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Search for Genes Causing Eye Disease


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retina cons and rods

retina cons and rods

Genes and Vision loss.  The retina is a thin, light-sensitive tissue at the back of the eye. It captures light and converts it into a chemical signal which travels to the brain, ultimately registering as vision. The retina is actually part of the central nervous system and is considered part of the brain. The ‘photoreceptors’ or light-sensitive nerve cells of the retina, are divided into the rod cells and the cone cells, reflecting their actual shapes.

There are about 120 million rod cells spread throughout the retina. These are responsible for black and white vision, and allow vision in low-light conditions. Then the six million cone cells are located in the centre of the retina, in an area called the macula, and are responsible for colour vision and detailed central vision.

A group of diseases collectively called inherited retinal degenerative disorders are caused by genetic defects which cause vision loss. This may result in total blindness. These disorders are caused by genetic changes or mutations and are inherited within families.

These genetic mutations result in different disorders. Gene defects affecting mainly the rod photoreceptors cause retinitis pigmentosa. As a result patients experience night blindness and loss of peripheral vision, causing a tunnel-like vision. Genetic mutations causing a primary loss of cone photoreceptors result in Stargardt disease or macular degeneration and cause a loss of central vision.


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