A fiber-optic intensity sensor has been developed for vertically positioning microelectrode arrays above the retina of a live frog. Closely spaced fibers illuminate and collect reflections from the retinal surface, and the output is electronically processed to drive an automated positioning circuit. Experimental and theoretical evaluations of fiber types and separation for both specular and diffuse reflectors, <i>in vitro</i> and <i>in vivo</i>, are presented, and multimode fibers on 125-μm centers are chosen for retinal experimentation. The sensor has applications in assessing spatial selectivity of stimulation of a multielectrode array and may be adaptable for lateral positioning.
© 1998 Optical Society of America
(000.1430) General : Biology and medicine
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(170.3890) Medical optics and biotechnology : Medical optics instrumentation
Peter G. LoPresti and Warren E. Finn, "Fiber-Optic Sensor System for Rapid Positioning of a Microelectrode Array," Appl. Opt. 37, 3426-3431 (1998)