TABLE 5.

The RNFL Broken-stick Model With Associated Slopes Above and Below the Tipping Point, the Point at Which RNFL Thinning is First Associated With Visual Field Damage

Anatomic Region	Slope Below the Tipping Point [95% CI] (dB/μm)	P*	Slope Above the Tipping Point [95% CI] (dB/μm)	P†	Difference Between Slopes Below and Above the Tipping Points (dB/μm)	P‡
Global	0.276 [0.192, 0.360]	<0.001	0.04 [−0.095, 0.177]	0.275	0.235	0.002
Superior	0.314 [0.217, 0.412]	<0.001	0.018 [−0.132, 0.168]	0.407	0.297	0.001
Inferior	0.400 [0.291, 0.509]	<0.001	0.057 [−0.105, 0.219]	0.243	0.343	<0.001
Nasal	0.216 [0.129, 0.302]	<0.001	0.072 [−0.094, 0.239]	0.195	0.144	0.066
Temporal	0.399 [0.268, 0.531]	<0.001	0.063 [−0.130, 0.256]	0.239	0.336	0.003
Superior-nasal	0.390 [0.245, 0.535]	<0.001	0.041 [−0.173, 0.255]	0.352	0.349	0.004
Superior-temporal	0.225 [0.140, 0.310]	<0.001	0.027 [−0.111, 0.165]	0.350	0.198	0.008
Inferior-nasal	0.321 [0.236, 0.406]	<0.001	0.025 [−0.113, 0.162]	0.362	0.296	<0.001
Inferior-temporal	0.362 [0.262, 0.462]	<0.001	0.039 [−0.111, 0.188]	0.305	0.323	<0.001

All P-values are taken as statistically significant when P<0.05.

^*P-values for the slopes below the tipping points represent the statistical significance of the slopes being different than 0.

^†P-values for the slopes above the tipping points represent the statistical significance of the slopes being different than 0.

^‡P-values for the last column represent the statistical significance of the difference between the slopes below the tipping points and above the topping point.

CI indicates confidence interval; RNFL, retinal nerve fiber layer.