The Cambridge Colour Test: Reliability of discrimination trivectors in colour space
- Hasrod, Nabeela, Rubin, Alan
- Authors: Hasrod, Nabeela , Rubin, Alan
- Date: 2019
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/398903 , uj:33229 , Citation: Hasrod N. & Rubin A. 2019. The Cambridge Colour Test: Reliability of discrimination trivectors in colour space. Afr Vision Eye Health. 2019;78(1), a451. https://doi.org/10.4102/ aveh.v78i1.451 , ISSN: 2410-1516 (Online) , ISSN: 2413-3183 (Print)
- Description: Abstract: The reliable assessment of colour discrimination has become increasingly important as some ophthalmic diseases and systemic conditions manifest themselves via acquired impairments of colour vision. The Cambridge Colour Test (CCT) is a computerised procedure, developed using the basic principles of traditional pseudoisochromatic plates to evaluate colour function or discrimination. Aim: The study investigated reliability of the CCT, with emphasis on the Trivector subtest, which measures thresholds along the three protan, deutan and tritan confusion lines to probe the sensitivity of the long, medium and short wavelength cones...
- Full Text:
- Authors: Hasrod, Nabeela , Rubin, Alan
- Date: 2019
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/398903 , uj:33229 , Citation: Hasrod N. & Rubin A. 2019. The Cambridge Colour Test: Reliability of discrimination trivectors in colour space. Afr Vision Eye Health. 2019;78(1), a451. https://doi.org/10.4102/ aveh.v78i1.451 , ISSN: 2410-1516 (Online) , ISSN: 2413-3183 (Print)
- Description: Abstract: The reliable assessment of colour discrimination has become increasingly important as some ophthalmic diseases and systemic conditions manifest themselves via acquired impairments of colour vision. The Cambridge Colour Test (CCT) is a computerised procedure, developed using the basic principles of traditional pseudoisochromatic plates to evaluate colour function or discrimination. Aim: The study investigated reliability of the CCT, with emphasis on the Trivector subtest, which measures thresholds along the three protan, deutan and tritan confusion lines to probe the sensitivity of the long, medium and short wavelength cones...
- Full Text:
Chromatic properties of astigmatic eyes
- Evans, Tanya, Harris, William F.
- Authors: Evans, Tanya , Harris, William F.
- Date: 2018
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273659 , uj:29156 , Citation: Evans, T. & Harris, W.F. 2018. Chromatic properties of astigmatic eyes. African Vision and Eye Health, 77(1), a435. https://doi. org/10.4102/aveh.v77i1.435 , ISSN: 2410-1516 (Online) , ISSN: 2413-3183 (Print)
- Description: Abstract: Chromatic differences in power, refractive compensation, position and magnification have been described in the literature for Gaussian eyes. Aim: This article explores these definitions and defines chromatic properties for eyes that have astigmatic and decentred or tilted elements. Setting: Linear optics. Methods: The optical model is linear optics and makes use of the ray transference T. Results: Results are presented as either 2 × 2 matrices or 2 × 1 vectors. The dependence of the chromatic properties on the position of an object and the limiting aperture is explored and results are presented as independent of, or dependent on, object and aperture position. Apertures undergo both longitudinal and transverse shifts in position. The results are general and apertures may include pupils or pinholes, either surgically inserted inside the eye or held in front of the eye. Numerical examples are provided for Le Grand’s four-surface eye and an arbitrary astigmatic heterocentric four-surface eye.
- Full Text:
- Authors: Evans, Tanya , Harris, William F.
- Date: 2018
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273659 , uj:29156 , Citation: Evans, T. & Harris, W.F. 2018. Chromatic properties of astigmatic eyes. African Vision and Eye Health, 77(1), a435. https://doi. org/10.4102/aveh.v77i1.435 , ISSN: 2410-1516 (Online) , ISSN: 2413-3183 (Print)
- Description: Abstract: Chromatic differences in power, refractive compensation, position and magnification have been described in the literature for Gaussian eyes. Aim: This article explores these definitions and defines chromatic properties for eyes that have astigmatic and decentred or tilted elements. Setting: Linear optics. Methods: The optical model is linear optics and makes use of the ray transference T. Results: Results are presented as either 2 × 2 matrices or 2 × 1 vectors. The dependence of the chromatic properties on the position of an object and the limiting aperture is explored and results are presented as independent of, or dependent on, object and aperture position. Apertures undergo both longitudinal and transverse shifts in position. The results are general and apertures may include pupils or pinholes, either surgically inserted inside the eye or held in front of the eye. Numerical examples are provided for Le Grand’s four-surface eye and an arbitrary astigmatic heterocentric four-surface eye.
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Oscillatory thresholds and foveal and macular thickness using coherence tomography
- Authors: Humphreys, Amy , Rubin, Alan
- Date: 2018
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/281215 , uj:30256 , Citation: Humphreys A, Rubin A. Oscillatory thresholds and foveal and macular thickness using coherence tomography. Afr Vision Eye Health. 2018;77(1), a448. https://doi. org/10.4102/aveh.v77i1.448 , ISSN: 2410-1516 (Online) , ISSN: 2413-3183 (Print)
- Description: Abstract: Technology is evolving and advancing rapidly as is evident in the ophthalmic and optometric fields with the development of new equipment and software programs that assist in the examination of patients and diagnoses of ocular diseases. The new vision psychophysical software for measurements of oscillatory sensitivity (OS) is a recently developed program that can be used to assess visual ability at the fovea by establishing oscillatory thresholds (OT) and it is therefore necessary to assess the reliability and repeatability of this new software...
- Full Text:
- Authors: Humphreys, Amy , Rubin, Alan
- Date: 2018
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/281215 , uj:30256 , Citation: Humphreys A, Rubin A. Oscillatory thresholds and foveal and macular thickness using coherence tomography. Afr Vision Eye Health. 2018;77(1), a448. https://doi. org/10.4102/aveh.v77i1.448 , ISSN: 2410-1516 (Online) , ISSN: 2413-3183 (Print)
- Description: Abstract: Technology is evolving and advancing rapidly as is evident in the ophthalmic and optometric fields with the development of new equipment and software programs that assist in the examination of patients and diagnoses of ocular diseases. The new vision psychophysical software for measurements of oscillatory sensitivity (OS) is a recently developed program that can be used to assess visual ability at the fovea by establishing oscillatory thresholds (OT) and it is therefore necessary to assess the reliability and repeatability of this new software...
- Full Text:
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