Early detection and prevention of vision defects
Micha de Winter, Mariëlle Balledux, José de Mare, Ruud Burgmeijer in Screening in Child Health Care, 2018
Squint and amblyopia are the most frequent disorders found when screening the vision of young children and may be the first sign of structural visual disorders (Boermans 1981, Gehrmann-Bax et al. 1981, Loewer-Sieger et al. 1987). Strabismus or squint describes a deviation of the position of the eyes, whereby the visual axes of the two eyes do not intersect at the focal point (Van der Hell-de Haas, undated). Squint can be manifest (a clearly visible and constant squint) or latent. A latent squint is not clearly visible but can be demonstrated when the cooperation of the two eyes is interrupted. Estimates for the prevalence of squint vary from 1.5 to 7% with an average of some 5%. Prevalence increases up to about the age of four (Bayley et al. 1974, Ingram 1980, Feldmann et al. 1988, Van der Hell-de Haas, undated). Because squint produces two different images the child will always use only one of the two eyes or one of the eyes will get preference (usually the one with the better acuity of vision). As a consequence the functioning of the other eye will decrease, possibly resulting in amblyopia. Amblyopia (the so-called lazy eye) is said to exist when the acuity of one eye has diminished without demonstrable structural causes, or if the decrease of the visual acuity is disproportionate to the structural deviation (Swaak 1978).
Cranial Nerve Syndromes
John W. Scadding, Nicholas A. Losseff in Clinical Neurology, 2011
Diplopia may also arise from pathology of the ocular muscles, for example dysthyroid restrictive ophthalmopathy, or from diseases affecting the neuromuscular junction, for example myasthenia gravis. If there is a very slow onset and progression, particularly if this occurs early in childhood, there may be suppression of the image from the weak eye, amblyopia. This is often accompanied by a visible squint, strabismus. In a divergent squint, the eyes are deviated away from each other (wall-eyed), exotropia: in a convergent squint the eyes are turned towards each other (cross-eyed), esotropia. If one eye is obviously higher (above) the other, this is termed hypertropia, or below the other, hypotropia. A latent squint may be demonstrated by asking the patient to fix on an object and then covering each eye in turn. If the uncovered eye moves to fix on the target, a latent squint has been elicited.
SKILL Assess vision: acuity in children or illiterate adults
Sam Evans, Patrick Watts in Ophthalmic DOPS and OSATS, 2014
Vision assessment in pre-verbal children is challenging but important. The early detection of reduced vision is important so treatment to prevent the development of amblyopia can be started. The vision of very small infants is initially assessed by observation. The ability of a child to maintain central, steady and maintained (CSM) fixation is an indication of visual function, as is the ability to fix on and follow a target. The target should be bright and the room free of distractions. A child who objects particularly to the occlusion of one eye may have reduced vision in the fellow eye. Forced-choice preferential-looking tests may be used from birth, although their reliability increases as the infant gains head-position control. In young infants, these tests require considerable interpretive skill on the part of the examiner and should be used in conjunction with CSM and clinical observation to build an idea of the probable visual capacity of the child.
Adherence to home-based videogame treatment for amblyopia in children and adults
Published in Clinical and Experimental Optometry, 2021
Tina Y Gao, Joanna M Black, Raiju J Babu, William R Bobier, Arijit Chakraborty, Shuan Dai, Cindy X Guo, Robert F Hess, Michelle Jenkins, Yannan Jiang, Lisa S Kearns, Lionel Kowal, Carly S Y Lam, Peter C K Pang, Varsha Parag, Roberto Pieri, Rajkumar Nallour Raveendren, Jayshree South, Sandra Elfride Staffieri, Angela Wadham, Natalie Walker, Benjamin Thompson
Amblyopia, colloquially known as ‘lazy eye’, is a common neurodevelopmental visual condition that occurs in 1-3% of the population.1 Most forms of amblyopia are characterised by reduced visual acuity in one eye and abnormal, unbalanced binocular vision. Amblyopia is most commonly caused by childhood high anisometropia (large difference in refractive error between eyes), strabismus (misalignment of the eyes), or a combination of the two factors. In current standard clinical practice, amblyopia is treated in childhood with full-time wear of prescription glasses, followed by daily patching or atropine eye drops to penalise vision in the better-seeing eye for many months to years.2 These long duration therapies are usually delivered at home by parents or caregivers, as office-based delivery for such prolonged treatment is costly and impractical. However, home-based treatments for amblyopia are often associated with poor treatment adherence.3
Practice patterns in the management of amblyopia among optometrists in Ghana
Published in Strabismus, 2022
Hubert Osei Acheampong, David Ben Kumah, Emmanuel Kofi Addo, Akosua Kesewah Asare, Eldad Agyei-Manu, Abubakar Sadik Mohammed, Benjamin Baah-Konadu, Isaiah Osei Duah Junior, Prince Mintah, Samson Darrah, Kwadwo Owusu Akuffo
Amblyopia is clinically defined as a reduction in visual acuity in one or both eyes without any attributable underlying pathology.1,2 Globally, the prevalence of amblyopia is 1–5%3–5and remains the leading cause of monocular visual impairment in children,6,7 and a predominant cause of poor vision in the adult populations.8–10 Hence, an untimely diagnosis and delayed treatment/management of amblyopia may affect prognosis and result in visual impairment.11 Amblyopia reduces the quality of life of affected individuals and also limits their career choices (especially firefighters, air pilots, surgeons that require two functioning eyes).12–14 The understanding of amblyopia management and practice patterns within a population are critical toward standardization of treatments and improvement in the quality of care. Nonetheless, to date, no study has evaluated this area of clinical practice in Ghana.
The functional impact of amblyopia
Published in Clinical and Experimental Optometry, 2018
Ann L Webber
Amblyopia is second only to uncorrected refractive error as the most common cause of poor vision in children and young people.2006 With prevalence of approximately three per cent of the population,2013 amblyopia has significant costs to both the individual and community in terms of screening and treatment. While much has been reported about the visual characteristics of amblyopia, the natural history of the condition and appropriate detection and treatment strategies,2008 the functional disadvantage of amblyopia has only more recently been specifically explored, particularly in the childhood population in whom amblyopia is most often diagnosed and treated. Indeed, the ethical basis for detecting and treating amblyopia or its risk factors without evidence of disability was directly questioned in Snowden and Stewart‐Brown's 1997 review of the literature regarding effectiveness of preschool vision screening.1997 Snowden and Stewart‐Brown1997 noted that the literature at that time provided a ‘reasonable basis for generating plausible hypotheses about the ways in which the target conditions might disable people, but is insufficient to draw any firm conclusions about their impact on quality of life’.
Related Knowledge Centers
- Anisometropia
- Astigmatism
- Cataract
- Stereopsis
- Strabismus
- Visual Acuity
- Atropine
- Eye Examination
- Glasses
- Eyepatch