Detection threshold for the rod system was measured psychophysically in adult goldfish before and... more Detection threshold for the rod system was measured psychophysically in adult goldfish before and after exposure to constant illumination of 340 lux (91 microW/cm2) for 7 days. As shown in the previous paper, rod outer segment (ROS) length increases an average of 60% under these conditions. The present work shows that visual sensitivity also increases, in approximate proportion to the additional optical density predicted by the longer ROSs. These results are the first to show that exposure to constant light can enhance visual sensitivity. They imply further that detection threshold is related to ROS length. Apparently, the photopigment in the ROS tips that is normally shed on a daily basis retains its photon-catching ability.
Journal of the American Optometric Association, 1995
Intraocular pressure (IOP) measurements obtained with five commercially available portable tonome... more Intraocular pressure (IOP) measurements obtained with five commercially available portable tonometers (Keeler Pulsair 2000, Tomey Pro-Ton, Tono-Pen XL, Perkins, and Shiotz) were compared to IOPs measured with a Goldmann tonometer in order to predict whether instrument accuracy justified substitution of a portable instrument for the Goldmann in all or specific circumstances. A total of 31 patients (59 eyes) were assessed. The order of techniques was random except that in each case Goldmann tonometry was performed first and Shiotz tonometry was performed last. Examiners were masked to all other IOP measurements. Correlation and regression analyses were used to predict Goldmann IOP from the other portable tonometer readings. In addition, the difference in pressure readings was compared to mean pressure readings. Comparisons of means, correlations, regression equations, and box plots of difference scores were performed to determine which techniques were more accurate. The results varied...
Journal of the American Optometric Association, 1990
Visual information travels from the retina to visual cortical areas along at least two parallel p... more Visual information travels from the retina to visual cortical areas along at least two parallel pathways. In this paper, anatomical and physiological evidence is presented to demonstrate the existence of, and trace these two pathways throughout the visual systems of the cat, primate, and human. Physiological and behavioral experiments are discussed which establish that these two pathways are differentially sensitive to stimuli that vary in spatial and temporal frequency. One pathway (M-pathway) is more sensitive to coarse visual form that is modulated or moving at fast rates, whereas the other pathway (P-pathway) is more sensitive to spatial detail that is stationary or moving at slow rates. This difference between the M- and P-pathways is related to some spatial and temporal effects observed in humans. Furthermore, evidence is presented that certain diseases selectively comprise the functioning of M- or P-pathways (i.e., glaucoma, Alzheimer's disease, and anisometropic amblyopi...
The retinas of 63 goldfish were examined after varying durations of exposure to one of three envi... more The retinas of 63 goldfish were examined after varying durations of exposure to one of three environmental lighting conditions beginning before hatching: constant light (340 lux), cyclic light (12 hr 320 lux, 12 hr dark) and constant dark. Up to 8 months, no effects of constant light or dark on photoreceptor numbers or structure were apparent. Densities of rod and cone nuclei were normal and all retinal layers appeared normal by light microscopy. Exposure to constant light for 12 months or longer resulted in a reduction in rod density by 37%. Cone numbers were unaffected by constant light, even with exposures of 3 yr, and rod and cone outer segments were normal in length at 11-20 months under all environmental conditions. Due to poor survival, only one animal was available for quantitative examination from the group reared in constant dark 12 months or longer. Photoreceptor size and number in this retina were similar to those in the constant light condition. The results suggest that...
EDITOR: There is a significant amount of both linearly and partially polarised light in natural e... more EDITOR: There is a significant amount of both linearly and partially polarised light in natural environments due to surface reflections and refractions, in addition to scattering, including the well-known Rayleigh scattering of the short wavelength portion of the visible spectrum (including UV and near-UV) produced by natural sunlight. Haidinger was the first to describe the ability of humans to view polarised light. He observed pale-yellow figures in the partially polarised light from the sky that are now commonly referred to as Haidinger’s brushes. The characteristic blue-yellow rotating propeller subtends an area of approximately three degrees centred on the fovea with polarization direction parallel to the blue axis and perpendicular to the yellow axis. Gehrcke and Boehm found Haidinger’s brushes were more easily seen while viewing light through a filter that transmitted shortwavelength light. Goldschmidt described a device that is still used in the clinical assessment of Haidinger’s brushes that is composed of a rotating polarised filter with a short-wavelength transmission filter. Patients’ perceptions typically are the presence of rotating blue-yellow ‘brushes’ in the same direction as the rotating polariser that is centred on the fovea. Hochheimer and Kues suggested that the perception of Haidinger’s brushes is due to a blend of birefringence and dichroic effects found in the macular
Part of the Occupational Therapy Commons, and the Optometry Commons This Article is brought to yo... more Part of the Occupational Therapy Commons, and the Optometry Commons This Article is brought to you for free and open access by the School of Occupational Therapy at CommonKnowledge. It has been accepted for inclusion in Faculty Scholarship (OT) by an authorized administrator of CommonKnowledge. For more information, please contact
Vision disorders are the 4th most prevalent class of disability in the United States and the most... more Vision disorders are the 4th most prevalent class of disability in the United States and the most prevalent handicapping condition in childhood. Early detection of visual suppression increases the likelihood of effective treatment and decreases the negative impact of conditions such as amblyopia, which affects 2-3% of children and is the most common cause of monocular visual impairments in young and middle-aged adults. Researchers at the University of Missouri-St. Louis have developed the Q3D (Quantitative Three Dot) Test, a handheld device that quantitatively measures the amount of visual suppression in a patient. Able to detect very small impairments and changes in suppression, the Q3D can catch suppression earlier than current methods. Quantified measurement allows for tracking intervention progress over time.
For gray or achromatic objects, brightness is a relatively simple transformation where very low l... more For gray or achromatic objects, brightness is a relatively simple transformation where very low luminance levels are perceived as black and higher levels are perceived as white. For chromatic objects, the transformation is more complex, depending on color purity as well. This influence of color purity on a color’s perceived brightness is a well-established phenomenon known as the Helmholtz–Kohlrausch (H-K) effect. We investigated gender differences in the H-K effect by measuring brightness (via direct brightness matching [DBM]) and luminance (via heterochromatic flicker photometry [HFP]) at five wavelengths (450, 520, 560, 580, and 650 nm) perceived as blue, green, green-yellow, yellow, and red hues. We compared DBM/HFP ratios between 13 males and 18 females. Based on previous evidence of a female advantage in chromatic processes, we hypothesized that DBM/HFP ratios would be higher in female subjects. While HFP measures were essentially the same between male and female subjects, DBM...
Supplemental digital content is available in the text. SIGNIFICANCE Men earn at least 6.5% more t... more Supplemental digital content is available in the text. SIGNIFICANCE Men earn at least 6.5% more than women in their first full-time jobs as optometrists. For current salaries, the gender wage gap is more than 13%. This study details the gender wage gap that remains after controlling for practice ownership, residency training, and employer-defined full-time work. PURPOSE The purpose of this study was to measure the gender wage gap by region and practice type for full-time optometrists who did not complete a residency and do not own their practice. METHODS Participants completed an online survey, providing data for their first and current optometry positions and demographic information. Respondents who reported full-time employment in the United States, not completing a residency, and not owning their practice were selected for further analysis by census region and practice type. In each category, the gender wage gap was calculated. RESULTS In all regions and practice types, men were paid higher starting salaries than women. For current salaries, men were paid higher in almost all regions and practice types. The wage gap increased from starting salary to current salary, although not in all regions and practice types. CONCLUSIONS When practice ownership, residency completion, and full-time work are controlled for, there remains a difference in the pay received by men and women in optometry. The salary data presented in this study may help optometrists narrow the wage gap.
The slides for the panelists' presentations can be found by going to Presentations collection... more The slides for the panelists' presentations can be found by going to Presentations collection for the Missouri Technology Expo 2010: https://mospace.umsystem.edu/xmlui/handle/10355/9623
Detection threshold for the rod system was measured psychophysically in adult goldfish before and... more Detection threshold for the rod system was measured psychophysically in adult goldfish before and after exposure to constant illumination of 340 lux (91 microW/cm2) for 7 days. As shown in the previous paper, rod outer segment (ROS) length increases an average of 60% under these conditions. The present work shows that visual sensitivity also increases, in approximate proportion to the additional optical density predicted by the longer ROSs. These results are the first to show that exposure to constant light can enhance visual sensitivity. They imply further that detection threshold is related to ROS length. Apparently, the photopigment in the ROS tips that is normally shed on a daily basis retains its photon-catching ability.
Journal of the American Optometric Association, 1995
Intraocular pressure (IOP) measurements obtained with five commercially available portable tonome... more Intraocular pressure (IOP) measurements obtained with five commercially available portable tonometers (Keeler Pulsair 2000, Tomey Pro-Ton, Tono-Pen XL, Perkins, and Shiotz) were compared to IOPs measured with a Goldmann tonometer in order to predict whether instrument accuracy justified substitution of a portable instrument for the Goldmann in all or specific circumstances. A total of 31 patients (59 eyes) were assessed. The order of techniques was random except that in each case Goldmann tonometry was performed first and Shiotz tonometry was performed last. Examiners were masked to all other IOP measurements. Correlation and regression analyses were used to predict Goldmann IOP from the other portable tonometer readings. In addition, the difference in pressure readings was compared to mean pressure readings. Comparisons of means, correlations, regression equations, and box plots of difference scores were performed to determine which techniques were more accurate. The results varied...
Journal of the American Optometric Association, 1990
Visual information travels from the retina to visual cortical areas along at least two parallel p... more Visual information travels from the retina to visual cortical areas along at least two parallel pathways. In this paper, anatomical and physiological evidence is presented to demonstrate the existence of, and trace these two pathways throughout the visual systems of the cat, primate, and human. Physiological and behavioral experiments are discussed which establish that these two pathways are differentially sensitive to stimuli that vary in spatial and temporal frequency. One pathway (M-pathway) is more sensitive to coarse visual form that is modulated or moving at fast rates, whereas the other pathway (P-pathway) is more sensitive to spatial detail that is stationary or moving at slow rates. This difference between the M- and P-pathways is related to some spatial and temporal effects observed in humans. Furthermore, evidence is presented that certain diseases selectively comprise the functioning of M- or P-pathways (i.e., glaucoma, Alzheimer's disease, and anisometropic amblyopi...
The retinas of 63 goldfish were examined after varying durations of exposure to one of three envi... more The retinas of 63 goldfish were examined after varying durations of exposure to one of three environmental lighting conditions beginning before hatching: constant light (340 lux), cyclic light (12 hr 320 lux, 12 hr dark) and constant dark. Up to 8 months, no effects of constant light or dark on photoreceptor numbers or structure were apparent. Densities of rod and cone nuclei were normal and all retinal layers appeared normal by light microscopy. Exposure to constant light for 12 months or longer resulted in a reduction in rod density by 37%. Cone numbers were unaffected by constant light, even with exposures of 3 yr, and rod and cone outer segments were normal in length at 11-20 months under all environmental conditions. Due to poor survival, only one animal was available for quantitative examination from the group reared in constant dark 12 months or longer. Photoreceptor size and number in this retina were similar to those in the constant light condition. The results suggest that...
EDITOR: There is a significant amount of both linearly and partially polarised light in natural e... more EDITOR: There is a significant amount of both linearly and partially polarised light in natural environments due to surface reflections and refractions, in addition to scattering, including the well-known Rayleigh scattering of the short wavelength portion of the visible spectrum (including UV and near-UV) produced by natural sunlight. Haidinger was the first to describe the ability of humans to view polarised light. He observed pale-yellow figures in the partially polarised light from the sky that are now commonly referred to as Haidinger’s brushes. The characteristic blue-yellow rotating propeller subtends an area of approximately three degrees centred on the fovea with polarization direction parallel to the blue axis and perpendicular to the yellow axis. Gehrcke and Boehm found Haidinger’s brushes were more easily seen while viewing light through a filter that transmitted shortwavelength light. Goldschmidt described a device that is still used in the clinical assessment of Haidinger’s brushes that is composed of a rotating polarised filter with a short-wavelength transmission filter. Patients’ perceptions typically are the presence of rotating blue-yellow ‘brushes’ in the same direction as the rotating polariser that is centred on the fovea. Hochheimer and Kues suggested that the perception of Haidinger’s brushes is due to a blend of birefringence and dichroic effects found in the macular
Part of the Occupational Therapy Commons, and the Optometry Commons This Article is brought to yo... more Part of the Occupational Therapy Commons, and the Optometry Commons This Article is brought to you for free and open access by the School of Occupational Therapy at CommonKnowledge. It has been accepted for inclusion in Faculty Scholarship (OT) by an authorized administrator of CommonKnowledge. For more information, please contact
Vision disorders are the 4th most prevalent class of disability in the United States and the most... more Vision disorders are the 4th most prevalent class of disability in the United States and the most prevalent handicapping condition in childhood. Early detection of visual suppression increases the likelihood of effective treatment and decreases the negative impact of conditions such as amblyopia, which affects 2-3% of children and is the most common cause of monocular visual impairments in young and middle-aged adults. Researchers at the University of Missouri-St. Louis have developed the Q3D (Quantitative Three Dot) Test, a handheld device that quantitatively measures the amount of visual suppression in a patient. Able to detect very small impairments and changes in suppression, the Q3D can catch suppression earlier than current methods. Quantified measurement allows for tracking intervention progress over time.
For gray or achromatic objects, brightness is a relatively simple transformation where very low l... more For gray or achromatic objects, brightness is a relatively simple transformation where very low luminance levels are perceived as black and higher levels are perceived as white. For chromatic objects, the transformation is more complex, depending on color purity as well. This influence of color purity on a color’s perceived brightness is a well-established phenomenon known as the Helmholtz–Kohlrausch (H-K) effect. We investigated gender differences in the H-K effect by measuring brightness (via direct brightness matching [DBM]) and luminance (via heterochromatic flicker photometry [HFP]) at five wavelengths (450, 520, 560, 580, and 650 nm) perceived as blue, green, green-yellow, yellow, and red hues. We compared DBM/HFP ratios between 13 males and 18 females. Based on previous evidence of a female advantage in chromatic processes, we hypothesized that DBM/HFP ratios would be higher in female subjects. While HFP measures were essentially the same between male and female subjects, DBM...
Supplemental digital content is available in the text. SIGNIFICANCE Men earn at least 6.5% more t... more Supplemental digital content is available in the text. SIGNIFICANCE Men earn at least 6.5% more than women in their first full-time jobs as optometrists. For current salaries, the gender wage gap is more than 13%. This study details the gender wage gap that remains after controlling for practice ownership, residency training, and employer-defined full-time work. PURPOSE The purpose of this study was to measure the gender wage gap by region and practice type for full-time optometrists who did not complete a residency and do not own their practice. METHODS Participants completed an online survey, providing data for their first and current optometry positions and demographic information. Respondents who reported full-time employment in the United States, not completing a residency, and not owning their practice were selected for further analysis by census region and practice type. In each category, the gender wage gap was calculated. RESULTS In all regions and practice types, men were paid higher starting salaries than women. For current salaries, men were paid higher in almost all regions and practice types. The wage gap increased from starting salary to current salary, although not in all regions and practice types. CONCLUSIONS When practice ownership, residency completion, and full-time work are controlled for, there remains a difference in the pay received by men and women in optometry. The salary data presented in this study may help optometrists narrow the wage gap.
The slides for the panelists' presentations can be found by going to Presentations collection... more The slides for the panelists' presentations can be found by going to Presentations collection for the Missouri Technology Expo 2010: https://mospace.umsystem.edu/xmlui/handle/10355/9623
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