Abstract
Purpose :
The hallmark of non-arteritic anterior ischemic optic neuropathy (NAION) is vascular compromise to the anterior optic nerve and peripapillary retinal nerve fiber layer (pRNFL) thinning and secondary degeneration of the retinal ganglion cell (RGC) body or macular ganglion cell complex (mGCIPL) thinning. This study investigates OCT and OCTA changes in chronic NAION and identifies imaging biomarkers that best predict disease.
Methods :
We performed a retrospective cross-sectional study of 15 chronic NAION patients (20 eyes) and 23 age-matched controls (31 eyes) with swept-source (PLEX® Elite 9000) and spectral-domain OCT imaging, and static perimetry using Humphrey Field Analyzer (all instruments from Carl Zeiss Meditec, Inc, Dublin, CA). OCT pRNFL and mGCIPL were quantified automatically with commercial software, and OCTA were analyzed using custom MATLAB script to measure 12 parameters per eye after large vessel removal: vessel area density (VAD), flux, vessel skeleton density (VSD), vessel complexity index (VCI), vessel perimeter index (VPI), and vessel diameter index (VDI).
Results :
Static perimetry mean deviation (MD) was significantly worse in NAION (-13.53 ± 2.36) than controls (-0.47 ± 0.72; P < .001), with 64 µm thinner pRNFL and 39.7 µm thinner mGCIPL in NAION eyes than controls (P<.001). Spearman correlation analysis show that VAD and flux are highly correlated with visual field MD and OCT measurements. Hierarchical clustering of OCT and OCTA data showed two distinct groups (NAION and control), where standardized measurements for NAION were generally lower than controls. Two-way mixed ANOVAs showed significant interaction between patient status (control and NAION) and structure (optic disc and macula) for annulus VAD and flux values and mean pRNFL and mGCIPL thickness. Post hoc tests showed this effect stems from lower peripapillary values in NAION than controls. Separate logistic regression models with LASSO regularization identified peripapillary VAD, VCI and VDI and macular VAD and flux as the best OCTA parameters to predict NAION.
Conclusions :
Ischemic insult to the peripapillary region is more severe likely from primary degeneration while macula is affected by secondary retrograde degeneration and loss of RGC. Other than structural OCT measurements, peripapillary and macular vascular parameters such as VAD, flux, VCI and VDI are good predictors of optic nerve and retinal changes as a result of NAION.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.