Reversible night blindness associated with intestinal bypass surgery.

A 33-year-old man had a sudden onset of night blindness 3 1/2 years after intestinal bypass surgery for morbid obesity. Ocular examination disclosed a probable Bitot's spot and electrophysiologic testing showed markedly impaired dark adaptation and subnormal electroretinography. After therapy with orally administered vitamin A, the night blindness disappeared and the dark adaptation curve and electroretinogram returned to normal.