The aim of this study is to evaluate the effects of fasting and dehydration on the efficacy of antiglaucomatos agents.

The study group consisted of 50 patients with regular IOP, 6 patients with no medications (Group 1), 11 with betablocker monotherapy (Group 2), 10 with prostaglandin analogue (PGA) monotherapy (Group 3), 12 with PGA in the combined therapy (Group 4), 11 without PGA in the combined therapy (Group 5). The average of the last three IOP measurements during non-fasting period were compared with the IOP values during fasting period between the groups and in the groups.

Mean IOP values of all patients increased during fasting period compared with baseline measurements. The most significant increase was in the third group with 2.90 mm Hg (p=0.007). The mean increase of IOP and p values in other groups were: Group 1: 1.83 mm Hg (p>0.05), Group 2: 1.54 mm Hg (p<0.05), Group 4: 2.83 mm Hg (p>0.05), Group 5: 0.81 mm Hg (p<0.05). When compared with the baseline values, IOP values during fasting period didn’t significantly differed between groups.

We conclude that values during the prolonged fasting and dehydration may due to the disregulation of IOP. Although this alteration might be explained by compliance deficiency, it must be kept in mind that, the mechanism of the drugs may be the reason.