Editor,—The letter by Gao Lei et al 1 gives an erroneous impression that retrobulbar injection per se produces oculocardiac reflex (OCR). On the contrary, retrobulbar anaesthetic infiltration is a method of prophylaxis to prevent OCR in patients under general anaesthesia.2 In patients operated under retrobulbar anaesthesia, “heart rhythm and rate become stable once the block has taken effect; occasional ectopics or heart rate changes before this seemingly being due to the stimulus of needle prick or the adrenaline in the solution”.3 The author’s experience is the same as described in the last paragraph. Their definition of OCR as at least a 10% decrease in heart rate below relative baseline is arbitrary. In a previous well designed study, Mirakhur et al have taken bradycardia of 70 or less heart beats per minute at any time during surgery and persisting for more than 15 seconds as study criteria and OCR as slowing of heart rate by more than 20% or arrhythmia during traction irrespective of heart rate.4 They felt that smaller decreases in heart rate do not usually require treatment. The findings by Gao et al do not mention the duration of arrhythmias or duration of drop in heart rate. It has been observed that development of inherent endogenous β blockade occurs with increasing age. Therefore isolated heart rate …