Abstract
Purpose :
We have previously demonstrated that macular superpixels thickness measurements have high and uniform reproducibility regardless of the layer thickness. We herein test the hypothesis that the full macular thickness (FMT) or ganglion cell complex (GCC) measurements are better able to detect glaucoma progression given the lower relative measurement noise.
Methods :
125 eyes showing signs of macular and central perimetric damage with ≥2 years of follow-up and ≥5 macular OCT and 10-2 visual field (VF) tests were selected. The central 24 OCT superpixels and VF test locations were matched after correction for retinal ganglion cell displacement. We calculated macular structural rates of change over time for the ganglion cell layer (GCL), ganglion cell/inner plexiform layer (GCIPL), GCC, and FMT with univariate linear regression. We compared proportion of superpixels with significant rates of change (slope <0 or >0 µm/year and p <0.05) among the 4 macular parameters. We also explored the relationship between baseline superpixel thickness or corresponding total deviation (TD) value with structural rates of change. We defined VF progression as a change of 3 dB in 10-2 mean deviation and compared rates of structural change in stable and progressing eyes.
Results :
The average 10-2 mean deviation was –8.9 (±6.0) dB and the median (IQR) follow-up was 3.6 (3.2-4.1) years. The proportion of worsening superpixels based on GCL, GCIPL, GCC, FMT rates of change were 9.9%, 14.1%, 18.8%, and 26.6%, respectively (p<0.001 for all pairwise comparisons). The corresponding proportions for improving superpixels were 3.2%, 3.1%, 2.7%, and 1.8% (p<0.012 for all comparisons to FMT). The average significant slopes were –1.4, –1.8, –2.0, and –2.5 µm/year for GCL, GCIPL, GCC, and FMT, respectively (Figure). The baseline TD or superpixel thickness were not related to the magnitude of rates of change (p>0.124 and >0.924 with Bonferroni correction). The average rates of change were significantly faster in eyes with VF progression (20 eyes) compared to stable eyes (p<0.001).
Conclusions :
FMT and GCC thickness measures detected more deteriorating superpixels compared to GCIPL and GCL parameters in this group of eyes. The former parameters may be better suited for detection of progression of central glaucomatous damage. The rates of change for macular parameters did not vary as a function of baseline superpixel thickness or threshold sensitivity.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.