Alphabet symptom
| Classification according to ICD-10 | |
|---|---|
| H50.- | Other strabismus |
| ICD-10 online (WHO version 2019) | |
Alphabet symptom is a term from strabology , a branch of ophthalmology . It is used to describe the fact that a horizontal squint can vary in size, depending on whether you are looking down, straight ahead or up. This difference is also called inconsistency .
description
Often, an alphabet symptom is associated with internal squint. An increase in the A- incomitance and a decrease in the squint deviation when looking up is described as a V- incomitance . Accordingly, when looking down , this means a decrease in the squint angle for the A- and its increase for the V-incomitancy. In addition to the A and V incomitances, there are also X , Y and λ incomitances with a corresponding change in the respective horizontal deviation. This shows that the progression of the angle changes when looking up and down does not necessarily have to be harmonious.
Furthermore, with A- and λ-incomitances there is often a lower position (hypotropia) of the adducted eye, with V- and Y-incomitances a corresponding higher position (hypertropia). These symptoms are also summarized under the terms strabismus deorsoadductorius or strabismus sursoadductorius , which can also be part of the so-called congenital strabismus syndrome .
root cause
Functional disorders of the oblique muscles of the eye are generally described as the cause . According to this, A and λ incomitances are mostly due to hyperfunctions of the Mm. obliqui superiores and / or sub-functions of the Mm. obliqui inferiores , while V and Y incomitances are associated with an underfunction of the upper and / or overfunction of the lower oblique eye muscles.
In addition to the over and under functions of the Mm. obliqui are occasionally caused by the straight vertical motors ( Mm. recti superiores and Mm. recti inferiores ).
Regardless of the respective concentration of the functional disorders on one muscle group, it can be assumed that the interaction of all vertical motors follows Hering's law of the same side innervation only very imperfectly .
therapy
A sensible form of therapy, if necessary, is a squint operation , which is usually performed on the Mm. obliqui is carried out, since an existing rotational squint (cyclotropy) can be better compensated here than with operations on the straight vertical motors.
literature
- Herbert Kaufmann (Ed.): Strabismus. With the collaboration of Wilfried de Decker et al. Enke, Stuttgart 1986, ISBN 3-432-95391-7 .
