Abstract
Abstract: :
Purpose: To evaluate the effect of trabeculectomy on circadian variations of intraocular pressure (IOP). Methods: Nineteen eyes of 12 patients with normal tension glaucoma and primary open angle glaucoma, whose visual field had been deteriorated, underwent trabeculectomy. IOP was measured every 3 hours over a 24–hours of period, pre–operatively under glaucoma medications within 1 month before operation, and post–operatively under no medication more than 3 months after operation. Mean of 24–hour IOP, maximum IOP, minimum IOP, range of IOP fluctuations, and the time of peak and trough IOP were compared between pre– and post–operative measurements. Results:Mean 24–hour IOP, maximum IOP, and minimum IOP before trabeculectomy (mean +/– standard deviation: 15.6 +/– 2.4 mm Hg, 19.3 +/– 3.0 mmHg, 12.2 +/– 2.5 mmHg, respectively) decreased after trabeculectomy (10.0 +/– 3.3 mmHg, 12.0 +/– 4.2 mmHg, 8.1 +/– 3.0 mmHg, respectively). All changes were statistically significant (p<0.0001). The range of IOP fluctuations also reduced significantly after trabeculectomy (7.1 +/– 2.3 mmHg to 3.9 +/– 2.4 mmHg; p<0.0001), and post–operatively the range became less than 2 mmHg IOP in 7 eyes (36.8%). In 4 eyes (21.1%), the peak time stayed unchanged post–operatively, and the time changed in the rest of the eyes (within 3 hours: 4 eyes, 3 to 6 hours: 3 eyes, 6 to 9 hours: 5 eyes, 9 to 12 hours: 3 eyes). Conclusions:It is still unclear which is the more important causative factor for glaucomatous optic nerve damage, maximum IOP or fluctuation of IOP. However, trabeculectomy not only reduce IOP but also flatten circadian IOP.
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • intraocular pressure • circadian rhythms