Strabismus: From 3 Different Sources
See squint.
See SQUINT.
(heterotropia) n. squint: abnormal alignment of the two eyes. The strabismus is most commonly horizontal – convergent strabismus (or esotropia) or divergent strabismus (exotropia) – but it may be vertical (hypertropia, in which the eye looks upwards, or hypotropia, in which it looks downwards). In rare cases both eyes look towards the same point but one is twisted clockwise or anticlockwise in relation to the other (cyclotropia). Usually strabismus is concomitant, i.e. the abnormal alignment of the two eyes remains fairly constant, in whatever direction the person is looking. Strabismus acquired by injury or disease is usually incomitant, i.e. the degree of misalignment varies in different directions of gaze. See also cover test; deviation; divergence; heterophoria.
A type of strabismus (squint) in which one or both eyes turns inwards relative to the other.... cross-eye
n. poor sight, not due to any detectable disease of the eyeball or visual system, known colloquially as lazy eye. In practice this strict definition is not always obeyed. For example, in toxic amblyopia, caused by tobacco, alcohol, certain other drugs, and vitamin deficiency, there is a disorder of the *optic nerve. The commonest type is amblyopia ex anopsia, in which factors such as squint (see strabismus), cataract, and other abnormalities of the optics of the eye (see refraction) impair its normal use in early childhood by preventing the formation of a clear image on the retina. This in turn leads to a cortical visual impairment.... amblyopia
a test used to detect a squint. The observer looks at a target object, one eye at a time being covered. If the uncovered eye deviates to focus on the target, then a squint is confirmed. The movement can be up, down, sideways, or a combination, depending on the type of squint (see strabismus).... cover test
n. a type of squint (see strabismus) in which the eye, when tested, tends to rotate slightly clockwise or anticlockwise.... cyclophoria
n. 1. (in ophthalmology) any abnormal position of one or both eyes. For example, if the eyes are both looking to one side when the head is facing forwards, they are said to be deviated to that side. Such deviations of both eyes may occur in brain disease. Deviations of one eye, such as *dissociated vertical deviation, come into the category of squint (see strabismus). 2. see sexual deviation.... deviation
(DVD) a condition in which one eye looks upwards when the amount of light entering it is reduced, e.g. when it is covered. The eye returns to its original position when the cover is removed. DVD is an acquired condition chiefly associated with infantile esotropia (convergent *strabismus). The deviation is dissociated since there is no movement of the focusing (i.e. uncovered) eye during the deviation or return phase.... dissociated vertical deviation
n. 1. (in ophthalmology) simultaneous abduction of the eyes. Divergence excess is a divergent squint (see strabismus) in which the eyes are deviated outwards more when looking in the distance than when looking at near objects. Divergence insufficiency is a convergent squint (see strabismus) in which the eyes are deviated slightly inwards only when looking in the distance. 2. (in ethics) a difference of opinion.... divergence
n. convergent squint (see strabismus).... esotropia
n. divergent squint (see strabismus).... exotropia
n. a tendency to squint. Normally both the eyes work together and look at the same point simultaneously, but if one eye is covered it will move out of alignment with the object the other eye is still viewing. When the cover is removed the eye immediately returns to its normal position. Most people have a small degree of heterophoria in which the covered eye turns outwards, away from the nose (exophoria; compare esophoria). Heterophoria may produce eyestrain because of the unconscious effort required to keep the two eyes aligned. See also strabismus.... heterophoria
n. see strabismus.... heterotropia
n. see strabismus.... hypertropia
n. see strabismus.... hypotropia
a type of squint (convergent *strabismus) that results from the use of the convergence mechanism to block or dampen down *nystagmus in an attempt to improve visual acuity.... nystagmus block syndrome
n. the practice of using nonsurgical methods, particularly eye exercises, to treat abnormalities of vision and of coordination of eye movements (most commonly strabismus (squint) and amblyopia). Orthoptics also includes the detection and measurement of the degree of any such abnormalities. —orthoptic adj. —orthoptist n.... orthoptics
n. special techniques practised by orthoptists (see orthoptics) for developing normal function of the macula (the most sensitive part of the retina), in people whose macular function has previously been disturbed because of strabismus (squint).... pleoptics
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