AN MD11 CAPT ON AN OVERWATER FLT SLEWED THE ALTIMETER ADJUSTMENT KNOB WHEN TRYING TO ADJUST LIGHTING; CAUSING A MOMENTARY ALT EXCURSION.

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FLYING FL330; IN CRUISE WITH AUTOPLT 1; I REACHED UP TO ADJUST THE GLARE SHIELD PANEL FLOODLIGHTS. THIS KNOB IS ADJACENT TO AND SIMILAR IN SHAPE TO THE ALTIMETER ADJUSTMENT KNOB. I MISTAKENLY ROTATED THE ALTIMETER ADJUSTMENT KNOB; AND SUBSEQUENTLY HEARD THE ALT TONE AND VOICE. UPON HEARING THAT; I INSTINCTIVELY CLICKED OFF THE AUTOPLT AND CHASED THE ALT; MANUALLY CORRECTING TO THE ASSIGNED ALT. THE AIRPLANE; OBVIOUSLY; HADN'T MOVED; BUT I CORRECTED TO A BARO SETTING OF 1026; WHICH GAVE US A 700 FT ALT ERROR. I IMMEDIATELY CAUGHT ON TO THAT; AND SUBSEQUENTLY PULLED THE ALTIMETER KNOB; RESETTING THE STANDARD ALTIMETER AND I WAS THEN ABLE TO CORRECT TO THE PROPER ALT. AFTER I WAS BACK ON ALT; I TOLD NAHA ATC EXACTLY WHAT HAPPENED; AND THERE WAS NO OTHER TFC IN THE AREA. CONTRIBUTING FACTORS TO THIS ERROR WERE AS FOLLOWS: SOME ELEMENT OF FATIGUE; AND THE DESIGN OF THE PANEL; NEITHER OF WHICH ARE ISSUES THAT CAN BE ADDRESSED. WE'LL LEARN FROM THE MISTAKE AND MOVE ON. THIS FLT IS A LATE DEP OUT OF HONG KONG; AND I WAS NOT ABLE TO GET A LOT OF REST IN THE HOTEL DUE TO A NOISY NEIGHBOR. TO ADD TO THAT; CREW SCHEDULING INTERRUPTED THE LITTLE SLEEP I DID GET WITH SOME UNRELATED REQUEST.