RESUMEN
Sub-Tenon's block has a superior safety profile and life-threatening complications such as cardiovascular collapse and brainstem anaesthesia are extremely rare. We report a case of cardiorespiratory collapse following bilateral sub-Tenon's blocks at the conclusion of a laser photocoagulation procedure under general anaesthesia. The cause was most likely brainstem anaesthesia. We explore and discuss the likely mechanisms and other potential differential diagnoses. It highlights the importance of maintaining vigilance following an eye block. Attention should not falter upon completing a block or at the conclusion of a case, regardless of its type or safety profile. This case also illustrates how the presence of general anaesthesia may obscure and delay the diagnosis of brainstem anaesthesia.