Impaired pupillary light reflex indices in Orbital Apex Syndrome – A rare case report

Abstract

The clinical presentation of reduced pupillary responses in orbital apex syndrome is currently not well understood clinically. The pupillary light reflex (PLR) is determined using dynamic pupillometry. A newly diagnosed 35-year-old diabetic female patient had ocular symptoms including orbital pain and ptosis, but no visual loss. Cranial nerve autonomic impairment was identified with dynamic pupillometry and compared with cardiac autonomic activity using heart rate variability (HRV). PLR showed that pupil size and response were severely affected, with a small resting pupil size, and minimal response to a bright white light flash was seen, due to decreased sympathetic activity. However, HRV showed normal cardiac sympathetic activity. These findings suggest that orbital apex syndrome may lead to changes in pupil size and response due to compression of sympathetic fibers at the apex of the orbit. Quantitative PLR measurements help to reveal relevant information on anatomical reflex pathways.