A research group led by Assistant Professor Yasuhiro Shinmei and Professor Shin Ishida of the Graduate School of Medicine, Hokkaido University has succeeded in measuring intraocular pressure fluctuations at night, which was previously considered difficult in patients with sleep apnea syndrome, and also developed glaucoma. Announced the relationship with.The result was published in the American scientific journal "Investigative Ophthalmology & Visual Science".
"Sleep apnea syndrome" is a condition in which breathing stops repeatedly during sleep, and the estimated number of patients is 200 million, and there is a high risk of cardiovascular diseases such as cerebral infarction.In addition, it is known that the rate of glaucoma is about 10 times higher than that of normal people.
"Glaucoma" is a disease in which the optic nerve is damaged due to an increase in intraocular pressure and the visual field is narrowed.Since the incidence of sleep apnea syndrome is high, there is a view that intraocular pressure may increase due to apnea and cause glaucoma, but a clear causal relationship has not been clarified.Furthermore, although it is known that the intraocular pressure fluctuates depending on the time zone and posture, it was difficult to actually continuously measure the intraocular pressure during sleep.
In this study, a contact lens tonometer developed by a Swiss company was used to record intraocular pressure for 5 seconds every 30 minutes.At the same time, the state of sleep was monitored by recording brain waves, respiration, and electrocardiogram during sleep.Based on these results, we compared the intraocular pressures when breathing was stopped and when it was not stopped during sleep, and investigated the effect on apneic attacks.
As a result, it was found that the intraocular pressure normally rises when breathing is held, but when an aspiratory attack occurs, the airway obstruction prevents inhalation and lowers the intraocular pressure in the thoracic cavity, which is lower than when there is no attack. ..The high onset of glaucoma in sleep apnea syndrome is not due to an increase in intraocular pressure, but rather to a decrease in intraocular pressure and a decrease in oxygen saturation in the blood, resulting in hypoxia in the brain. The research group points out that it may cause disability.
This result shows that even if the intraocular pressure does not rise, the optic nerve may be damaged due to hypoxic conditions, which leads to the elucidation of normal-tension glaucoma, which is said to be common in Japanese people. It is expected.
