Retrobulbar optic neuritis (NORB) is the damage to the optic nerve caused by inflammation. It causes a rapidly progressive and painful visual loss, often among young subjects. Diagnosis confirmation is important to start proper treatment, because a NORB is often the first symptom of multiple sclerosis. This diagnosis, based on a set of arguments, is difficult to define by a non-expert ophthalmologist.
The pupillary light reflex is a way to test the visual afferent pathways. If it is subject to a large inter-individual variability, the dynamics of the pupillary light reflex and its latency are more reproducible. An easy way to study the dynamics of the pupillary light reflex is to study the pupillary cycle time (PCT). In the case of NORB, elongation of the conduction in the visual afferent pathways related to demyelination plate increases the latency of the pupillary light reflex and decreases the frequency of the PCT.
Our hypothesis is that PCT dynamics measures would be a reliable indicator and easy to evaluate some pathologies affecting the integrity of the nerve. The validation of a decrease in the frequency of the PCT in NORB, compared to the frequency observed in subjects ophthalmological or neurological disease, could help developing methods to study the conduction of the visual pathways with portable devices used during the standard ophthalmologic consultation and quickly orientate patients to specialized centers.
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