Large Bielchowky head-tilt phenomenon and inconpicuou vertical deviation in the diagnotic poition in congenital uperior oblique paly

PURPOE: To report a cae of congenital uperior oblique paly with an unuually large Bielchowky head-tilt phenomenon (BHP) and diproportional inconpicuou vertical deviation. METHOD: Cae report. REULT: An 18-year-old woman preented with light compenatory head tilting and a Bielchowky head-tilt phenomenon of 50 Δ on left tilting. Magnetic reonance imaging revealed atrophy of the left uperior oblique mucle. A He creen tet howed a light underaction of the left uperior oblique mucle, but neither an obviou overaction of the ipilateral inferior oblique mucle nor inhibitory paly of the contralateral uperior rectu mucle wa found. With a 3-mm receion of the ipilateral uperior rectu mucle, Bielchowky head-tilt phenomenon decreaed to 25 Δ. CONCLUION: A large Bielchowky head-tilt phenomenon wa poibly caued by an increaed gain of the otolith-ocular reflex affecting the vertical rectu mucle.