Development of a Flexible Electrode for Electrical Stimulation of Rabbit Extraocular Muscle.

Background/objective: To develop a flexible electrode for electrical stimulation of extraocular muscle and to evaluate the safety of applying direct electrical stimulation to muscle and its potential effects on ocular tissue in rabbits.

Methods: A flexible electrode was fabricated using a conventional photolithography process. This electrode comprised a 300nm-thick platinum layer embedded within a 30μm-thick polyimide cable. In an in vivo study, five rabbits underwent electrical stimulation of the right superior and inferior rectus muscles. Stimulation consisted of 12 pulses (1 pulse/second, 2.0 mA, 0.1 ms duration) applied for five minutes to the right superior rectus muscle, followed by five minutes to the right inferior rectus muscle. This regimen was performed three times a week for four weeks. Subsequent histological examination was conducted on the conjunctiva, extraocular muscles, sclera, and retina.

Results: Direct electrical stimulation of extraocular muscle using a flexible electrode could successfully elicit eye movement in rabbits. Histologic examination demonstrated no evidence of detrimental effects of the electrical stimulation.

Conclusions: Direct electrical stimulation of extraocular muscle using a flexible electrode could safely elicit eye movement without any ocular damage in rabbits.