Researchers in France say that the distorting spectacles can help stroke patients with posture problems to recover their balance. They think that the spectacles reset the patient's mental makeup and hope that the effect will lead to a long-lasting cure for some postural problems.
People who have a stroke affecting the brain's right hemisphere may suffer paralysis down their left side and can lean to the right. Caroline Tilkete and her colleagues at the Lyon neurological laboratory of INSERM the French medical research agency, gave wedge shaped spectacles with prismatic lenses to patients with postural problems. These made objects appear 10 degrees farther to the right or the left than they were.
As expected, when the patients were asked to point to objects they pointed too far to the left or right, depending on the lens. But when they took the spectacles off, the researchers found that patients who had been wearing the right-shifting lenses had lost their postural imbalance which lasted for several minutes.