I ran across a study published last year which tested a new kind of hearing aid that uses a light-based Behind The Ear (BTE) sound processor, and a removable, custom-made Tympanic Contact Actuator (TCA) placed by an ENT at the base of the ear canal. The BTE uses a microphone and a digital signal processor to pick up sound and convert it to infrared light. This non-visible light carries both the power and the sound signal to the TCA, which then converts it into imperceptible vibrations that are directly applied to the eardrum through a tiny custom contact pad and perceived as sound.
This device is not yet on the market. It is being developed by Earlens corporation, based in Silicon Valley. They have a website: http://www.earlenscorp.com/ The trial involved only a small group of 13 who got bilateral contact devices inserted next to the tympanic membranes in both ears. These recipients showed no problems with the device during a trial of only 113 days, but I think this is an exciting idea for us to watch. I hope it comes to market soon and will be useful for even those of us with severe to profound hearing loss.
Fay JP, Perkins R, Levy SC, Nilsson M, Puria S. (2013) Preliminary Evaluation of a Light-Based Contact Hearing Device for the Hearing Impaired. Otology & Neurotology 34:912-921.