What's an eye stroke?
Recently I realised I couldn’t see out of part of my right eye. After visiting the doctor I was referred and told I had an eye stroke. What does this mean? Will my vision come back?
Dr Pearse Keane says:
Sudden painless loss of vision may occasionally be caused by an ‘eye stroke’. These typically occur when a small clot (an embolism) blocks an artery supplying the retina (the nerve tissue that lines the back of the eye). The medical term for an eye stroke is a retinal artery occlusion (RAO) – ‘occlusion’ means blockage.
When the clot blocks the main artery to the retina, it is called a central retinal artery occlusion (CRAO). This is the most severe form and typically leads to complete blindness in the eye. When the embolism blocks only a branch of the main artery, this is a branch retinal artery occlusion (BRAO). This may be what you experienced. It usually affects part of the vision in that eye – for example the upper or lower part. In some cases, there’s only a temporary blockage and vision returns quickly – this is often described as a ‘mini-stroke’.
People who develop sudden loss of vision should see an expert urgently. Go to your local optometrist (who would refer you to an ophthalmologist) or direct to A&E. If an eye stroke is diagnosed within four hours of it happening, it may be possible to dislodge the clot by massaging the eye and giving medications to lower the pressure in the eye. Unfortunately, most patients don’t get specialist help for 24 hours or more, which is too late for treatment.
Even if your vision can’t be restored, always seek medical advice after an eye stroke, as you are at increased risk of a stroke in your brain. You should be referred to a stroke clinic for specialist tests.
It’s also important to be monitored by an ophthalmologist for at least six months afterwards. This is because other complications, such as raised pressure in the eyes, can make the eye painful but can be treated if picked up early.
Meet the experts
Dr Pearse Keane is a Consultant Ophthalmic Surgeon at Moorfields Eye Hospital.
Co-written with Dr Christoph Kern who is an Ophthalmologist at Moorfields Eye Hospital.