Table 2.

Linear spline slopes of each OCT and OCTA metric before and after their respective change points.

	Slope (α)	P value	Slope (β + α)	P value	MD (dB) at Change Point	P value*
OCT Metrics
RNFL, µm	0.790 (0.538 to 1.04)	<0.001	1.72 (1.36 to 2.08)	<0.001	−10.6 (−16.1 to −5.18)	0.009
GCIPL, µm	0.764 (0.106 to 1.42)	0.026	1.08 (0.924 to 1.23)	<0.001	−17.6 (−27.9 to −7.34)	0.332
Peripapillary OCTA Metrics
Custom
pVAD	0.282 (−0.001 to 0.566)	0.051	0.900 (0.754 to 1.05)	<0.001	−12.1 (−16.4 to −7.70)	0.002
Commercial
pPDZ	0.265 (−0.113 to 0.643)	0.142	0.422 (0.365 to 0.480)	<0.001	−17.6 (−31.7 to −3.41)	0.683
Macular OCTA Metrics
Custom
mVAD	-	-	0.698 (0.611 to 0.784)	<0.001	-	-
mVSD	-	-	0.316 (0.276 to 0.357)	<0.001	-	-
Commercial
mPDZ	-	-	0.292 (0.259 to 0.325)	<0.001	-	-
mVDZ	-	-	0.127 (0.117 to 0.138)	<0.001	-	-

^*based on corresponding Davies’ tests

Change-point analyses accounted for inter-eye correlation using linear mixed-effects modeling. α represents the slope of the spline to the left of the change point (i.e., plateau portion of the graph). β + α represents the slope of spline to the right of the change point (i.e., steep portion of the graph). OCTA slope values were multiplied by 100 to enhance readability. α, β + α, and MD at the change point are listed with their corresponding 95% confidence intervals.

MD = mean deviation, OCT = optical coherence tomography, RNFL = retinal nerve fiber layer, µm = micrometers, GCIPL = ganglion cell-inner plexiform layer, OCTA = optical coherence tomography angiography, pVAD = peripapillary vessel area density, pPD^Z = peripapillary perfusion density, mVAD = macular vessel area density, mVSD = macular vessel skeleton density, mPD^Z = macular perfusion density, mVD^Z = macular vessel density