Chen, Chih-Sheng, Cheng, Hui-Man, Chen, Hsuan-Ju et al. · Oncotarget · 2018 · DOI
This study found that people with dry eye syndrome (DES) are more likely to develop ME/CFS than those without dry eye problems. Researchers followed patients in Taiwan over many years and discovered that those with dry eye had about twice the risk of developing ME/CFS. Even after accounting for age, sex, and other health conditions, the increased risk remained significant.
This is one of the few studies investigating a potential link between dry eye syndrome and ME/CFS, two conditions that may co-occur in patients. If the association reflects shared biological mechanisms (such as autoimmune, inflammatory, or autonomic dysfunction), understanding this connection could improve diagnosis and help physicians recognize both conditions in affected patients.
This study demonstrates association, not causation—it does not prove that dry eye syndrome causes ME/CFS. The findings may reflect shared underlying causes (confounding), reverse causation (early ME/CFS symptoms causing dry eye), or simply greater healthcare-seeking behavior in patients with multiple symptoms. Without mechanistic data or symptom-level analysis, the biological basis of the relationship remains unclear.
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 →
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