Blindness and visual impairment come in many forms. Not all people with impaired sight would benefit from our augmented vision, but there are many who would. As a general guide, if someone retains the ability to detect some light - as 75% of those registered blind do - it's possible these glasses can help.
There are several common and not-so-common conditions that cause vision to fail in this way. We have been considering the cases of Retinitis Pigmentosa, Diabetic Retinopathy, Age-related Macular Degeneration, and Cataracts.
This is a genetic disorder that comes in several different forms. It affects about one in every 4,000 people. It happens when the chemicals at the back of the eye stop reacting to light hitting them. This does not happen all at once - normally vision starts to become worse in poor light, and then to disappear around the edges of the field of vision. The ability to see continues to drop throughout the life of the patient, and there is no known cure.
Click here for more information about Retinis Pigmentosa.
If diabetes is not managed well, there is an 80% chance that damage to the eye will occur. Diabetes causes the body not to process sugars correctly, and so they can collect in the wrong places and damage blood vessels. This can also mean that the blood vessel that do grow are weak and in the wrong place. The blood vessels and the blood within them stop light getting to the sensitive cells at the back of the eye. Diabetic retinopathy can be treated by using lasers to get rid of the blood which is in the way, but this only stops the loss of vision. It does not restore it.
Age-related Macular Degeneration
The macula is the centre and most sensitive part of the retina. It is about the size of a pinhead, but takes care of a lot of your sight, picking out colours and fine detail. Age-related macular degeneration results from the light-sensitive cones in that part of the eye stopping working, but it is not known exactly why this happens. People with AMD lose the ability to see colour or detail in the middle of their vision, although the sight around the edges usually remains. Around 10% of patients between 66 and 74 years of age will have some macular degeneration. This goes up to 30% in patients who are between 75 and 85.
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A cataract is a clouding of the lens of the eye, caused when the proteins within the lens start to cling together. The lens is responsible for the eye's focus, and if it is not clear, the image that you see will not be clear either. In more economically developed countries, cataracts are easily treated by surgical removal and replacement with a plastic alternative. However, if the cataract remains, it will spread, thicken and become more and more opaque until blindness results.
Where can I get a pair?
The assisted vision glasses are not yet commercially available. We are busy building and testing prototypes with funds from the NIHR i4i program. The glasses are being put into validation trials with sight-impaired individuals to test how well they work with different types of visual impairements.
We hope to go into production with our first commercial version at the end of 2014.