We conducted complete eye examinations and retinal function tests on nine patients who had undergone jejunoileal bypass (JIB) surgery and subsequently had low serum vitamin A levels. All patients had manifested clinically demonstrable keratoconjunctival xerosis; in addition, two had abnormally high dark-adaptation final thresholds, and two had concomitant implicit prolongation in the electroretinogram. The age-matched control groups that consisted of 14 patients with various gastrointestinal disorders and four asymptomatic volunteers showed fewer or no ocular abnormalities. Our findings suggest that, even though patients who underwent JIB surgery may manifest keratoconjunctival xerosis and have low serum vitamin A levels for several months to years, retinal function will remain normal until the tissue stores of vitamin A are depleted. A long-term ophthalmologic follow-up of JIB patients, therefore, is recommended.