Abstract
Purpose :
Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common cause of acute optic neuropathy in patients over age 50, causing often-devastating effects on vision. However, understanding of the pathophysiology of NAION is limited. We performed a prospective clinical study to generate the first comprehensive characterization of retinal microstructure, microcirculation, microvascular networks, and ganglion cell function in patients with acute NAION.
Methods :
5 patients (3 female/2 male, age range 46-70, mean age 59) with acute NAION underwent pattern electroretinogram (PERG), retinal functional imaging (RFI), optical coherence tomography angiography (OCTA), and ultra high resolution optical coherence tomography (UHR-OCT) at intervals of 2 weeks, 1 month, and 3 months after the onset of vision loss. Images were processed according to previously established techniques. Results were evaluated using Microsoft Excel.
Results :
5 patients with acute NAION were enrolled and underwent imaging. 2 patients withdrew after the 1-month imaging session, and 3 patients completed imaging. RFI demonstrated a trend toward decreasing retinal blood flow velocity over time after NAION. PERG showed decreased retinal ganglion cell function that improved over time while remaining subnormal. Compared with a normative database of 30 patients (age range 25-79, mean 39), amplitude was diminished, whereas phase remained comparable to controls. PERG amplitude of NAION patients was 29%, 32%, and 36% (p=0.00008, 0.0002, and 0.0000001, respectively) that of controls at the 2-week, 1-month, and 3-month imaging sessions, whereas phase represented 101%, 100%, and 98% of controls at the same time intervals (not statistically significant). OCTA demonstrated an increase in superficial microvascular network complexity after NAION, and a decrease in deep microvascular network complexity. Retinal nerve fiber layer and ganglion cell layer thickness declined between weeks 2 and 4, then plateaued. Time point comparisons did not reach statistical significance.
Conclusions :
Results demonstrate the feasibility of comprehensive characterization of NAION using a full suite of advanced ophthalmic imaging techniques. A larger sample size and comparison to age-matched controls will be required for further correlations to be established.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.