Abstract
Purpose :
Optic disc drusen (ODD) is characterized by semi-translucent deposits on the optic nerve head. ODD causes vision loss and an increased risk of nonarteritic anterior ischemic optic neuropathy. In this study, we quantified structural and blood flow changes in ODD and used principal component analysis, hierarchical clustering and correlation matrix to identify measurements that may predict disease status and visual field (VF) loss.
Methods :
In this retrospective cross-sectional study, we evaluated optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in 29 ODD and 53 age-matched control eyes. The ODD were classified into buried or superficial ODD based on the ophthalmoscopic findings. We used MATLAB scripts to measure vessel area density (VAD), vessel skeleton density (VSD), vessel perimeter index (VPI), vessel complexity index (VCI), flux, and vessel diameter (VD). Statistical analysis was performed using custom R scripts and SPSS.
Results :
Peripapillary and macular VAD was highly correlated with VSD, VPI, and VCI. The principal component analysis revealed 5 key measurements that predicted disease status and VF loss in ODD: retinal nerve fiber layer (RNFL) thickness, macular ganglion cell complex (GCC) thickness, peripapillary VAD, macular VD, and macular flux. Hierarchical clustering of the 5 key measurements vs. all eye clinical characteristics revealed 3 patterns. Eyes without VF loss (static perimetry mean deviation (MD) > -2 dB), which contained mostly control eyes and some of buried ODD or superficial ODD eyes, had normal RNFL, GCC, and peripapillary VAD and low macular VD and flux. ODD eyes with mild VF loss (MD -2 dB to -5 dB), which were mostly buried ODD, had normal RNFL, GCC, and peripapillary VAD and high macular VD and flux. Superficial ODD eyes with moderate/severe VF loss (MD < -5 dB), had low RNFL, GCC, and Disc VAD and high macular VD and flux.
Conclusions :
OCT and OCTA provided objective structural and blood flow measurements that can help predict disease status and VF loss in ODD. Our data predict a model of altered microcirculation in ODD where VF loss is associated with a compensatory increase in macular blood flow before structural thinning of the RNFL and GCC.
This is a 2020 ARVO Annual Meeting abstract.