Strabismus is a state when one or both eyes alternatively deviate from the central axis resulting in disruption of binocular vision. With strabismus, the eyes look in different directions. As a result the vision system cannot focus the sight on the object. True strabismus differs from latent and false forms of strabismus.
Latent strabismus (heterophoria)
Latent strabismus (heterophoria) is caused by deficient symmetry in the operation of the eye moving muscles and is associated with deviation of one eye at the time when the affected person does not fixate sight on any object. This is particularly noticeable, when the person becomes lost in thought and separates himself from the surrounding reality.
Latent strabismus is detected by excluding one eye from the process of binocular vision. As latent strabismus is corrected by the act of binocular vision, it requires no treatment with the exception of cases when due to substantial latent strabismus, binocular vision is hampered, particularly at close distances. This results in visual fatigue, frequent headaches, etc. Prismatic glasses are prescribed in this case, or decentered corrective glasses, and sometimes surgery.
False strabismus develops due to the specific structure of the eyeball: in the event of a greater angle between the visual line and the optic axis there couyld be a false opinion on the presence of squinted eyes. This type of strabismus is determined by the fact that most people have an angle between the optic and visual axes. When this angle is small (within 3-4 degrees), the eyes are in parallel. But when the divergence between the visual and optic axes is greater (in some cases up to 10 degrees), then the center of the cornea is shifted to one or another side resulting in what seems to be strabismus. However, in this case binocular vision is retained. The asymmetry of the face and orbits may also create the impression of strabismus. False strabismus requires no treatment.
Ophthalmologists believe that not all deviations from binocular vision lead to the true deviation of the eyeball from the normal position. For this reason only obvious strabismus is considered to be a pathology requiring timely treatment.