In the Journals

Study shows strong correlation between NAION, obstructive sleep apnea

A large retrospective, longitudinal cohort study based on the national health insurance database of Taiwan found significant correlation between nonarteritic anterior ischemic optic neuropathy and obstructive sleep apnea.

The data covered the period 1996-2013, during which 8,488 cases of obstructive sleep apnea (OSA) were reported. In this population, the overall rate of nonarteritic anterior ischemic optic neuropathy (NAION) was 0.36%, while in the 33,952 subjects of the control group the rate was 0.2%.

Multivariate COX regression analysis showed that the subjects with OSA had a significantly higher risk of developing NAION within the 18 years of the study. The biggest difference in risk rate between patients with OSA and controls was found in the 30- to 39-year-old age group, while the peak percentage of NAION in the OSA group was in the 70- to 79-year-old age group.

NAION presents with sudden-onset, painless visual loss on awakening in the morning, due to ischemic damage of the optic nerve with variable degrees of severity.

The mechanism by which OSA may provoke NAION is unclear. It might include hypoxia and compression of the optic nerve or oxidative stress impairing the functionality of the arteries that nourish the optic nerve. Variations in ocular perfusion pressure and imbalance between vasoconstrictive and vasodilatory agents might also play a role, the authors explained.

The strong association between NAION and OSA found in this study suggests that OSA may contribute to the development of NAION.

“Therefore, OSA should be screened in NAION patients and then treated once the diagnosis is confirmed given that management for OSA may help prevent new NAION events in the fellow eye,” the authors wrote. – by Michela Cimberle

Disclosure: The authors reported no relevant financial disclosures.

A large retrospective, longitudinal cohort study based on the national health insurance database of Taiwan found significant correlation between nonarteritic anterior ischemic optic neuropathy and obstructive sleep apnea.

The data covered the period 1996-2013, during which 8,488 cases of obstructive sleep apnea (OSA) were reported. In this population, the overall rate of nonarteritic anterior ischemic optic neuropathy (NAION) was 0.36%, while in the 33,952 subjects of the control group the rate was 0.2%.

Multivariate COX regression analysis showed that the subjects with OSA had a significantly higher risk of developing NAION within the 18 years of the study. The biggest difference in risk rate between patients with OSA and controls was found in the 30- to 39-year-old age group, while the peak percentage of NAION in the OSA group was in the 70- to 79-year-old age group.

NAION presents with sudden-onset, painless visual loss on awakening in the morning, due to ischemic damage of the optic nerve with variable degrees of severity.

The mechanism by which OSA may provoke NAION is unclear. It might include hypoxia and compression of the optic nerve or oxidative stress impairing the functionality of the arteries that nourish the optic nerve. Variations in ocular perfusion pressure and imbalance between vasoconstrictive and vasodilatory agents might also play a role, the authors explained.

The strong association between NAION and OSA found in this study suggests that OSA may contribute to the development of NAION.

“Therefore, OSA should be screened in NAION patients and then treated once the diagnosis is confirmed given that management for OSA may help prevent new NAION events in the fellow eye,” the authors wrote. – by Michela Cimberle

Disclosure: The authors reported no relevant financial disclosures.

    Perspective
    Mark Sawamura

    Mark Sawamura

    NAION can be thought of as being caused by everything but giant cell arteritis. As a vasculopathic-based condition, these patients can present with a multitude of risk factors, and identifying the exact cause can be difficult, especially when its pathophysiology is still up for debate. Of note, it has been well established that OSA can have a negative influence on papillary hemodynamics.

     There are a couple of important things to consider in this study. First, this was an investigation whose patient population is exclusively Asian. Second, the study primarily followed patients between 30 and 60 years of age mainly because sleep apnea was diagnosed in this population. There were patients in the 60- to 69-year, 70- to 79- and 80+ year age groups, but they were in smaller numbers. As the patient populations aged, there was also an increase in other vasculopathic risk factors. It was noted in the discussion of the paper that several investigators have found that East Asian patients diagnosed with sleep apnea tend to be younger and present with the more severe stages of the disease.

     I would agree with the authors that younger patients who present with NAION should be screened for OSA and appropriately managed to reduce the risk of bilateral ocular involvement.

    • Mark Sawamura, OD, FAAO
    • Associate professor, chief of the Jarnagin Center for Primary Eye Care and chief of the Ocular Disease Service
      University Eye Center at Ketchum Health
      Marshall B. Ketchum University
      Southern California College of Optometry

    Disclosures: Sawamura reports no relevant financial disclosures.