A variety of symptoms may follow including drowsiness, vomiting, contra-lateral blindness caused by reflux of the drug to the optic chiasma, convulsions, respiratory depression or arrest, neurological deficit, and even cardiac arrest. These symptoms usually appear within about 5min. Oculocardiac reflex is the bradycardia which may follow traction on the eye. An effective local block ablates the oculocardiac reflex by providing afferent block of the reflex pathway. However the institution of the block and especially rapid distension of the tissues by the solution or by haemorrhage might occasionally provoke it.
Careful monitoring is essential for early detection.
Optic nerve atrophy . Optic nerve damage and retinal vascular occlusion may be caused by direct damage to the optic nerve or central retinal artery, injection into the optic nerve sheath or haemorrhage within the nerve sheath. These complications may lead to partial or complete visual loss.