Vision problems after a stroke are quite common. If a stroke affects certain parts of the visual pathway or parts of the brain that are involved in processing and interpreting visual information, then this can affect the sight of the stroke affected.
What are the types of vision loss?
- Visual field loss: The visual field is the entire area that one can see when the eyes are fixed in one position. These are of two types :
a) Homonymous hemianopia is the loss of one half of the visual field in each eye.
b) Quadrantanopia is the loss of either the upper or lower quarter of the visual field. - Eye movement control: If the nerves that make the eyes move are damaged, then one may not be able to move the eyes to a certain position. A nerve that controls individual eye muscles may stop working, causing eye turning (strabismus) – commonly known as ‘crossed eyes’ or double vision (diplopia). Other problems with eye nerves can cause an eyelid to droop (ptosis), or the pupil of an eye to become bigger.
- Unsteady movement: The constant, unsteady movement of the eyes, also known as Nystagmus leads to movements that will be jittery and can be side to side, up and down or circular.
- Dry eyes: Problems with the nerves of the eyelid, the facial nerve or the muscles of the eyelid can cause dry eyes.
- Visual neglect: People with visual neglect are not aware of, and do not respond to, things on their stroke-affected side.
- Visual Agnosia: People with visual agnosia have difficulty recognizing familiar faces and objects.
How to overcome the vision problems?
- Optical therapy: This therapy helps the patient to position images in a way that the patient will be able to see them in the line of sight. This can also be helpful to correct double vision, depth perception, and other visual impairments from stroke.
- Eye movement therapy: Therapies focusing on eye movement help to train a patient’s eyes to move within one’s new visual scope. This type of therapy can also help strengthen and train the eye muscles for increased eye movement control.
- Visual restoration therapy (VRT): This therapy helps to stimulate the blind spots in a patient’s visual field.
An eye-specialist usually assesses the vision problems as elaborated above and can provide appropriate therapies. He/she needs to be told the stroke history of the patient.