Disclosed herein are various embodiments of a medical instrument used for conducting eye, ear, mouth examinations of a patient. The instrument is connectable with a remote power supply. In an exemplified embodiment, instrument comprises an elongated, rigid body defining a first end and a second end, a light emitting member disposed at the first end, and an input/output connector disposed at the second end and adapted for selective connection with the remote power supply, so as to enable operation of the light emitting member free of connection with the remote power supply. The instrument may also be used for sensitivity testing of skin areas of the patent.