The Impact of Sight Loss

96% of people who are registered blind/severely sight impaired have some useful, residual vision. Only 4% see nothing at all. Particular Eye Conditions affect vision in different ways. Thus, visually impaired people adopt a range of strategies to make best use of their remaining vision.

The six most common eye conditions in the UK are Cataract, Glaucoma, hemianopia, Retinitis Pigmentosa, Age Related Macular Degeneration, and Diabetic Retinopathy

 

Retinitis Pigmentosa

This is a common umbrella term for a lot of sight conditions and could affect your vision in dim light or in the dark and it could also mean loss of your peripheral vision.

Glaucoma

Optic nerve damage stops messages being sent to brain from the eye causing pressure which distorts vision. Misty vision is sometimes a consequence of Glaucoma and can affect people in very different ways.

Cataracts

A very common condition in older people that affects the lens of the eye making vision foggy or misty

Diabetic Sight Loss

When sight is lost through damage to the blood vessels or poor diet can affect the health of the eye causing shimmering and blood in the eye.

Macular Degeneration

Sometimes the delicate cells of the macula become damaged and stop working and there are many different conditions which can cause this.   If it occurs later in life it is called Age Related Macular degeneration (AMD). There are two types of macular degeneration usually referred to  as wet and dry. Dry AMD is the most common form of the condition. It develops very slowly and causes gradual loss of central vision  and there is no medical treatment for this type.

Wet AMD results in new blood vessels growing behind the retina causing bleeding and scarring which can lead to sight loss.  Wet AMD develops quickly but responds to treatment if caught in the early stages. It accounts for about 10 percent of all people with AMD. Both wet and dry AMD usually affect both eyes but one may be affected long before the other; this sometimes makes it difficult to notice at first because the sight in the good eye compensates.

Homonomous Hemianopia

Visual problems are more common in people who have suffered a stroke affecting the right side of their brain.  The damage caused by the stroke impacts on the visual pathways which can result in visual field loss.  When the stroke affects the area of the brain that processes information it can cause visual neglect, lack of awareness to one side of the body and space, as well as difficulty judging depth and movement. Strokes can cause whole sections of the visual field to be missing. Hemianopia is the loss of one half of the visual field, affecting both eyes.

These six conditions virtually cover all aspects of sight loss. These include loss of central vision, loss of peripheral vision , loss of half vision and distorted full vision.

Loss of central vision is associated with  AMD and sometimes RP. This means a person is no longer able to see print, facial expressions, or patterns and colour and facial recognition becomes difficult. However, some people are able to use their peripheral vision by not looking directly at the object or person they are trying to see. In this way, they can watch TV, or look at someone when they are in conversation.

Loss of peripheral vision is associated with RP and Glaucoma. It causes loss of spacial awareness, for instance movement not directly in front of the person, inability to judge depth, difficult to see in the dark and difficult to walk in a straight line. It is sometimes referred to as ‘tunnel vision’. However, many people can see something, such as print, or a face, if it is directly in front of them. Print may have to be enlarged to be accessible. People who have lost their peripheral vision can often be misunderstood. They may be seen reading print on a bus or train and then asking for help to cross a road when they disembark.

Distorted vision occurs with cataract, diabetic retinopathy Hemianopia and RP. Vision can be very blurred and shimmer so the picture is constantly moving. Patches causing lots of blind spots, like looking through a heavy net curtain. Double vision either horizontally or vertically, can occur in people with RP and Hemianopia.

Seeing only half of the picture with either right or left half of the field missing is associated with Hemianopia. It is like looking at a plate of food in front of you and only being aware of half of it. Simple strategies like turning a plate around during a meal can overcome this problem.

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For further information about eye conditions, please visit RNIB