Abstract
Purpose :
To identify and understand patterns of progressive, glaucomatous damage around the circumpapillary retinal nerve fiber layer (cpRNFL) using optical coherence tomography (OCT) circle scans and custom cpRNFL thickness difference plots.
Methods :
116 eyes [86 early glaucoma, 30 healthy controls (HC)] from 116 patients were identified from a prospective, longitudinal study and comprised the study group (SG). Eyes had baseline OCT disc circular and macular cube scans and a follow-up scan at least 1 year from the baseline date. RNFL thickness difference plots (Fig. 1C) were generated using a custom program to show the change in cpRNFL thickness between the first baseline (Fig. 1A) and most recent (Fig. 1B) circle scans. Fig. 1C shows an example with 95% confidence interval (dotted curves) based upon short-term variability in 176 eyes using all tests within 4 months of baseline. For the 116 eyes in the SG, an OCT expert identified 15 definite progressing eyes (P) and 68 definite non-progressors (NP), after evaluation of the OCT information. Patterns of progressive RNFL changes in the P eyes were defined based upon the difference plots. A mixed-effect linear model was used to assess sector differences among the HC, P and NP groups.
Results :
Progression was present in the inferior disc in 14 of the 15 P eyes, and always included the TI region. However, 11 of the 15 P eyes showed significant progression in both the inferior and superior disc on the difference plots, while progression was restricted to one hemidisc in the other 4. 3 of these 4 showed static glaucomatous damage in the non-progressing hemidisc. Only 1 eye had both damage and progression confined to a single hemidisc. None of the eyes had significant diffuse damage, defined as significant progression in all regions of the disc on the difference plots. However, for all regions of the disc, except the nasal region, the P group, but not the NP group, showed statistically significant progression as compared to the HC group (Fig. 2).
Conclusions :
In early glaucoma, most of the RNFL loss due to progression tended to be relatively local. While in general inferior and superior regions of the disc were involved, in 14 of the 15 P eyes progression included the TI region of the disc, a region susceptible to early glaucomatous damage [1,2]. 1. Hood et al., PRER, 2013. 2. Hood PRER 2017.
This is a 2021 ARVO Annual Meeting abstract.