Keya Chakrabarty, B. Optom.
Optometrist, LVPEI, Bhubaneshwar, India
Are you facing any problems while sleeping at night? Caution: It may be associated with Obstructive Sleep Apnea (OSA). It can be a serious, life-threatening disease that may lead to different ocular diseases such as Optic Neuropathy. Want to know what OSA is and its association with ocular physiology? Let us discuss it.
OSA is defined as partial or complete episodes of upper-airway blockage, which create disturbances during sleep at night and may be associated with several systemic diseases, such as Diabetes Mellitus (DM), Hypertension (HTN), cardiovascular diseases, and migraine, among others. Excessive snoring, gasping for air, daytime drowsiness, frequent episodes of apnea, mood swings, and other symptoms are the primary clinical signs of OSA.(1)
Image 1: Pathophysiology of OSA
Pathophysiology of OSA
The exact pathophysiology of OSA is still unknown, but as per research, it has been seen that males are more affected than females with OSA. It depends upon various factors such as age, sex, and BMI (Body Mass Index). Obesity, excessive mass growth on the throat muscle, alcohol, post-menstrual stage, smoking, and partial or complete upper airway obstruction during sleep are some of the risk factors of OSA.
Association of OSA with Glaucoma and Optic Neuropathy
There are several studies that show a strong connection between Glaucoma and OSA. All OSA patients may have Optic Neuropathy, but not all Optic Neuropathy patients have OSA. Differences in intracranial pressure, HTN, DM, ocular perfusion, and hypoxia conditions are the interconnections between OSA and neuro-ophthalmic conditions. Hypoxic conditions affect blood flow. (1)
It may create cerebral vasodilation, which is the main key factor of Retinal Nerve Fiber Layer (RNFL) loss or associated optic nerve diseases. Patients with OSA have a higher chance of developing Normal Tension Glaucoma (NTG) or Primary Open Angle Glaucoma (POAG), along with fluctuations in intraocular pressure throughout the day. (2)
As a result, there is a chance of optic nerve ischemia, which may lead to hypoperfusion of the optic nerve head. Cardiovascular diseases, stroke, and coronary ischemia are major influencing factors of Non-Arteritic Anterior Optic Neuropathy (NAION). (3)
Polysomnography is essential for diagnosing sleep quality in OSA patients, especially those with NAION. Visual field tests are also important in glaucoma and NAION patients linked with OSA. (4)
Treatment
Continuous Positive Airway Pressure (CPAP) is a very effective method to control OSA. It improves physiological sleep, reduces airway blockage, improves cardiovascular conditions, and decreases ocular involvement. Studies show that patients not receiving CPAP have an increased risk of developing NAION.
Conclusion
There is a strong link between OSA and NAION, as well as other optic nerve diseases. Regular monitoring and early diagnosis are crucial. While CPAP reduces NAION risk, it is not a complete solution. Managing systemic conditions such as diabetes, obesity, and hypertension is essential in patients with OSA. (5)
References
- Farahvash, A., & Micieli, J. A. (2020). Neuro-ophthalmological manifestations of obstructive sleep apnea. Eye and Brain, 61-71.
- Sun, M. H., et al. (2018). Association between obstructive sleep apnea and optic neuropathy. Eye, 32(8), 1353-1358.
- Mentek, M., et al. (2018). Retina and optic nerve diseases associated with OSA. Sleep Medicine Reviews, 38, 113-130.
- Madan, S., et al. (2023). NAION and obstructive sleep apnoea. National Medical Journal of India, 36(6).
- Archer, E. L., & Pepin, S. (2013). OSA and NAION. Journal of Clinical Sleep Medicine, 9(6), 613-618.
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