There are few actual eye emergencies, but acute occlusion of the retinal artery is indeed recognised as an emergency because it is a potentially blinding event. We call this condition central retinal artery occlusion or CRAO and it not infrequently presents to accident and emergency departments and even to Clinica London.
Despite the seriousness and urgency of treating CRAO, ophthalmologists have based the treatment options on clinical custom with very little scientific evidence.
The visual prognosis with central retinal artery occlusion is often poor and current therapeutic practices are unfortunately unproven. Without sounding too alarmist, if any patient should have a sudden loss of vision that is possibly due to a retinal artery occlusion they should attend an accident and emergency/eye casualty department urgently. The patient should lay flat and take a dose of intravenous Acetazolamide to try and improve retinal vasculature perfusion.
Our management of acute occlusion of the central retinal artery has not changed in the last 30 years, and although there are potential benefits of super-selective intra-arterial fibrinolytic therapy, it still requires evaluation in a randomised control trial.
Although central retinal artery occlusion is blinding it is also fortunately quite rare. However, this makes it more difficult to do a randomised control trial. Ophthalmologists should follow up all cases of central retinal artery occlusion because the condition carries a risk of new blood vessel formation later with a condition called ocular rubeosis. Ocular rubeosis is a condition in which blood vessels grow on the iris and into the angle of the eye causing an acute, painful red eye from glaucoma.
At Clinica London, Mr Jaheed Khan and Professor Michel Michaelides see patients who have ocular vascular events whether they are an arterial occlusion or a venous occlusion. A CRAO usually affects the whole of the vision, however, a branch retinal artery occlusion affects part of the vision. The risks factors for arterial occlusions include hypertension and clot formation in the heart or narrowing of arteries in the neck – which need to be assessed to reduce the risk of further visual loss or occlusions in other arteries in the body which could cause heart attacks or strokes. It is therefore important that if you have had a central or branch retinal artery occlusion – that an ophthalmologist who is skilled in medical retina such as Clinica London’s Mr Jaheed Khan and Professor Michel Michaelides – follows up with you.