Individuals who have normal to moderate hearing loss in one ear and no usable hearing in the other ear might be helped by a “CROS” (contralateral routing of signal) or  “BiCROS” (bilateral routing of signal) hearing instrument. By using a transmitter unit with a microphone that is worn on the ear with no usable hearing, sounds are gathered and channeled to the better ear, which is outfitted with a hearing instrument with a receiver. This way, the CROS hearing system feeds the sound from the non-hearing side to the better ear. With a BiCROS system, sound is sent from the non-hearing ear to the other ear, which hears but also needs amplification to overcome a degree of hearing loss.

P.S. Both CROS and BiCROS systems enable users to hear sounds from the non-hearing sides of their heads that might otherwise  have gone unnoticed.