Irish researchers have developed a groundbreaking technique which could in the future be used to treat one of the world's most common forms of hereditary blindness.

Retinitis pigmentosa (RP) is the name given to a group of hereditary eye disorders, which affect the retina. The retina is the light-sensitive tissue lining the back of the eye, in which the first stages of seeing take place. In RP, sight loss is gradual but progressive.

In Ireland, up to 80,000 people are affected by degenerative retinal conditions.

Details of the new technique were presented at an international conference, Retina 2010, in Dublin. Over 80 Irish and international delegates attended the event, which was hosted by Irish charity, Fighting Blindness.

Among the speakers was Dr. Anna-Sophia Kiang of Prof Peter Humphries' laboratory at the Smurfit Institute of Genetics in Trinity College Dublin (TCD). The team there has developed a groundbreaking method of delivering therapeutic drugs more easily into the retina at the back of the eye.

They have proven experimentally that one drug in particular, which is already being used for other conditions, is extremely potent in preventing a form of RP when administered in conjunction with this latest technology.

If approved for clinical use in humans, this could offer new treatment options to those affected by degenerative eye conditions.

"Many cases of RP could be treatable using drugs but the problem has been that getting therapeutics into the human eye is not easy. Blood vessels that supply the retina are lined by tightly-packed cells that create a barrier, called the inner blood-retina barrier. So ordinarily, if a drug is administered in tablet form, the barrier would prevent it moving from your blood to the retina," explained Dr Kiang.

The blood-retina barrier exists to protect the delicate tissues of the retina from dangerous pathogens and foreign molecules. However, it also acts as a barrier to the entry of therapeutic agents. The team at TCD has developed a new approach that uses specifically designed RNA to suppress production of a protein called claudin-5, a key component that stops drugs moving across from the bloodstream.

"We have come up with a highly controllable system to reversibly loosen the tight seams just enough to let small molecules pass through and in principle, this will offer clinical options to treat degenerative eye conditions such as RP with systemically administered drugs," Dr Kiang added.

Welcoming the findings, Fighting Blindness chief executive, Avril Daly, noted that Ireland has ‘reaffirmed its position as a global leader in vision research today'.

"This study is testament to the significant progress being made by Irish researchers on the world stage," Ms Daly said.

The conference took place in Dublin City's Radisson Royal Blu Hotel.

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