Touching Lives - June 2003
Blindness in later life -- understanding why it happens
Dr Paul Goldsmith, Specialist Registrar in Neurology based at Cambridge University, has completed a three-year project funded by Action Medical Research studying the mechanisms behind the degeneration of the retina.
If you imagine the eye as a camera, complete with a lens, then the retina at the back of the eye would be the film. It registers shades and colours thanks to the arrangement of special cells known as rods and cones — and it’s the degeneration of those cells that causes the breakdown in vision that severely affects the quality of life for those afflicted.
Dr Goldsmith’s project has identified factors that influence the survival or degeneration of the cells in the retina and he hopes that as a result of his work, drugs will be developed to prevent the death of the cells in the eye by mimicking the properties of those that survive.
One in 20
He told us: “One in 20 people will suffer degenerative blindness in later life. The condition is actually on the increase because we have an ageing population in the UK, so it’s vital that we do all we can to understand the problem and try to prevent it.
“There are currently no treatments for the underlying cause of degeneration of the retina. Surgery can correct problems at the front end of the eye such as cataracts, but there is little that can be done to prevent this age-related damage at the back of the eye.”
Dr Goldsmith has discovered that in terms of cell degeneration, there is not just one underlying condition but several, and he has found that a fundamental mechanism underpins them all.
He said: “That’s really important. ^If we can find a common root cause it means that we can develop a drug to treat all the underlying conditions^ which together make up what is currently referred to as macular degeneration, not just therapy that might only benefit a few hundred people.
“We have found that in people with degeneration of the retina, when one cell in the retina dies, it also kills off the cells around it, and gradually this causes blurred vision and ultimately blindness.
“This interdependency of cells is the key. We need a drug that can mimic the properties of the cells that survive, so the death of one cell doesn’t mean the death of a neighbouring cell.”
Dr Goldsmith added: “The implications are enormous. The back of the eye is the only part of the central nervous system that the doctor or researcher can actually see — that’s why we say it is a ‘window on the brain’ and why doctors are often keen to look into the eye to help the diagnosis of a range of conditions.
“Understanding this type of cell degeneration could have significance for the treatments of neuro-degenerative diseases such as Alzheimer’s, Parkinson’s or Huntington’s, because the cells of the retina are the same as those of the cortex and central nervous system. It’s fascinating and very rewarding work.”