Rigid pupil

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Classification according to ICD-10
H57.0 Pupillary dysfunction
ICD-10 online (WHO version 2019)

A pupillary rigidity means the lack of a reaction of the pupil to a light stimulus, as well as the convergence miosis . There are three different forms:

In the case of absolute pupillary rigidity, the oculomotor nerve , which pulls from the brain to some inner and outer eye muscles, is interrupted in its transmission of stimuli. Damage to the parasympathetic part of the Ncl. accessorius nervi oculomotorii is sufficient to trigger absolute pupillary rigidity. Usually, however, it is damage to the entire nerve. The affected eye can see despite the nerve damage. The incidence of light leads to an indirect (consensual) constriction of the pupil in the healthy eye.

In amaurotic pupillary rigidity, there is a disturbance in the perception of the light stimulus. An eye that is completely blind does not deliver any stimulus to the brain that would cause the pupil to constrict. The cause is damage to the pupil sensory fibers in the optic nerve. The pupil itself and all nerves supplying it are intact. When the other, seeing eye is exposed to light, both pupils therefore narrow, as is the case with healthy people.

In the case of reflex pupillary rigidity, there is no reaction to light stimuli (usually on both sides), but the reaction to convergence is not. This is due to a disruption of the fibers between the pretectal region where reflective pathways to the pupillomotor Ncl. Accessorius nervi oculomotorii turn towards the latter core itself. The reaction to convergence is part of a neurophysiological reflex circuit, the so-called close-up triad . The reflex pupillary rigidity in neurolues is called the Argyll-Robertson sign .

Reflective pupillary rigidity is rare and should not be confused with the much more common pupillotonia .

See also

literature