Abstract
Purpose :
To compare alternative methods of using optical coherence tomography (OCT) to follow eyes with or suspected early glaucoma.
Methods :
Patients with or suspected glaucoma had a mean deviation (MD) better than -6 dB on 24-2 VF and 2 OCT (Heidelberg Spectralis SD-OCT) imaging sessions with 3.5mm circle scans of the disc. 109 eyes from 68 patients were included, aged 63.1±15.1 yrs with OCT scans 1.7±0.55 yrs apart. Both summary metrics and automatically defined regions of interest (ROIs)[1] were examined for changes. Summary metrics from the circumpapillary retinal nerve fiber layer (cpRNFL) thickness plot included global (G), temporal (T), temporal superior (TS) and temporal inferior (TI). ROIs were marked based on yellow and/or red regions in the temporal half of the disc on the cpRNFL thickness plots.[2]The width (wROI) and thickness (tROI) were calculated and compared between sessions. The results were analyzed with linear mixed model regression.
Results :
76 of 109 eyes had ROIs in the temporal half of the disc. All of the 4 summary metrics and the wROI method showed significant changes between visits (Table). The G metric showed the most eyes, 29, which significantly worsened. Considering the 10 cases with the most extreme worsening between sessions for G and wROI, only 3 cases overlapped. The 5 of the 7 cases identified by wROI alone had local damage in the cpRNFL (e.g., Fig,1B), while 6 out of 7 cases identified by G alone had diffused damage (e.g., Fig, 1A), indicated by the decrease of the cpRNFL in at least 3 of the 4 sectoral metrics. [In Fig. 1, the light gray curve is cpRNFL thickness from Time 1 (previous scan) and the black curve from Time 2 (current scan). The red dashed rectangles are the computer marked ROIs.]
Conclusions :
Automatic measure of wROIs, as well as global/sectoral metrics, can detect subtle progression. The evidence suggests, however, that both may be needed, as the ROI approach may be best for following local changes, while summary metrics may be better in cases of more diffuse damage. 1. Hood DC et al. JAMA Ophthalmol. 2015; 133: 1438; 2. Wu Z et al. TVST; 2018;7(1):19.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.