• Vani A
• Vrinda Marigowda
• Arun Sasidharan
• Chetan S Mukundan
• Dr. Mamatha MN, Sumit Sharma

Background:Visual system of brain computes the visual details to detect and interpret information in the visible light. This is a complex process that includes reception of light, binocular perception, estimation of distance and categorization of objects. An anomaly in any such process causes blindness or visual Impairment. Most of the blind-aid systems use audio feedback, but this could interfere with one’s attention to other environmental auditory cues. Moreover, a non-invasively delivered visual feedback for visual stimuli would be more intuitive and appealing than an auditory feedback. Hypothesis:tACS non-invasively provides very low electrical simulation (in micro amperes) to the posterior part of brain, which is perceived by the subject as ‘flashes of light’. By altering electrical characteristics of the stimulation (such as current and frequency), we hoped a change in the perceived flash rate, which can then be used as the different levels of visual feedback. Methods:As a proof to this concept, the current work tested a novel approach where different levels of visual feedback was provided using transcranial alternating current stimulation (tACS) to nine blind folded individuals(males=9; age = 20-35yrs) (mimicking visual impairment). In this study, we used three stimulation parameters for slow, medium and fast flash rates and presented them in random sequence and repetition. Results:Though the current threshold differed between individuals, all participants correctly reported the change in flash rate corresponding to the stimulation frequency. Conclusion:tACS stimulations that cause perception of flashes could be a viable approach for the development of a wearable visual-feedback blind-aid system.

transcranial Alternating Current Stimulation (tACS), non-invasive visual feedback, blind-aid system

"Visual feedback system for visually impaired using tACS – a proof of concept study", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 1, page no.738-743, January-2019, Available :http://www.jetir.org/papers/JETIR1901595.pdf

"Visual feedback system for visually impaired using tACS – a proof of concept study", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 1, page no. pp738-743, January-2019, Available at : http://www.jetir.org/papers/JETIR1901595.pdf