Melatonin levels in patients with primary open angle glaucoma with high or low intraocular pressure

초록

Purpose: To evaluate circulatory melatonin levels by assessing nocturnal urinary excretion of 6-sulfatoxymelatonin (aMT6s) in patients with primary open angle glaucoma (POAG) and to compare the high-tension group and the low-tension group. Methods: This study included 41 POAG patients and 44 control subjects. POAG group was further classified into high-tension group and low-tension group according to the pretreatment intraocular pressure. The first urine in the morning was collected and aMT6s were measured using a commercial ELISA kit. Urinary aMT6s levels were expressed as ng aMT6s/mg creatinine. Differences in melatonin levels among the control and POAG subgroups were evaluated by generalized estimating equation adjusting age, sex, sleep duration, and inter-eye correlation. Results: Urinary aMT6s/creatinine ratio did not differ between POAG and control group (P = 0.097). The difference in the aMT6s/creatinine ratio between the three groups? high-tension group with baseline intraocular pressure (IOP) ≥ 21 mmHg (19.74 ± 14.44 ng/mg), low-tension glaucoma group with baseline IOP < 21 mmHg (26.71 ± 16.91 ng/mg), and control group (30.35 ± 30.51 ng/mg)?was statistically significant (p = 0.046). Post hoc analysis revealed that the difference between the control and high-tension glaucoma groups was significant (p = 0.014), while the difference between the control and low-tension glaucoma groups was not (p = 0.436). Conclusions: This study found low melatonin levels in high-tension glaucoma and high melatonin levels in low-tension glaucoma.