Zinc-deficiency-induced retinal dysfunction in Crohn's disease

A patient with Crohn's disease and low serum zinc concentrations is presented who had markedly abnormal dark adaptation. Oral zinc supplementation produced an improvement in dark adaptation, and discontinuation of zinc therapy was associated with a worsening of dark adaptation. Serum vitamin A levels were normal throughout this period. We suggest that impaired retinal function is another manifestation of zinc deficiency in Crohn's disease that may be improved with zinc supplementation.