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Using the contact lens sensor in conjunction with polysomnography—equipment used to track multiple factors of sleep—researchers are able to measure both apnea events and IOP simultaneously. Researchers hope to demonstrate that during apnea events there is spike in IOP, as pressure in the chest rises when people stop exhaling. The results, however, are quite the opposite of what they anticipated: apnea episodes are associated with a drop in IOP.2
OSAS is still associated with glaucoma, but researchers have now realized that it isn’t due to an IOP increase or changes in chest pressure. Instead, it might be due to a drop in oxygen levels in the blood, which happens when you stop breathing. Routine low oxygen concentration in the blood may contribute to degradation of the optic nerve, potentially leading to glaucoma. As this appears to occur in apnea patients with glaucoma in the absence of a change in IOP, this revelation may provide insight into those with normal-tension glaucoma (NTG). This also could explain the correlation between OSAS, heart attacks and strokes: in all three cases, there is a prolonged period of oxygen deprivation.
The causes of normal-tension glaucoma remain unknown, but new theories are emerging. Much like primary open-angle glaucoma, without regular trips to the eye doctor to check the optic nerve for signs of damage, it may go unnoticed until significant vision loss has occurred. Earlier diagnosis and better understanding of this form of glaucoma may help preserve sight.
With novel discoveries and new technology to implement in studies of this disease, researchers may be able to uncover the underlying triggers of all varieties of glaucoma. The more that researchers understand about this challenging disease, the more likely they are to find a cure.
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1 “Efficacy of a Contact Lens Sensor for Monitoring 24-H Intraocular Pressure Related Patterns,” May 5, 2015, http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0125530
2 “Continuous Intraocular Pressure Monitoring During Nocturnal Sleep in Patients with Obstructive Sleep Apnea Syndrome,” May 2016, http://iovs.arvojournals.org/article.aspx?articleid=2525820#125975213
Last reviewed on October 29, 2017