Purpose:To investigate whether patients with primary open-angle glaucoma combined with high myopia (POAG-HM) have short-term intraocular pressure (IOP) fluctuations at resting conditions over 24 hours and after dynamic exercise.Methods:Prospective Control Clinical Study. Eighty eyes of 80 high-tension Chinese POAG patients only on prostaglandin analog locally were categorized as per their degree of myopia (myopes 6 D or more, n=30 and between -0.76 and -5.99 D, n=29) or without myopia (n=21). Twenty-four-hour IOP fluctuations at resting conditions were observed in protocol 1, and IOP fluctuations after 10-minute exercise at 20% maximum Watt (Wmax) and followed by 5 minutes of exercise at 60% Wmax were observed in protocol 2.Results:Twenty-four-hour IOP fluctuations at resting conditions were not statistically significant among groups (P=0.58). After 10 minutes of moderate (20% Wmax) exercise, patients with POAG-HM had significant IOP decrease (3.502.76 mm Hg) over other subjects (analysis of covariance, age, as a covariate, was controlled, P=0.02). After 5 minutes of heavy (60% Wmax) exercise, patients with POAG-HM had significantly a greater postexercise IOP decrease (7.57 +/- 3.47 mm Hg) than other groups (P=0.00).Conclusions:High-tension POAG patients with high myopia on only pharmacological glaucoma therapy have significantly greater IOP fluctuations after moderate and heavy exercise and do not have greater 24-hour IOP fluctuations at resting conditions.