The selection of lens materials for non-prescription personal protective equipment has been a rel... more The selection of lens materials for non-prescription personal protective equipment has been a relatively simple process and has its origins in many studies around the 1970s. The viable materials available at that time were tempered glass, hard resin (n = 1.50) and polycarbonate. The modern spectacle non-prescription eye protector of choice is inevitably hard coated polycarbonate, which has exemplary impact resistant properties. In the prescription lens area, there is a bewildering array of materials of various refractive indices with a variety of coatings. The selection of an ophthalmic lens has optical and cosmetic considerations ahead of impact resistance. In complying with the Australian/New Zealand standard on prescription eye protection, adequate impact resistance must rate as the foremost requirement, with optical and cosmetic considerations as important but lesser considerations. In this review, the evidence on impact resistance of the available materials is presented, the standards set for testing impact resistance are detailed and some guidance is provided for the selection of prescription eye protection materials.
Faculty of Health; Institute of Health and Biomedical Innovation, Mar 1, 2003
We investigated the effect of color-vision deficiency on reaction times and accuracy of identific... more We investigated the effect of color-vision deficiency on reaction times and accuracy of identification of traffic light signals. Participants were 20 color-normal and 49 color-deficient males, the latter divided into subgroups of different severity and type. Participants performed a tracking task. At random intervals, stimuli simulating standard traffic light signals were presented against a white background at 5° to right or left. Participants identified stimulus color (red/yellow/green) by pressing an appropriate response button. Mean response times for color normals were 525, 410, and 450 ms for red, yellow, and green lights, respectively. For color deficients, response times to red lights increased with increase in severity of color deficiency, with deutans performing worse than protans of similar severity: response times of deuteranopes and protanopes were 53% and 35% longer than those of color normals. A similar pattern occurred for yellow lights, with deuteranopes and protanopes having increased times of 85% and 53% respectively. For green lights, response times of all groups were similar. Error rates showed patterns similar to those of response times. Contrary to previous studies, deutans performed much worse than protans of similar severity. Actual or potential applications of this research include traffic signal design and driver licensing.
This chapter describes a survey of colour contingent tasks with regard to colours used, redundanc... more This chapter describes a survey of colour contingent tasks with regard to colours used, redundancy of coding, and significance of error, both safety and financial. From this, researchers identified the most critical issues on the basis that the worst case sets the colour vision testing and pass criteria needed. This was carried out at the New South Wales Fire Brigades Training College and selected fire stations in Sydney with the assistance of fire-fighters at those locations.
The Adams Desaturated D-15 was introduced as a test for acquired color vision defects. In this st... more The Adams Desaturated D-15 was introduced as a test for acquired color vision defects. In this study, the assessment of congenital color vision defects by the Adams Desat D-15 is considered.
Background: The Farnsworth Lantern (Falant) is an occupational color vision test intended to iden... more Background: The Farnsworth Lantern (Falant) is an occupational color vision test intended to identify people with significant red-green color deficiency who are unable to name aviation, marine or railway signal lights correctly. The colors shown are white, green and red selected to be within protan and deutan isochromatic zones. Hypothesis: The Falant grades the severity of color deficiency and identifies subjects with different types of deficiency. Method: 270 color deficiency subjects (diagnosed with the Neitz anomaloscope) were examined. A subset of 108 subjects also completed the Farnsworth D15 and the Farnsworth-Munsell 100 hue test. Results: All dichromats and 75% of anomalous trichromats failed the Falant. The mean error score of dichromats was greater than that anomalous trichromats, but errors were made in a similar number of qualitative color naming categories. The range of Falant error scores was continuous with no demarkation between the criteria for pass and fail. It was not possible to identify anomalous trichromats likely to pass the Falant from the size of the anomaloscope matching range or from the results of Farnsworth-Munsell tests. Conclusions: People with severe red-green color deficiency fail the Falant, but neither the type nor the severity of color deficiency can be determined either from the qualitative results or from the error score.
The importance of testing children's color vision, partic... more The importance of testing children's color vision, particularly to identify color vision deficiencies at an early age, has long been agreed on by teachers and color vision researchers and healthcare workers. The classic color vision tests were not necessarily developed for children's cognitive abilities, even though they are commonly used to assess children's color vision. Although, in the past, psychologists have studied color seriation abilities of children, they have not necessarily chosen isoluminous stimuli, which would minimize brightness cues. This investigation was designed to assess the ability of children to seriate a gray series. Tests were constructed in the form of the Farnsworth-Munsell style of arrangement test with constant intervals of metric lightness (CIE L*). Four intervals (DeltaL* = 15, 10, 5, and 3) were used. The child was instructed to arrange the colors from darker to lighter (or vice versa). Errors were not made on the DeltaL* = 15 series. Only isolated errors were made on the DeltaL* = 10 series. Errors were made on the DeltaL* = 5 series that diminished with age to nil in the older groups. Errors were made on the DeltaL* = 3 series at all ages studied, which also diminished with increasing age. Children aged 5 to 12 have sufficiently grasped the concept of seriation. They are able to complete a series with DeltaL* = 5, hence are capable of performing color arrangement tests with similar color differences such as the Lanthony New Color Test and the Farnsworth-Munsell D-15. Given the large number of errors made on DeltaL* = 3 series, it may be concluded that children's performance on the 100-hue test, at least to the age of 12 years, could be unduly influenced by non-color vision factors.
Chromatic, spatial, and temporal losses of sensitivity were measured in 15 eyes of 10 patients wi... more Chromatic, spatial, and temporal losses of sensitivity were measured in 15 eyes of 10 patients with recovered optic neuritis. Chromatic sensitivities (for both red-green and blue-yellow) were measured using color-mixture thresholds; the chromatic sensitivity loss was classified as "selective" if it was significantly greater than the achromatic loss. Spatial and temporal sensitivities were measured with contrast sensitivity functions and flicker modulation sensitivity, respectively; these losses were classified as selective if the losses at high (spatial or temporal) frequencies were significantly greater (or significantly less) than losses at low frequencies. All patients had central fixation and were optically corrected carefully. In 1 eye, selective losses of sensitivity for red-green and blue-yellow were combined with a selective loss of sensitivity at high spatial (but not temporal) frequencies. This type of loss may indicate a selective loss of small axons in the optic nerve. The 8 other eyes that showed significant losses were generally nonselective in their chromatic, spatial, and temporal losses; this may indicate a nonselective loss of small and large axons.
Specific deficits in the processing of transient visual stimuli have been identified in reading d... more Specific deficits in the processing of transient visual stimuli have been identified in reading disabled children. It has, separately, been suggested that suitably chosen coloured lenses can be used to assist reading disabled children but this is controversial. To assess an hypothesis as to how coloured lenses might remediate visual processing, this study compared the visual perceptual grouping effects of eighteen disabled readers with those made by eighteen good readers of the same age. Perceptual grouping effects were obtained for each child under a normal condition and wearing blue, yellow, grey, red and green optical framed lenses. The results replicated previous work in demonstrating a larger grouping effect for the disabled readers, and it was suggested that this finding was consistent with the presence of a transient deficit in these children. Comparison of the grouping effects obtained using the coloured lenses showed that although there was no significant impact on the performances of the disabled readers, the blue lens significantly increased the size of the grouping effect for the good readers. The presence of the blue lens decreased the activity initiated by stimulation of the red and green cones relative to the level of activity initiated by blue cone stimulation. As blue cone initiated activity appears to play little part in the transfer of acuity information, the presence of the blue lens could depress performance in a normal visual system by decreasing the level of acuity information transfer (i.e., the information required for efficient selective attention sorting and minimizing the grouping effect).(ABSTRACT TRUNCATED AT 250 WORDS)
Color vision in four meridians in the visual field was investigated to the limits of the absolute... more Color vision in four meridians in the visual field was investigated to the limits of the absolute field using iso-luminous colors generated on a color television system following the technique previously described (Chioran et al., 1985; Sellers et al., 1986). Iso-luminous colors are especially useful in the peripheral visual field where luminance increments have relatively lower thresholds and hinder investigation of color vision systems. Two normal subjects were investigated (only one fully). Red-green and blue-yellow discrimination were demonstrated to within about 10° of the absolute field. No effects of rod intrusion were evident and the iso-luminous colors did not alter beyond an initial change in the first 5° where the color and luminance thresholds are similar in magnitude. Thus color vision must be considered trichromatic over the whole of the visual field. At small eccentricities the four meridians performed similarly but with increasing eccentricity marked asymmetries exist. By increasing stimulus size it was possible to produce thresholds equivalent to a 1o stimulus presented foveally. However, the red-green thresholds require a greater increase in stimulus size to achieve foveal-like performance than the blue-yellow or luminance thresholds at the same eccentricity. Thus the cortical magnification must differ for each mechanism. On the basis of the results, the concept of a retina having trichromatic, dichromatic and monochromatic zones must be replaced by one of a thoroughly trichromatic retina.
The selection of lens materials for non-prescription personal protective equipment has been a rel... more The selection of lens materials for non-prescription personal protective equipment has been a relatively simple process and has its origins in many studies around the 1970s. The viable materials available at that time were tempered glass, hard resin (n = 1.50) and polycarbonate. The modern spectacle non-prescription eye protector of choice is inevitably hard coated polycarbonate, which has exemplary impact resistant properties. In the prescription lens area, there is a bewildering array of materials of various refractive indices with a variety of coatings. The selection of an ophthalmic lens has optical and cosmetic considerations ahead of impact resistance. In complying with the Australian/New Zealand standard on prescription eye protection, adequate impact resistance must rate as the foremost requirement, with optical and cosmetic considerations as important but lesser considerations. In this review, the evidence on impact resistance of the available materials is presented, the standards set for testing impact resistance are detailed and some guidance is provided for the selection of prescription eye protection materials.
Faculty of Health; Institute of Health and Biomedical Innovation, Mar 1, 2003
We investigated the effect of color-vision deficiency on reaction times and accuracy of identific... more We investigated the effect of color-vision deficiency on reaction times and accuracy of identification of traffic light signals. Participants were 20 color-normal and 49 color-deficient males, the latter divided into subgroups of different severity and type. Participants performed a tracking task. At random intervals, stimuli simulating standard traffic light signals were presented against a white background at 5° to right or left. Participants identified stimulus color (red/yellow/green) by pressing an appropriate response button. Mean response times for color normals were 525, 410, and 450 ms for red, yellow, and green lights, respectively. For color deficients, response times to red lights increased with increase in severity of color deficiency, with deutans performing worse than protans of similar severity: response times of deuteranopes and protanopes were 53% and 35% longer than those of color normals. A similar pattern occurred for yellow lights, with deuteranopes and protanopes having increased times of 85% and 53% respectively. For green lights, response times of all groups were similar. Error rates showed patterns similar to those of response times. Contrary to previous studies, deutans performed much worse than protans of similar severity. Actual or potential applications of this research include traffic signal design and driver licensing.
This chapter describes a survey of colour contingent tasks with regard to colours used, redundanc... more This chapter describes a survey of colour contingent tasks with regard to colours used, redundancy of coding, and significance of error, both safety and financial. From this, researchers identified the most critical issues on the basis that the worst case sets the colour vision testing and pass criteria needed. This was carried out at the New South Wales Fire Brigades Training College and selected fire stations in Sydney with the assistance of fire-fighters at those locations.
The Adams Desaturated D-15 was introduced as a test for acquired color vision defects. In this st... more The Adams Desaturated D-15 was introduced as a test for acquired color vision defects. In this study, the assessment of congenital color vision defects by the Adams Desat D-15 is considered.
Background: The Farnsworth Lantern (Falant) is an occupational color vision test intended to iden... more Background: The Farnsworth Lantern (Falant) is an occupational color vision test intended to identify people with significant red-green color deficiency who are unable to name aviation, marine or railway signal lights correctly. The colors shown are white, green and red selected to be within protan and deutan isochromatic zones. Hypothesis: The Falant grades the severity of color deficiency and identifies subjects with different types of deficiency. Method: 270 color deficiency subjects (diagnosed with the Neitz anomaloscope) were examined. A subset of 108 subjects also completed the Farnsworth D15 and the Farnsworth-Munsell 100 hue test. Results: All dichromats and 75% of anomalous trichromats failed the Falant. The mean error score of dichromats was greater than that anomalous trichromats, but errors were made in a similar number of qualitative color naming categories. The range of Falant error scores was continuous with no demarkation between the criteria for pass and fail. It was not possible to identify anomalous trichromats likely to pass the Falant from the size of the anomaloscope matching range or from the results of Farnsworth-Munsell tests. Conclusions: People with severe red-green color deficiency fail the Falant, but neither the type nor the severity of color deficiency can be determined either from the qualitative results or from the error score.
The importance of testing children's color vision, partic... more The importance of testing children's color vision, particularly to identify color vision deficiencies at an early age, has long been agreed on by teachers and color vision researchers and healthcare workers. The classic color vision tests were not necessarily developed for children's cognitive abilities, even though they are commonly used to assess children's color vision. Although, in the past, psychologists have studied color seriation abilities of children, they have not necessarily chosen isoluminous stimuli, which would minimize brightness cues. This investigation was designed to assess the ability of children to seriate a gray series. Tests were constructed in the form of the Farnsworth-Munsell style of arrangement test with constant intervals of metric lightness (CIE L*). Four intervals (DeltaL* = 15, 10, 5, and 3) were used. The child was instructed to arrange the colors from darker to lighter (or vice versa). Errors were not made on the DeltaL* = 15 series. Only isolated errors were made on the DeltaL* = 10 series. Errors were made on the DeltaL* = 5 series that diminished with age to nil in the older groups. Errors were made on the DeltaL* = 3 series at all ages studied, which also diminished with increasing age. Children aged 5 to 12 have sufficiently grasped the concept of seriation. They are able to complete a series with DeltaL* = 5, hence are capable of performing color arrangement tests with similar color differences such as the Lanthony New Color Test and the Farnsworth-Munsell D-15. Given the large number of errors made on DeltaL* = 3 series, it may be concluded that children's performance on the 100-hue test, at least to the age of 12 years, could be unduly influenced by non-color vision factors.
Chromatic, spatial, and temporal losses of sensitivity were measured in 15 eyes of 10 patients wi... more Chromatic, spatial, and temporal losses of sensitivity were measured in 15 eyes of 10 patients with recovered optic neuritis. Chromatic sensitivities (for both red-green and blue-yellow) were measured using color-mixture thresholds; the chromatic sensitivity loss was classified as "selective" if it was significantly greater than the achromatic loss. Spatial and temporal sensitivities were measured with contrast sensitivity functions and flicker modulation sensitivity, respectively; these losses were classified as selective if the losses at high (spatial or temporal) frequencies were significantly greater (or significantly less) than losses at low frequencies. All patients had central fixation and were optically corrected carefully. In 1 eye, selective losses of sensitivity for red-green and blue-yellow were combined with a selective loss of sensitivity at high spatial (but not temporal) frequencies. This type of loss may indicate a selective loss of small axons in the optic nerve. The 8 other eyes that showed significant losses were generally nonselective in their chromatic, spatial, and temporal losses; this may indicate a nonselective loss of small and large axons.
Specific deficits in the processing of transient visual stimuli have been identified in reading d... more Specific deficits in the processing of transient visual stimuli have been identified in reading disabled children. It has, separately, been suggested that suitably chosen coloured lenses can be used to assist reading disabled children but this is controversial. To assess an hypothesis as to how coloured lenses might remediate visual processing, this study compared the visual perceptual grouping effects of eighteen disabled readers with those made by eighteen good readers of the same age. Perceptual grouping effects were obtained for each child under a normal condition and wearing blue, yellow, grey, red and green optical framed lenses. The results replicated previous work in demonstrating a larger grouping effect for the disabled readers, and it was suggested that this finding was consistent with the presence of a transient deficit in these children. Comparison of the grouping effects obtained using the coloured lenses showed that although there was no significant impact on the performances of the disabled readers, the blue lens significantly increased the size of the grouping effect for the good readers. The presence of the blue lens decreased the activity initiated by stimulation of the red and green cones relative to the level of activity initiated by blue cone stimulation. As blue cone initiated activity appears to play little part in the transfer of acuity information, the presence of the blue lens could depress performance in a normal visual system by decreasing the level of acuity information transfer (i.e., the information required for efficient selective attention sorting and minimizing the grouping effect).(ABSTRACT TRUNCATED AT 250 WORDS)
Color vision in four meridians in the visual field was investigated to the limits of the absolute... more Color vision in four meridians in the visual field was investigated to the limits of the absolute field using iso-luminous colors generated on a color television system following the technique previously described (Chioran et al., 1985; Sellers et al., 1986). Iso-luminous colors are especially useful in the peripheral visual field where luminance increments have relatively lower thresholds and hinder investigation of color vision systems. Two normal subjects were investigated (only one fully). Red-green and blue-yellow discrimination were demonstrated to within about 10° of the absolute field. No effects of rod intrusion were evident and the iso-luminous colors did not alter beyond an initial change in the first 5° where the color and luminance thresholds are similar in magnitude. Thus color vision must be considered trichromatic over the whole of the visual field. At small eccentricities the four meridians performed similarly but with increasing eccentricity marked asymmetries exist. By increasing stimulus size it was possible to produce thresholds equivalent to a 1o stimulus presented foveally. However, the red-green thresholds require a greater increase in stimulus size to achieve foveal-like performance than the blue-yellow or luminance thresholds at the same eccentricity. Thus the cortical magnification must differ for each mechanism. On the basis of the results, the concept of a retina having trichromatic, dichromatic and monochromatic zones must be replaced by one of a thoroughly trichromatic retina.
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