Stroke-Induced Blindness: Understanding The Risks And Complications

Strokes can cause visual impairments, with up to two-thirds of stroke victims experiencing some form of vision loss. Vision loss can occur in one or both eyes, and it can be partial or complete. The impact of a stroke on vision depends on the size and location of the stroke, as different regions of the brain work together to control vision. Strokes can affect the visual pathways of the eye, causing various problems such as visual field loss, eye movement problems, and visual processing issues. While complete vision recovery may not be possible, specific therapies and eye exercises can help improve muscle control and vision, aiding in the rehabilitation process.

Visual field loss

The visual field refers to everything a person can see, including straight ahead (central vision) and out to the side (peripheral vision). Visual field loss means that a person is unable to see a section of their field of vision, usually because the vision areas of their brain have been damaged by the stroke. The eyes themselves are typically functioning normally, but the brain cannot process the images from one area of vision.

There are different types of visual field loss:

• Hemianopia: Loss of the left or right half of the visual field of both eyes. This is the most common type.
• Quadrantanopia: Loss of either the upper or lower quarter of the visual field.
• Scotoma: A small patch of vision loss, often near the centre of vision. This is a less common type of visual field loss.

Eye movement problems

Vision problems are quite common after a stroke, with up to two-thirds of people experiencing some changes to their vision. This is because a stroke occurs when a part of the brain is starved of oxygen and nutrients, and the eyes send visual information to different parts of the brain involved in seeing. If a stroke affects certain parts of the brain that are involved in processing and interpreting visual information, it can affect your sight.

There are various treatment options for eye movement problems after a stroke. Prisms and occlusion, or patching, can be used to eliminate double vision. Temporary prisms may be recommended initially, and once the double vision stabilizes, a permanent prism can be incorporated into the glasses lens. Alternatively, occlusion involves applying a frosting sticker to one lens of the glasses to block the vision in one eye partially or fully.

Visual hallucinations

A stroke occurs when blood that brings oxygen to the brain stops flowing, causing brain cells to die. Vision loss is common after a stroke, with up to 66% of stroke survivors experiencing some change to their vision. This is known as visual field loss and can include the loss of peripheral vision or central vision.

The hallucinations experienced by patients with CBS are often detailed and can include scenes of familiar places and people, animals, and objects. They can be in colour and may encompass the whole visual field. The hallucinations tend to be sporadic and brief, and patients typically understand that they are not real. In some cases, the hallucinations become more vivid when the patient closes their eyes.

Treatment for CBS can include addressing the underlying lesion or using drugs that block serotonin receptors, such as some antipsychotics. In some cases, drugs that enhance serotonin activity may be helpful, particularly in cases with predominant thalamic involvement.

Temporary vision loss as a warning sign

Temporary vision loss can be a sign of an impending stroke. It requires immediate medical attention. If you experience any of the following symptoms, seek the immediate attention of a medical professional:

• Loss of ability to move one side of the body
• Loss of ability to speak
• Disorientation
• Loss of vision in one eye

A TIA is a warning sign of a stroke, like chest pain is a warning sign of a heart attack. It occurs when not enough blood reaches a part of the brain, creating symptoms that then disappear on their own. Vision loss to either the left or right side of the visual field can be a symptom of a TIA.

Vision Loss After a Stroke

Vision issues after a stroke are more common than you might think. According to Stroke.org, up to 66% of stroke survivors experience some change to their vision. This can include:

• Inability to recognise objects or faces
• Colour vision deficits
• Difficulty perceiving certain types of motion
• Loss of peripheral vision
• Dry eye
• Sensitivity to light

Treatment

If you develop a sudden vision problem or loss, call 911 so you can get to the best place for care as soon as possible. Treatment for vision changes depends on their cause, and the only way to find out the cause is to go to the ER and have testing done, even if the symptoms have resolved.

Visual restoration therapy

Vision Restoration Therapy (VRT) is a therapeutic intervention for people who have suffered vision loss due to neurological brain damage, such as a stroke. It is the only FDA-cleared therapy for the restoration of lost vision due to neurological brain damage.

VRT is performed on a computer at home twice a day, six days a week for six months. During each session, the patient focuses on a central point displayed on the screen and responds every time they see light stimuli appear elsewhere on the screen. The therapy is monitored and updated monthly by clinical staff as the patient's vision improves.

VRT is designed to strengthen the synaptic function of residual cells that have survived following brain trauma such as a stroke. By repeated activation through the course of the therapy, patients strengthen their impaired visual functions and regain useful vision.

VRT can be used in conjunction with NeuroEyeCoach, a compensation therapy that addresses difficulties with eye movements and the ability to integrate visual information. These two therapies complement each other and are provided in one therapy suite to maximise patient benefit.

Frequently asked questions