Effect of digitally generated colored filters on Farnsworth-Munsell 100 hue test by red-green color vision-deficient observers

In this study, the effects of four different digitally generated colored filters on the Farnsworth-Munsell 100 hue test (100-hue test) are analyzed by red-green color-vision deficient (CVD) observers. We digitally simulate the colored filters based on the spectral transmittance of four colored filters, which have been used previously. Five red-green CVD observers are subjected to the 100-hue test on a monitor under nine filter conditions, which comprise one condition without filter and eight conditions with filters. The results suggest that a colored filter that transmits long wavelengths and absorbs medium wavelengths may improve the color discrimination performance of protans and deutans.

Discrimination of colors by red–green color vision-deficient observers through digitally generated red filter

Previous studies have shown that with the use of tinted lenses (or colored filters), individuals with red–green color vision deficiency (CVD) report an improvement in their performance on certain color vision tests. In this context, this study examines the effects of a digitally generated red-colored filter and identifies the mechanism mainly responsible for the changes in red–green CVD observers’ performance on a D-15 arrangement test performed using the filter. We simulate the red filter digitally with the spectral transmittance similar to that of the X-Chrom, which is a red-tinted lens. Fourteen red–green CVD subjects are subjected to the D-15 test on a computer monitor under four filter conditions, consisting of one condition without the filter and three conditions with the filter, corresponding to the opacity of the red filter. The results show that while the simulated red filter improves the performance of deutans to arrange the caps in the D-15 test, this is not the case for protans. In addition, considerations based on the human cone-contrast model enable us to identify that the improvement in deutan observers largely results from the increase in the luminance contrast between stimuli and a background. To summarize, the red filter simulated in this study induces different changes in the red–green CVD observer luminance contrast between the protan and deutan types, with the result that the performance of deuteranopes improves while that of protanopes deteriorates.

Effect of Colored Filters on PV Panels Temperature and Performance under Baghdad Meteorological Condition

In this work, the influence of colors of filters upon the photovoltaic panels rising temperature and electrical performance was studied under Baghdad Meteorological Condition. Basing on the energy analysis of a photovoltaic solar system and by using the photonic theory, the available energy on the PV plane system has been evaluated. Seven colored filters each with (85W) PV modules were used in this case study, to reveal the impact of colored filters upon the electrical productivity of PV panel with the variation in the temperature caused by these filters. There is the main issue of this work is to show how the performance of PV module by imposing colored filter and hence how and to how much improve it by reducing the cell temperature in hot climate. Outcomes showed that the PV technology is affected by the color filters. In other words, red filter gives light have least photons energy, and violet filter gives light have the most photons energy and green is between the two. So, red colors filter gives highest PV panel temperature comparative with others filters, while violet color filter was the lowest. PV module with the lowest temperature colored filter gives the best electrical performance than others.

Perceived effects of coloured overlays on reading material in persons with albinism

Persons with albinism often complain of glare when reading. They may therefore benefit from coloured filter overlays just as they benefit from tinted lenses. The purpose of this study was to assess the effectof coloured overlays on print perception in persons with oculocutaneous albinism (OCA). Fifty subjects were included in this study, their ages ranged from 12 to 31 years with a mean of 16.12 years (SD = ± 4.56 years). Following refraction and subsequent compensation for refractive errors, subjective perception of print was examined with the subject looking at the Wilkins® reading rate test chart with and without colored filter overlay/s. The subjects were asked to respond to questions previously used in a questionnaire by Wilkins (2001). The percentage frequencies of positive (beneficial) responses were used to decide whether or not a particular overlay would enhance reading performance. McNemar’s test was used to establish significant differences between responses to questions without and with overlays. All single overlays gave greater percentages of positive responses (92.0-97.2%) than without overlay (85.2%). The single overlay that provided the highest positive responses was blue (97.2%) and the least was purple (92.0%). All double overlays, except grey/grey (82.0%) gave greater positive responses than without overlay (85.2%). Aqua/blue gave the greatest positive responses (possible benefits) (97.2%), followed by rose/rose (96.8%). Comparing the responses without overlay with single and double overlays, the difference in responses to the five questions was only significant (p < 0.05) with regard to brightness of the surface. The results suggest that overlays provided a more glare-free reading surface than without an overlay. It was, therefore concluded that the best advantage of the coloured overlays was in glare reduction. Although this study showed that there were more subjects who preferred single blue and aqua/blue double overlays, inter-subject preference for overlays varied, therefore the best overlay should be established for every patient for whom overlay is to be prescribed.

Morphology and spectral absorption characteristics of retinal photoreceptors in the southern hemisphere lamprey (Geotria australis)

The morphology and spectral absorption characteristics of the retinal photoreceptors in the southern hemisphere lamprey Geotria australis (Agnatha) were studied using light and electron microscopy and microspectrophotometry. The retinae of both downstream and upstream migrants of Geotria contained two types of cone photoreceptor and one type of rod photoreceptor. Visual pigments contained in the outer segments of these three photoreceptor types had absorbance spectra typical of porphyropsins and with wavelengths of maximum absorbance (downstream/ upstream) at 610/616 nm (long-wavelength-sensitive cone, LWS), 515/515 nm (medium-wavelength-sensitive cone, MWS), and 506/500 nm (medium-wavelength-sensitive rod). A “yellow” photostable pigment was present in the myoid region of all three types of photoreceptor in the downstream migrant. The same short-wavelength-absorbing pigment, which prevents photostimulation of the beta band of the visual pigment in the outer segment, was present in the rods and LWS cones of the upstream migrant, but was replaced by a large transparent ellipsosome in the MWS cones. Using microspectrophotometric and anatomical data, the quantal spectral sensitivity of each photoreceptor type was calculated. Our results provide the first evidence of a jawless vertebrate, represented today solely by the lampreys and hagfishes, with two morphologically and physiologically distinct types of cone photoreceptors, in addition to a rod-like photoreceptor containing a colored filter (a cone-like characteristic). In contrast, all other lampreys studied thus far have either (1) one type of cone and one type of rod, or (2) a single type of rod-like photoreceptor.