Dissociated squint
| Classification according to ICD-10 | |
|---|---|
| H50.2 | Strabismus verticalis |
| ICD-10 online (WHO version 2019) | |
With dissociated strabismus height (also: dissociated vertical divergence or DVD ) refers to a usually bilateral alternating, but not necessarily symmetrical, vertical strabismus deviation of the eyes upward. It is not infrequently associated with an outward curl squint ( excyclotropy ). This form of squint represents a special type of eye muscle imbalance and cannot simply be explained by an over- or under-function of a straight or oblique vertical eye muscle . While the deviation phase is the occurrence of double vision very rare, but occasionally occurs.
This height deviation often occurs when reading small letters, decreasing concentration, daydreaming or fatigue. However, it can also be triggered by covering one eye, in which case the covered eye then drifts upwards. The decisive factor here does not seem to be the interruption of an unstable fusion , but rather the deprivation of light. If you then hold a color filter in front of the guide eye, the eye that has deviated upwards moves slowly downwards again under the cover. The same thing happens when the eye is uncovered again, whereby this downward movement was previously mistakenly mistaken for a fusion movement and the dissociating vertical squint was incorrectly referred to as alternating hyperphoria .
A dissociated vertical squint is an accompanying symptom of the so-called congenital squint syndrome in about 90% of cases . Since other vertical disturbances, for example a strabismus sursoadductorius , can also be present, it is essential to determine the most precise possible delimitation of the dissociated parts of a vertical squint angle from the associated, oblique-related impulses. This is particularly important for determining the correct dosage for a planned squint operation .
therapy
As a rule, a dissociated vertical squint is not treated surgically or only in very rare cases. It should also be borne in mind that although it does not go away on its own over the years, really problematic and difficult cosmetically disfiguring forms only occur in around 1–3% of cases. However, if indicated accordingly, a so-called suture operation on the superior rectus muscle has evidently proven to be the best option.
See also
literature
- Herbert Kaufmann: Strabismus . With the collaboration of W. de Decker et al., Stuttgart: Enke, 1986, ISBN 3-432-95391-7
