Sendrowski, D P, Buker, E A, Gee, S S · Optometry and vision science : official publication of the American Academy of Optometry · 1997 · DOI
Researchers tested whether ME/CFS patients have unusually sensitive nerves that control pupil size, similar to what is seen in fibromyalgia. They applied eye drops to 29 ME/CFS patients and 33 healthy controls and measured how much the pupils dilated. The results showed no significant difference between the two groups, suggesting that ME/CFS patients do not have this type of nerve sensitivity.
Understanding whether ME/CFS involves abnormal sympathetic nervous system function could help identify a biological marker for diagnosis. This study tested a specific mechanism that had been hypothesized based on similarities between ME/CFS and fibromyalgia brain imaging patterns, providing evidence against one proposed pathophysiological pathway.
This study does not rule out sympathetic nervous system dysfunction in ME/CFS using other testing methods or measuring different aspects of sympathetic function. It only tests one specific type of nerve sensitivity in the pupil and cannot exclude other mechanisms of autonomic dysregulation that may occur in ME/CFS. Negative findings in a small sample do not definitively exclude the hypothesis for all patients.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
Spotted an error in this entry? Report it →