How eye conditions can affect your sight
Different eye conditions can affect our vision in particular ways.
At Blind Veterans UK, we find it more useful to focus on the effects of someone’s eye condition rather than on the condition itself.
This is because it helps us to understand the specific challenges of their vision impairment and how best to support them.
The three aspects of sight loss
When your vision is impaired, what you can see will depend on the part of the eye or vision processing affected. There are three key aspects to this:
- Firstly, the centre of your vision is where the detail, colour and bright light vision is.
- Secondly, your peripheral vision is where your movement sensitivity and low light vision is.
- And, thirdly, we actually see with our brain, so your eyes are like cameras feeding back information that your brain converts to an image.
Below, we summarise how an impairment in any of these areas can affect your vision:
Central sight loss
If you have a central sight loss, typically the result of macular degeneration, you’re likely to have a reduced central field. This impairs your ability to see details and colour, while very bright conditions can be uncomfortable or even detrimental.
Central sight loss can often start with a single small spot in the centre of your vision that enlarges over time, or your central vision may appear distorted or opaque.
Hopefully, you will be able to use your peripheral vision to compensate to some extent, which although lacks detail will enable you to see a little.
Peripheral sight loss
If you’ve lost your peripheral sight, the outer edges of your sight may become blurry or opaque.
Although you may still be able to see detail, your sight is likely to be dependent on good lighting and reduced field of view, otherwise known as tunnel vision.
Your colour vision may not be affected, but the restricted view and need for good lighting may cause issues around mobility, particularly in low light conditions.
Blind spots and distorted vision
The field of view can also be affected by an obstruction to the path of light to the retina at the back of the eye. This can cause blind spots which can move around, or general blurred vision or visual distortions.
This can happen with eye conditions such as diabetic retinopathy which causes small bleeds into the eye that can move around and often come and go.
Also, cataracts can cause a general blurring and reduction in clarity of vision, often described as looking through a dirty window.
As your brain controls your sight, there are many ways in which your vision can be affected by a neurological cause. Conditions that affect the brain, such as strokes and brain trauma, can cause changes to your vision depending on how your brain or the nerves are affected.
Any eye condition or field loss can be complicated by Charles Bonnet Syndrome, whereby you see things that aren’t there. This is a very common condition for anyone with sight loss as the brain tries to make sense of the limited information it receives from the eyes.