A case report of alternating anisocoria with associated nasal congestion
Reviewed by Claire Howard

The authors have described a group of healthy individuals who show alternating anisocoria, in a previous paper. In these cases, the pupil asymmetry alternates between eyes every few hours, with no observed instances when both pupils are equal in size. This paper presents a single case of one such individual who also exhibits a classic nasal cycle, described as alternating periods of nasal congestion and decongestion. Measurements of pupil and nasal asymmetry were reported at 21 different time points. The measurements were found to always synchronise with each other, such that greater nasal airflow was found on the same side as the larger pupil. The authors hypothesise that a common central oscillator may be responsible for co-modulating the sympathetic outflow to both nasal vessels and iris dilator muscles in some healthy individuals. This report describes observations made on just one individual subject and the question remains as to whether these findings can be applied more generally.

A case of synchronised pupillary and nasal cycling: evidence for a central autonomic pendulum?
Bremner FD, Nordstrom JG.
NEURO-OPHTHALMOLOGY
2017;41(5):241-6.