What is a stroke?
A good blood supply is crucial for the brain to function as normal. A stroke, or cerebrovascular accident (CVA), is when the blood supply to part of the brain is cut off, usually due to a blockage but sometimes because of a brain haemorrhage. A transient ischaemic attack (TIA), sometimes referred to as a mini stroke, is when the symptoms last for less than 24 hours, because of a temporary blockage.
How does a stroke affect the eyes?
A stroke can affect the field of vision, where a part of the vision is ‘missing.’ The extent of the ‘missing’ part can be variable, and half (hemianopia) or quarter (quadrantanopia) of the vision could be missing when a person is looking straight ahead. Another common affect of a stroke is double vision (diplopia) or general blurred vision. There can also be vision processing issues, which means that common objects are not acknowledged or recognised (visual agnosia) even though they are seen. This can be particularly distressing for family members. Light-sensitivity (photophobia), dry eyes or nystagmus can also occur after a stroke. Some people can get partial recovery from the vision problems identified, but full recovery is unlikely.
How can these vision problems be treated?
For the loss in the field of vision, the first thing to do is to understand the side and extent of the vision loss. Appropriate precautions can then be taken. An example is if a person’s left field of vision is ‘missing,’ then all objects of interest, e.g. a cup of tea, should be placed at the person’s right hand side. Learning how to scan a whole area with the eyes before making any moves is also very helpful. This means doing things a little slower than before. Double vision can be relieved by the use of prisms in glasses. These can be stuck on or actually incorporated into the glasses lenses. In some cases, covering one eye up with a patch is advised to get rid of the double vision. Magnifiers may be used to enlarge reading material. Sunglasses can be worn to help against the light-sensitivity, and dry eyes can be treated with artificial tear drops. There is no treatment for nystagmus.
How can a person avoid having a stroke in the first place?
Looking after the general health is key. Having a healthy diet, exercising regularly, not smoking and not consuming alcohol all help reducing the risk of having a stroke.
It is important to have the eyes assessed after a stroke so that you can be aware of how it has affected the vision. New glasses (unless they have prisms) are unlikely to help, but you can get the right advice from your eye care practitioner.
Useful link: click here to learn how to identify if somebody is having a stroke, and what to do.