The effect of anions on spectral properties of iodopsin and native cones in the frog retina (microspectrophotometric study)]. / Vliianie anionov na spektral'nye svoistva iodopsin v nativnykh kolobochkakh setchatki liagushki (mikrospektrofotometricheskoe issledovanie).

Absorption spectra of single outer segments of the frog Rana temporaria photoreceptors were registered. Effects of nitrate and chloride ions on spectral properties of cone and rod pigments were compared. These pigments proved to differ in structure of the native photoreceptor membrane and, therefore, in effect of hydrophile environment on the chromophore centrum. Substitution of chloride by nitrate ions led to the hypochromic shift of the cone absorption spectrum (20-25 nm) but does not affect the spectrum on case of rod pigment. The ionochromic behaviour of cone pigments resembles that of the light-sensitive halobacterium protein halorhodopsin, in native membrane. We suppose that the effect of anions on the chromophore centrum may be the cause of bathochromic shifts of absorption spectra of longwave-length retinal-containing pigments.