Blindness treatments to benefit from new in-'sight'

New research shows that the areas of the brain responsible for vision do not reorganise themselves when the eye is damaged by disease. This surprising finding, which opposes the prevailing world opinion in this area, is of great importance for developing treatments to overcome blindness. Researchers funded by the Medical Research Council from the University of York, University College London, Moorfields Eye Hospital and the University Medical Center Groningen/University of Groningen published their findings in the journal Nature Neuroscience on March 28, 2011. They report on an investigation of brain signals in patients with macular degeneration.

Macular degeneration stops the central, most important part of the retina (the light-detecting region at the back of the eye) from detecting light. This interferes with patients' abilities to recognise faces and to read, with one form of the disease the leading cause of registered blindness in Europe.

Until now it was thought that the areas of the brain responsible for processing visual information reorganised themselves when visual input is lost. This research provides compelling evidence that the brain is limited in the extent to which this takes place in patients with macular degeneration. This counters the contemporary view of brain's ability to reorganise itself. The results of the study are very important for people with macular degeneration. New cures for the disease, which are subject to intensive research worldwide, aim to restore function to the damaged regions of the retina. However, these approaches can only deliver maximum benefit to the patient if the brain remains correctly organised to process the restored retinal signals.

This work shows that there are no large-scale changes in the areas of the brain that receive information from the eye in macular degeneration patients. This means that no large scale brain changes would have to be 'undone' to allow new treatments for macular degeneration to work successfully.

Dr. Frans Cornelisse of the department of Ophthalmology of the University Medical Center Groningen said: "The results of the study are very important for people with macular degeneration. We found that the brain doesn't remap visual information in patients who lose part of their central vision. The approaches being taken to restore sight in patients with macular degeneration rely on the brain being able to process restored retinal signals. Our work is an important step in showing that the brain hasn't reorganised to limit the success of new approaches to curing this disease."

Researcher Koen Haak from the University Medical Center, Groningen, adds: "The results are not only important for visual rehabilitation. The visual impairment simulations and analyses that we have used in the present study open up numerous possibilities to investigate the human visual cortex with unprecedented detail."

Source: University of Groningen