Vision loss

One of the effects of brain injury that has a major impact on daily living is changes in vision. Eyesight is something many of us depend on, and when a person experiences changing vision or vision loss, this can be scary and difficult. They also experience intense emotions related to the change or loss of their vision which can include depression, grief, and anger.

They will need to work with specialists such as neurologists and eye doctors (optometrists) to determine if the vision deficits they are experiencing are temporary or permanent. Since recovery takes a long time, it may be awhile before the medical team can determine what vision deficits are temporary and what are permanent.

If the person’s vision loss is long-term or permanent, ophthalmologist or optometrists may recommend corrective lenses, glasses or surgery. No matter what kind of vision problems your friend or family member is experiencing, they will need to learn new ways to complete tasks and coping mechanisms to help them adjust to their new situation. This could include working with an occupational therapist to set up their home environment as well as assisting with how to complete activities of daily living as independently as possible. They may also consider meeting with an optometrist that can teach them how to take care of and use their remaining vision.

In your role as a caregiver, you may have to help the person navigate the home environment, learn coping methods, or complete tasks they can no longer do.

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How the brain controls vision

For our vision to work properly, our brain must be able to complete the following functions:

  • The eyes must move together and focus on objects
  • Nerve receptors at the back of the eye (retina) must then send messages back along the optic nerve
  • The occipital lobe at the back of the brain must catch or capture these messages

The occipital lobe is the area of the brain that has the most control over vision. It processes the images we see, including patterns, shapes and colours. Damage to the occipital lobe can cause a range of vision problems, including blindness.

Other areas of the brain that contribute to vision functioning are the parietal lobe and the frontal lobe. The parietal lobe helps with navigation, depth perception, and how to move around objects. The frontal lobe is the decision-making part of the brain: it decides how to respond to the information supplied by other lobes. While they don’t control as much of our vision as the occipital lobe, they still play a part in correctly analyzing and responding to what we see. Damage to these lobes could lead to vision changes.

Vision problems after brain injury

Blurred vision
When there is damage to the visual cortex of the brain or to the eye and the nerve receptors, the person may experience blurry vision. This is also called visual acuity loss. It is similar to what people who need glasses experience. For example, their vision may be like someone who is near-sighted: objects close up may be clear and easy to see, while objects that are further away are blurred.

How blurred vision is treated depends on the degree of loss the person is experiencing. In some cases, glasses or surgery can help correct the problem. They will need to work with an optometrist to determine the best course of treatment.

Blurry vision is also a side effect of fatigue, which is common after brain injury. If they are getting tired or looking at something too long, objects may start to become blurred, their eyes may ache, or they may experience headaches. In this case corrective eyewear may not be helpful. The person should try resting their eyes and taking breaks during activities such as reading or using screens.

Sensitivity to light
Also known as photophobia or photosensitivity, sensitivity to light means the person has trouble adjusting to changes in lighting and struggle with bright lights such as fluorescents or sunlight.

Some tips that can help the person with sensitivity to light include:

  • Wearing tinted sunglasses to help reduce light and glare
  • Setting up appropriate lighting in your home and work environment that is low-impact on their eyes and brain
  • Avoiding technology with screens unless they have the proper backlighting and contrast. Using a screen in the dark can be hard on anyone’s eyes, and can be especially difficult for those with light sensitivity
Double vision after brain injury
Double vision (also known as diplopia) happens when the eyes don’t move exactly together, causing the person to see two of everything. This makes it hard to decide exactly where objects are. Someone with double vision is likely to bump into furniture, spill or drop items. It’s disorienting, and can cause a person to feel dizzy or nauseous.

If they are experiencing double vision sometimes an eye patch or glasses with prism lenses are prescribed. To reduce the risk of bumping into objects, items such as furniture need to stay in one place and not be moved. They can also try eye drops if they are experiencing dry eyes. Sometimes dryness causes strain which can cause double vision. Whatever the cause of double vision, they should see an ophthalmologist or optometrist if they are experiencing it.

A drooping eyelid
A drooping eyelid (also called ptosis) may block vision in the affected eye. This changes how the person sees, and it may take a while for their vision to adjust even if the drooping is temporary.

It’s hard to judge distances using only one eye. They may experience the following problems:

  • Dizziness
  • Miss seeing objects
  • Not know how fast objects are moving towards them, or how close they actually are
  • Have trouble pouring

Drooping eyelids can sometimes be treated with special glasses or surgery.

Vision loss
In some cases, a person may lose part or all of their vision. This can be temporary or permanent. Losing sight is incredibly difficult to cope with, and will require the person to adapt their daily lives. These adaptations are emotionally and mentally demanding and can impact the survivor’s wellbeing.

Our vision is broken up into fields. A good analogy is that our eye is like a pie, and each slice is a field of vision. The person with vision problems can lose slices of the pie: in other words, they have partial vision. The type of vision loss the person experiences is dependent on what pieces of the pie they lose. Types of vision loss associated with brain injury include hemianopia, quadranopsia , and complete monocular visual loss.

Hemianopia is blindness involving one-half of the visual field in both eyes. This means the person only has 50% vision in each eye. Depending on what part of the brain is damaged, the person could have vision on the same side of each eye (i.e. the left side), or on different sides (i.e. vision on the right side in the right eye and left side in the left eye) [1] . It could also mean they have vision in the top part of their eye, but not the bottom part. This is an example of partial blindness.

Quadranopsia is the same as hemianopia, except instead of losing 50% of vision, the person loses 25%. It is also classified as partial blindness. Other examples of partial blindness include losing peripheral vision or loss of vision from the centre of the eye moving outward [2].

Different people with partial blindness will retain different parts of their vision depending on their individual circumstances. When a person is experiencing partial loss of vision, they may experience some of the following challenges:

  • Suddenly notice objects that seem to appear or disappear as they can’t see that part of their environment
  • Bump into objects on the affected side
  • Not see food on the side of the plate on the affected side
  • Turn their head toward the unaffected side
  • Lose track of the last place on a page where they were reading or writing
  • Cut words in half when reading, which can make it hard to figure out what the word is

Legal blindness

In the definition provided by the Canadian National Institute for the Blind (CNIB), legal blindness is a level of blindness that has been defined by law to limit some activities for safety reasons, such as driving, or to determine eligibility for disability-related government programs and benefits. Someone is considered to be legally blind [3] when:

  • Visual acuity is 20/200 (or 6/60) or less in both eyes after correction, and/or
  • A visual field of 20 degrees or narrower

This means that the person can see very little or not at all.

Headaches and eye pain

Some effects of brain injury, including vision problems, can lead to headaches and eye pain. This includes eyes feeling dry, sore, and itchy. The muscles around the eyes may feel painful. They may also be experiencing headaches related to their vision problems when they are trying to focus on an object or task.

Headaches can be treated with medication (in moderation). If they are experiencing eye pain, they should speak with their optometrist or another member of the medical team. For at-home fixes, they can try:

  • Taking breaks with their eyes closed
  • Adjusting the lighting in your home
  • Using saline/tear solutions for dryness and itchy eyes

Returning to work with vision changes

If the person is interested in working, it’s possible to find a job or use adaptations that make working with vision loss possible.

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