Patients who suffered from partial blindness after a stroke regained sight after undergoing Visual training designed by researchers at the University of Rochester Medical Center’s Flaum Eye institute.
A new study in Neurology, the medical journal of the American Academy of Neurology gives first evidence that vision could be revived back in patients who suffered primary visual cortex damage through rigorous visual training. Damage to visual cortex prevents visual data from being transmitted to other areas of the brain that help sensing it causing loss of sight in an individual’s normal field of view. Around 250,000 to 500,000 people suffer vision loss due to visual cortex damage every year.
Most clinicians still think nothing could be done to reverse this visual loss due to primary visual cortex. It is widely believed that vision loss stabilizes 6 months after stroke. Patients with visual cortex damage no longer given the hope of recovery.
Visual therapy:
Hulix, Professor in the department of Neuroscience, Brain & cognitive sciences and the center for visual science at UR, developed a kind of physical therapy for the visual system- a means of rerouting visual information around the dead areas of the primary visual cortex.
Her team created personalized software programs for 17 cortically blind patients that flashed small circles of striped patterns or moving dots in the patient’s blind field, in the areas where they could no longer see. Patients reported the orientation of the stripes or the direction.
Initially patients only made guesses half of the time, however over the time they began sensing and could gradually see enough of the patterns and dots to answer correctly 80% of the time. Clinical tests also revealed that patient’s blind fields shrank and gaining vision back were hard for them to describe.
1 patient said she no longer had difficulties in seeing post stroke- like the time she missed the “W-o” on the women’s room signboard and wondered why 2 men’s restrooms would be side by side. Faces and objects that looked squat and distorted after stroke also returned to normalcy. Several patients could get back to driving after undergoing Hulix’s visual training and a driver rehabilitation program.
Patient’s change from nothing to a sensation of motion, to vision, albeit not quite normal vision. This study also challenged conventional knowledge that cortically blind patient’s visual deficits stabilize 6 months post stroke. In the study, patients with visual deficits who did not undergo any visual training continued to worsen. The research team is verifying this finding in a bigger group of cortically blind patients by studying how blind field maps change over time after stroke. These results could be implemented for training patients who would benefit from early intervention.
Any patient regardless of age, blind field size, or duration post stroke could have meaningful improvements in sight in around 3 months when trained twice a day for 30 minutes each time. However, patients should continue training as long as they see improvements.
Huxlin’s visual training technology has been licensed by EnVision LLC, which will sponsor a clinical trial to be conducted at several sites including the URMC Flaum Eye Institute. Huxlin and the University of Rochester may benefit from royalties should the technology be commercially successful.