ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
A term used to refer to either a total or a partial loss of COLOUR VISION which may be either inherited or acquired. The most common inherited colour vision deficiencies are present from birth and produce a partial loss of colour vision in about 8% of men and under 1 % of women. These are forms of DICHROMATIC COLOUR BLINDNESS (PROTANOPIA, DEUTERANOPIA, TRITANOPIA) which arise when one of the three light-absorbing pigments in the cones of the retina is missing, and the milder versions (PROTANOMALY, DEUTERANOMALY, TRITANOMALY) which occur when all three pigments are present but one is anomalous. Much more rarely, colour vision may be absent altogether as a result of an inherited disorder, as in ROD MONOCHROMACY in which all three cone pigments are functionally absent. Acquired colour vision disorders, which onset during the subject's lifetime, have a wide range of causes. They usually produce a relatively mild loss of colour vision, for example due to disease processes or pharmacological agents affecting the retina or optic pathways. These acquired colour vision disorders may affect both red-green and blue-yellow colour OPPONENT PROCESSES, although it is believed that blue-yellow colour vision is more vulnerable when the damage is to the receptoral layers of the retina (KOLLNER'S RULE). A complete loss of colour vision (ACHROMATOPSIA) is very rare and is likely to arise from damage to areas of the temporal lobe of the brain that are specialized for the encoding of colour.
The Problems
John Greene, Ian Bone in Understanding Neurology a problem-orientated approach, 2007
Visual acuity should be tested in each eye with a Snellen chart (for far vision) and a near reading card for near vision. Each assessment is recorded in a standard way. For neurological purposes it is important that the patient wears glasses that they have been prescribed, to correct any refractive error. If these are unavailable, then looking through a small pinhole in a piece of paper or card will eliminate major refractive errors. If patients are severely visually impaired, an assessment of whether they can see how many fingers the examiner is holding up, or can appreciate movements of the hand or a light shone in the eye, is performed. Colour vision is assessed using specialist colour charts known as Ishihara plates. These were designed to detect congenital colour vision disorders, but are also useful for acquired defects.
Endocrine Therapies
David E. Thurston, Ilona Pysz in Chemistry and Pharmacology of Anticancer Drugs, 2021
MPA is well absorbed orally, with blood levels peaking after 2–4 hours and a half-life of 12–17 hours. It can also be administered in a depot form (i.e., Depo-ProveraTM) by deep intramuscular injection (normally into the gluteal muscle) which provides a half-life of 40–50 days. As with most progestogens, side effects include GI disturbances (e.g., nausea), cardiovascular abnormalities (e.g., hypertension, palpitation, congestive heart failure), depression, fluid retention, breast and menstrual cycle irregularities in women, alopecia, sexual dysfunction, skin reactions, and weight changes. In addition to these general adverse effects, the glucocorticoid effects associated with MPA can lead to Cushingoid syndrome at higher doses. Also, rarely, vision disorders such as retinal thrombosis can occur, in which case treatment should be immediately discontinued. Medroxyprogesterone acetate should be avoided during conception or pregnancy, as genital malformations in the fetus may occur.
Relationships between certain individual characteristics and occupational accidents
Published in International Journal of Occupational Safety and Ergonomics, 2019
Mohammad Javad Jafari, Abdullah Barkhordari, Davood Eskandari, Yadollah Mehrabi
We conducted this study in 2016 on 450 frontline workers of the Arya Sasol Petrochemical Company in Bushehr, Iran, and applied a stratified random sampling technique to select the participants. Of the 450 participants, 404 (89%) completed and returned the standardized questionnaire, in which we asked the participants for personal data, including their birth date, height, weight, work experience (years in present job), education (no formal education/formal education), vocational safety training, smoking habit (non-smoker/smoker), regular intake of sedatives pills (yes, no), regular physical activities, vision disorders, hearing disorders and sleep disorders (defined as being <6 h sleep/day and/or not sleeping well and/or regular intake of sleep-inducing drugs). In the overall distribution of BMI, we defined workers with BMI between 30.0 and 39.9 (obesity categories I and II) as obese. We defined vision disorders as eye problems that may require treatment beyond prescription lenses, such as amblyopia, strabismus, color deficiency, nyctalopia and photophobia. We defined occupational injury as bodily damage resulting from work activity, whatever its consequence, which resulted from an accident at work and required sick leave of at least 1 day. To ensure an adequate number of occupational injuries, we covered a 2-year work period.
Early menarche in visually impaired girls: evidence and hypothesis of light-dark cycle disruption and blindness effect on puberty onset
Published in Chronobiology International, 2022
Jorge A. Barrero, Ismena Mockus
The effect of light stimulation on sexual development depends on the photic sensitivity of the individual. As a consequence, determining the extent of light perception loss becomes imperative when comparing the age at menarche in girls with different degrees of visual deficit. Since not every alteration of the visual acuity affects light perception (Schulze-Bonsel et al. 2006), the comparison of girls with NLP and girls with visual acuity lower than 20/200 or with reduced visual fields proves to be particularly useful in assessing the effect of light on sexual maturation. Most studies concluded that lower photic capability is associated with earlier menarche. However, the findings reported by Grivas et al. (2006) differ significantly, as they concluded that visually impaired women experienced delayed menarche. Among the main causes of vision disorders within their population under study, the authors reported lens abnormalities and oculomotor pathologies. In this sense, some uncertainty exists regarding these findings since it is unknown whether the lens abnormalities associated with diffraction problems and oculomotor pathologies could compromise light perception.
Who put the ‘paediatric’ in paediatric eye care?
Published in Clinical and Experimental Optometry, 2018
During infancy and childhood, the visual system is changing and is susceptible to its input, so paediatric eye care is important to detect and manage any anomalies that may affect visual development. Optometrists are the main providers of primary eye care in Australia. The competency standards for optometry in Australia and New Zealand require optometrists to be able to manage patients requiring vision therapy, specifically ‘a vision therapy for patients with amblyopia, strabismus and binocular vision disorders’ with a sound evidence base.2015 Guidance from Optometry Australia2016 indicates that optometrists are in a good position to diagnose and treat paediatric eye and vision abnormalities, and have a role in prevention, screening and referral for such conditions where appropriate. We should therefore consider that all optometrists are paediatric eye‐care providers, since optometry includes patients of any age.
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