A retinal prosthesis has been developed using liquid crystal polymer that is small, eye-conformal, and long-lasting. The liquid crystal polymer is biocompatible with a very low moisture absorption rate compared to other polymers. It can be thermoformed into non-planar shapes, allowing an eye-conformal dome shape to be created from multilayer films. This prosthesis was implanted in a rabbit eye where it remained stable for a year without issues. Electrical stimulation of the rabbit retina was achieved, verifying the feasibility of the liquid crystal polymer electrode array.

1. Mongolia-Korea Conference on Biomedical Applied Science and Engineering
Enabling Vision for the Blind at Low Cost: Liquid Crystal
Polymer-based Retinal Prosthesis
Sung June Kim, Ph.D.
Professor, Department of Electrical and Computer Engineering, College of Engineering,
Seoul National University, Seoul, KOREA
Email: kimsj@snu.ac.kr
A novel retinal prosthetic device which is small, eye-surface conformable and long-
term reliable has been developed using monolithic encapsulation and deformation of
Liquid Crystal Polymer (LCP). The LCP is a biocompatible material having extremely
low moisture absorption rate compared to other conventional polymer materials such
as silicone elastomer, polyimide or parylene. The LCP is expected to be strong
candidate for future implantable neuroprosthetics that can provide long-term
reliability of the implant as well as keeping the inherent advantages of being
polymeric in that it is thin, flexible, allows miniaturization and low cost batch
manufacturing process. The LCP can be thermally bonded together and can be
deformed into non-planar structure by a simple thermo-forming process so that a
monolithic fabrication with an eye-conformable structure is feasible. Exploiting these
properties, we have developed an all-LCP retinal prosthesis by integrating electrode
array, planar coil, circuitries onto a multilayered LCP films and then deforming it into
a dome-shape to fit the curved surface of eyeball. This device consists of an circular
package of 14 mm-diameter with 1.3 mm-maximum-thickness having the weight of
only 0.45 g, a mere 1/10 of the weight of equivalent titanium package. The fabricated
device was implanted into a rabbit eye by attaching the package on the temporal
quadrant of eyeball and inserting the electrode array into the supra-choroidal space of
retina. The implanted device was stable in the rabbit eye for a year without showing
inflammation, displacement or protrusion. The feasibility of LCP-based retinal
stimulating electrode array was verified in vivo where evoked cortical potential (EECP)
of rabbit was recorded while stimulating its retina by LCP-based electrode array.
Sung June Kim received the B.S. degree in electronics engineering from Seoul
National University (SNU), Seoul, Korea, in 1978, and the M.S. and Ph.D. degrees in
electrical engineering from Cornell University, Ithaca, NY, in 1981, and 1983,
respectively. From 1983 to 1989, he was a Member of Technical Staff with Bell
Laboratories, Murray Hill, NJ. In 1989, he joined SNU, where he is currently a Full
Professor in the School of Electrical Engineering. Since 2000, he has been the
Director of the Nanobioelectronics and System Research Center (NBS), SNU, which
is an ERC funded by the Korean Science and Engineering Foundation. His interest is
in implantable neural prostheses, especially reducing cost to benefit more disabled
people in the world who cannot afford the high price of currently available devices.