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Correction of hidden strabismus with glasses
Last reviewed: 02.07.2025
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Glasses with prismatic properties cause a deviation of the direction of the rays to the base of the prism. If the doctor includes wearing such lenses in the treatment, he can pursue the following goals:
- elimination of visual fatigue, optimization of vision in heterophoria;
- relief of diplopia due to impaired functioning of the eye muscles;
- restoration of simultaneous clear images in both eyes (in case of latent strabismus in childhood).
Most often, lenses with prismatic properties are used to correct heterophoria. But such treatment is not appropriate in all cases of latent strabismus. It is prescribed if the patient experiences excessive visual fatigue, pain in the eye area and above the bridge of the nose.
Correction involves the use of a prism with the base directed in the opposite direction from the visual deviation. This means that for patients with exophoria, the base is directed inward, for patients with hyperphoria - downward, etc. The degree of correction for latent strabismus is usually incomplete: the angle of prismatic deviation is always smaller than the heterophoric angle.
If the patient suffers from paresis of the eye muscles, prisms are placed in glasses intended for "near" vision - for example, for reading. The degree and linear direction from the "peak" to the "base" are determined by trial and error. Special devices consisting of a pair of prisms with variable power and seats for spherical and cylindrical lenses provide good assistance in this regard.
For correction purposes, prisms can be used to passively restore the image in both eyes or to activate fusion abilities. If passive correction of binocular vision is required, the degree and direction of the effect are selected using the Maddox scale. If the use of such a technique is impossible, a synoptophore (synopticoscope) is used - a special ophthalmological device. The use of prisms becomes appropriate with a small deviation (up to ten degrees) and relative stability of the angle. Prisms are most optimally used with slight vertical displacements.
If the goal of correction is to activate fusion abilities, then the lenses are used in patients with convergent strabismus with the base towards the bridge of the nose, and with divergent strabismus – with the base towards the temporal region. Such glasses should be worn for several hours daily, under regular supervision of the attending physician.
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