[Dark adaptation of patients with head and neck tumors].

20 patients with tumors of the head and neck region have a delayed dark adaption. The serum vitamin A levels in these patients are significantly diminished versus controls. Since disturbance of dark adaption does not occur before long during deficiency of vitamin A, it is assumed that the deficiency was existent long time before. With regard to the possible antineoplastic potency of vitamin A, this is considered a possibly important factor in tumor development and growth. The disturbed vitamin A metabolism is possibly due to a long lasting imbalanced diet.