Abstract
Purpose :
The region labeled “less vulnerable” in Fig. 1 is often the last to be affected in patients with severe glaucoma.[1,2] In this study, we ask whether measures of this region are more effective than average circumpapillary retinal nerve fiber layer (cpRNFL) thickness for detecting progression in eyes with severe glaucoma.
Methods :
38 eyes from 36 patients with sdOCT (3D-OCT 2000, Topcon, Inc) disc and macula cube scans across at least two visits were selected from a database of glaucoma patients with 24-2 visual field mean deviations worse than -12dB. For the macula analysis, 43 pairs of intra-visit and 29 pairs of inter-visit macula cube scans (2.6±1.8 yrs on average between visits) of acceptable quality were included. Average ganglion cell complex (GCC) thickness, average retinal ganglion cell plus inner plexiform layer (RGC+) thickness, and percent area of significant thinning (PAST), defined as the percentage of the macula cube scan with cpRNFL thickness less than the 5th percentile of control values, were calculated for the macula (central ±8°), as well as the more and less vulnerable macular regions (Fig. 1). For the circumpapillary analysis, 42 pairs of intra-visit and 24 pairs of inter-visit disc scans (2.7±1.9 years between scans) of acceptable quality were included. Average global cpRNFL and quadrant (superior, temporal, inferior, nasal) thicknesses were calculated. An inter-visit scan difference that exceeded the 95th percentile of the corresponding intra-visit measure was considered to represent progression.
Results :
Of the macula measures (Table 1A), the less vulnerable average GCC thickness showed the largest number of progressing eyes (11 of 29). Of the disc measures (Table 1B), the temporal cpRNFL quadrant had the largest number of progressing eyes (6 of 24).
Conclusions :
The average GCC thickness of the less vulnerable macula region may be the most effective measure for detecting progression in advanced glaucoma, consistent with the preservation of this region until late in the disease process. As expected, among the cpRNFL metrics, the temporal thickness, which corresponds to the less vulnerable macula region, performed the best. 1. Hood et al., PRER, 2013. 2. Weber et al, Int. Ophthal, 1989
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.