Optic nerve micro-stimulation
Bernhard A Sabel PhD
Visual field defects can be reversed by reactivating “silent” neurons using electronic micro-stimulation of the eyes and brain, Prof Bernhard A Sabel PhD told AAO 2020 Virtual.
Prof Sabel, of Otto-von-Guericke University, Magdeburg, Germany, described a device that delivers electrical pulses through pads at the temple and above the eyes. Stimulation travels through the eye and the optic nerved to the brain’s frontal cortex, 40 minutes per day for 10 days. In a clinical trial involving 623 patients, 84% experienced an increase in visual field size averaging 24%, with 60% better vision in the impaired visual sector. Response is highly variable with one patient’s visual field index improved from 19% to 63%. (Gail, Sabel et al. PLoS ONE 2016).
The improvement cannot be explained by the growth of new cells or rescuing cells from death, Prof Sabel said. Rather, it likely is due to reactivation of hypo-metabolic “silent” neurons, which survive the disease.
Evidence for this reactivation includes changes in brain function with increased messaging from the occipital cortex to the frontal cortex after stimulation, as well as increased brain oxygenation in these areas. Electronic stimulation increases the potential for neurons firing, releasing potassium that stimulates dilation of the blood vessels, increasing blood supply, Prof Sabel explained. This may help reactivate cells rendered dormant through vascular dysfunction.
This technique has the potential to reverse not only glaucoma, but also optic nerve damage and retinal trauma, diabetic neuropathy, vision loss after stroke or brain trauma, and macular degeneration, Dr Sabel said.