Abstract
Purpose :
The correlation between the retinal nerve fiber layer (RNFL) as measured by Optical Coherence Tomography (OCT) with vascular abnormalities measured by OCT Angiography (OCTA) in early stages of glaucoma is still not completely understood. The purpose of this retrospective case series is to compare OCT with OCTA in its ability to differentiate two glaucoma groups: early stage Primary Open Angle Glaucoma (POAG) and Normal Tension Glaucoma (NTG), from Ocular Hypertension (OHT) and glaucoma suspects by optic nerve head appearance (GS).
Methods :
Patients of the USC Roski Eye Institute between 2017-2020 with a diagnosis of early POAG, early NTG, OHT, or GS as determined by International Classification of Disease codes were included if both an OCT-RNFL and a 6mm x 6mm Spectral Domain OCTA of the optic nerve head were completed during the same office visit. RNFL thickness, Vessel Area Density (VAD), and Flux were compared on average and by retinal quadrant between each glaucoma type versus OHT and GS. A one-way Analysis of Variance was performed to establish significant differences between glaucoma and suspect groups.
Results :
46 eyes (9 POAG, 8 NTG, 21 OHT, 8 GS) from 46 patients were included. Significant differences in average RNFL thickness were found between OHT and GS with POAG (F(2,35)=[8.5], p<0.001) and OHT and GS with NTG (F(2,34)=[5.5], p=0.008). Table 1 depicts quadrant specific RNFL thickness comparisons between POAG and suspects, as well as NTG and suspects. There were no significant differences found in average Flux between POAG and OHT and GS or between NTG and OHT and GS. Table 2 depicts quadrant specific Flux comparisons between these groups. There were no significant VAD differences, on average or by quadrant, found between either POAG or NTG eyes with OHT or GS eyes.
Conclusions :
OCT-RNFL demonstrated significant differences between both early POAG and NTG eyes from eyes with OHT or GS. OCTA demonstrated significant differences in Flux between early POAG and NTG eyes from eyes with OHT and GS. Future studies are needed to determine the utility of these modalities as biomarkers of early glaucoma phenotypes.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.