Study: Evaluate young patients with NAION for optic disc drusen
Optic disc drusen may be an independent risk factor for the development of nonarteritic anterior ischemic optic neuropathy in younger patients, according to a study published in the American Journal of Ophthalmology.
“Optic disc drusen (ODD), present in 2% of the general population, have occasionally been reported in patients with nonarteritic anterior ischemic optic neuropathy (NAION),” Steffen Hamann, MD, of the University of Copenhagen department of ophthalmology, and colleagues wrote. “The purpose of this study was to examine the prevalence of ODD in young patients with NAION.”
The retrospective, cross-sectional study involved 65 patients (127 eyes), 49 years old or younger, with NAION. Investigators used ODDS Consortium protocol and enhanced-depth imaging OCT (EDI-OCT) for analysis. They labeled eyes with NAION and ODD as “ODD-AION” and eyes without ODD as “NODD-AION”.
Of 74 eyes with NAION, 51% had ODD-AION while 43% of fellow eyes without NAION had ODD. Hamann and colleagues did not find significant differences between eyes with ODD-AION and eyes with NODD-AION in regard to visual acuity or perimetric mean deviation. EDI-OCT results showed 28% of eyes with NODD-AION had peripapillary hyperreflective ovoid mass-like structures vs. 54% of eyes with ODD-AION (P = .006), and 7% with NODD-AION had hyperreflective lines vs. 66% with ODD-AION (P < .001).
“This study identied a prevalence of ODD in young NAION eyes that was signicantly higher than expected compared to the general population. Many cases of ODD were not detectable on ophthalmoscopy and required diagnosis by EDI-OCT,” Hamann and colleagues concluded. “These authors propose that ODD-AION be recognized as an entity separate from NODD-AION, and that ODD should be expressly looked for in all cases of young NAION.”
Perspective
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NAION is a common cause of acute vision loss in patients older than 50 years but is quite uncommon in those younger than 50 years. As such, the risk factors for this specific cohort of patients with NAION has not been as well studied.
While subject to biases inherent to retrospective studies, this well-designed study lays out convincing evidence that we can and should be routinely utilizing EDI-OCT of the optic nerve to look for optic disc drusen in our younger patients with acute optic neuropathy, even in the setting of acute disc swelling. With a prevalence of optic disc drusen dramatically higher than the general population, the results suggest that optic disc drusen are a risk factor for NAION in younger patients. The authors acknowledge that excluding patients with substandard or no optic nerve EDI-OCT may have increased the prevalence of disc drusen found, but they convincingly argue that had every one of those excluded patients been included and negative for disc drusen, the prevalence would still have been many times higher than the general population.
That said, NAION in a person younger than 50 years should be a diagnosis of exclusion, even in the setting of optic disc drusen or vasculopathic risk factors. This study in no way argues that the presence of optic disc drusen in a young patient with acute optic neuropathy obviates the need for urgent work-up to rule out treatable underlying etiologies.
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