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.