This is a retrospective study looking for an association between compressive optic neuropathy in thyroid eye disease (TED-CON) and obstructive sleep apnoea (OSA). One hundred and nine patients with thyroid eye disease were asked to complete a validated questionnaire designed to assess their likelihood of having OSA. Forty-two patients had TED-CON and 67 had TED without neuropathy (TED without CON). The prevalence of OSA risk in the TED-CON group was significantly higher (59%) than the TED without CON group (33%). The authors hypothesise that OSA, which is known to cause systemic inflammation, may be an exacerbating factor of thyroid eye disease. They postulate that treatment of OSA, which can reduce elevated cytokines which have been implicated in TED, may be a modifiable factor to decrease the severity of TED and the risk of CON. The authors now screen all their TED patients for OSA with the questionnaire. The finding of the strong association is very interesting, and although not proven as causal, should be considered in TED patients. A prospective interventional study proving causality would be welcome.