Patients at Great Ormond Street Hospital (Gosh) have become the first in the word to test a treatment that could prevent blindness in children living with CLN2 type Batten disease.

The rare degenerative genetic disorder affects 30-50 children in the UK and causes seizures then a gradual decline in the child’s ability to walk, speak and see, as well as progressive dementia.

Children have been treated with a drug called Brineura, which was administered directly to the brain and restored enzyme activity, but did not prevent blindness.

Researchers have now used a leftover amount of the drug from the brain infusion and injected it directly into the back of the eye to provide the required enzymes in the back of the eye.

Professor Paul Gissen, honorary consultant in paediatric metabolic diseases at Gosh and the UCL GOS Institute of Child Health, said: ‘If successful, we hope our work on this programme can pave the way to saving the sight of more children with this disease to preserve their quality of life for as long as possible.’

The eye injection has been given to a small number of patients who have been chosen by clinical teams with one eye treated every two months and plans to compare vision to the non-treated eye after a year.