Primer on Stroke-related Vision Loss

You push open the heavy oak doors of the pub and are instantly hit with a barrage of jovial sounds mixed with the scent of a strong alcohol and sweat cocktail. 

Scanning round the establishment, you quickly locate your friends and make your way to the empty seat left, you presume, for you. 

And then the drinks start. 

After a few rounds or more, you start to notice a numbing sensation on the left side of your body. Your friends comment on how your left eye and mouth are drooping. You try to say that something seems wrong, but it all sounds garbled and nonsensical.

At first, you blame it on the alcohol, but then you realise that you can no longer move your left arm. You start panicking. 

You’re having a stroke. 

The next thing you remember is waking up in a hospital room. It’s dark and you’re alone. 

You mentally check over yourself. Arm works. Face seems to be as expressive as ever. Mental calculations are tough, but you were never good at them anyway. Words sound clear enough. 

Footsteps gradually increase in volume and you realise that they are coming to you. 

You quickly close your eyes as light suddenly invade your eyes. As you become accustomed, you tentatively open your eyes. 

But you can only see half of what you would normally see. 

One side of your vision is gone.

 

Strokes occur when a part of the brain is deprived of oxygen. It is life threatening and can leave the victim/survivor with a series of conditions, ranging from mental to physical to cognitive. 

There are also various visual problems that can arise. Here are some of the most common stroke related sight loss conditions.  

 

Visual field loss

This is when parts of vision is lost. Hemianopia is when one half of vision is gone so those with the condition will only be able to see either the left or right half of what they are looking at. 

It is also possible to lose central vision, which may mean that it is not possible to directly look at something. 

 

Eye movement complications

Strokes can affect a victim’s control over their eyes. This may mean that the eyes are unable to coordinate with each other, which can cause diplopia (double vision). 

Some may also experience an uncontrollable wobble of the eyes (nystagmus) which can result in reading difficulties. 

 

Trouble with visual processing

Strokes can disrupt the way information is passed from the eyes to the brain and how that is processed. This miscommunication can often result in visual neglect, which is when something that is seen is not processed and therefore does not register with the individual. You may find that these individuals will unintentionally ignore people or objects because their brain has not interpreted the data sent by the eyes. 

The other extreme is also possible as many will experience hallucinations caused by processing errors by the brain, giving them images of things that aren’t actually there. 

 

Due to the wide range of visual conditions suffered by stroke victims, there is no one-fix-for-all. Treatment can help the victim cope and adapt to their vision loss, and can come in the form of rehabilitation, accessories, or smart glasses, depending on the exact nature of their condition. 

Some people will find that their vision improves for up to 6 months after their stroke. But again this depends on how well their brain heals after the initial damage. 

stephen hicks oxsight cofounder

OXSIGHT Co-founder Stephen Hicks on the HealthRedesigned podcast

oxsight on healthredisned podcast

 

OXSIGHT co-founder and head of innovation Stephen Hicks was invited onto the HealthRedesigned podcast to talk to Matt from Hanno.

They discuss neuroscience, delve into augmented reality, and how OXSIGHT is helping those with vision problems.

This is a rare insight in the more technical side of OXSIGHT and what we are working on and the challenges that need to overcome to help as many people as possible.

Listen below and enjoy!

 

 

Primer on Glaucoma

Glaucoma can trace its roots to Ancient Greece and is derived from the word Glaux which means owl. Ancient Greeks had a propensity to name diseases after animal due to their belief that this animal would then help the patient combat the disease. 

And so it is the owl that plays a central role in combating Glaucoma. 

Ancient Greek gem showing an owl taking centre stage in the fight against eye disease

Ancient Greek gem showing an owl taking centre stage in the fight against eye disease. [lww.com]

Glaucoma is an eye condition where the optic nerve is damaged. This is normally caused through buildup of fluid in the eye which increases pressure. The pressure can injure or exploit a pre-existing weakness in the optic nerve. 

The effects of this damage may not be noticeable at first due to it normally developing over many years and primarily affecting peripheral vision. Because of this it is advised to take regular eye tests as this is usually how glaucoma is detected. 

Due to the variable nature of the cause, there are five main types of glaucoma, with most characterised by patchy blind spots in peripheral or central vision of both eyes. 

  • Primary open angle glaucoma is the most common type and is characterised by slow damage to the optic and changes to eyesight. 
  • Closed angle glaucoma occurs when eye pressure rises suddenly and can be very painful.
  • Normal tension glaucoma is when the pressure is within the normal range but damage to the optic nerve still happens. 
  • Secondary glaucoma is a result of the presence of another eye condition, an injury to the eye, or certain medication or treatments. 
  • It is also possible to be born with an improper drainage system in the eye causing congenital glaucoma.

Currently, there is no cure to restore the vision of someone with glaucoma. However, it is possible to stop or slow the degradation of vision and stave away permanent sight loss by controlling the level of pressure in the eyes. 

Eyedrops are the most common form of treatment with many people using them daily for many years. For some, it may be necessary to have laser eye treatment or surgery to help control the pressure. 

Recent developments have seen specialty glasses produced which can condense a wider field of view and display it in a patient’s more narrow field of view, effectively replacing part of their lost vision. More and more people are finding these smart glasses useful in their daily lives and the future points towards more advanced developments and further innovation in this field.