Abnormal Dynamic Pupillometry Relates to Neurologic Disability and Retinal Axonal Loss in Patients With Multiple...

To assess alterations in quantitative dynamic pupil responses to light in relation to neurologic disability and retinal axonal loss in patients with multiple sclerosis (MS).

Twenty-five patients with relapsing-remitting MS and 25 healthy subjects were included in this cross-sectional study. Pupillary responses were measured with an infrared dynamic pupillometry unit, and peripapillary retinal nerve fiber layer (RNFL) thickness was measured with spectral-domain optical coherence tomography. Neurologic disability was assessed by the Expanded Disability Status Scale (EDSS). Patients with a history of optic neuritis (ON) within 6 months were excluded. Only the right eyes were assessed, except in 11 patients with a history of unilateral ON in whom both eyes were further analyzed to evaluate the effect of previous ON.

The initial pupil diameter (P = 0.003) and pupil contraction amplitude (P = 0.027) were lower in patients with MS compared with healthy controls. Initial pupil diameter correlated with EDSS score (ρ = -0.458; P = 0.021), and RNFL correlated with contraction latency (ρ = -0.524; P = 0.007). There were no significant differences in any of the pupil parameters between eyes with and without a history of ON, and between the ON and fellow eyes of the 11 patients with previous unilateral ON.

Dynamic pupillometry reveals significant alterations in pupillary light reflex responses associated with neurologic disability and retinal axonal loss, independent of previous ON.

Dynamic pupillometry is a simple, noninvasive tool that may be useful in detecting autonomic dysfunction in patients with MS.