Human tear glucose.

By means of a photometric method, the glucose concentrations of 875 human tear samples were analyzed. The arithmetic mean for the total population was 7.5 mg/dl, although significant differences in average concentration among individuals were found (3.4 to 12.7 mg/dl). Although the total population mode, 3.2 mg/dl, did fall within range limits often cited in the current literature, the higher arithmetic mean found here is attributed to special precautions taken to minimize reflex tear inclusion, to corrections made for effects of processing delay, and to the assembly of more extensive and time-balanced sample bases (an average of 73 specimens taken hourly throughout the waking periods of 5 days) for each individual studied. The population diurnal profile (i.e., the average of 60 individual profile days constructed here) was found to have some phase characteristics resembling those of serum glucose population profiles in the literature.