Table 3.

Paired Comparison of ERG Responses Tested at the Null Region and AFN

Parameters	Null Point	AFN	Difference	Upper LoA	Lower LoA	Percentage Difference	P Value
Photopic SF
a-Wave amplitude (log µV)	1.56 ± 0.16	1.56 ± 0.15	0.000	0.196	−0.196	−0.32%	0.856
b-Wave amplitude (log µV)	2.10 ± 0.11	2.08 ± 0.12	0.010	0.088	−0.068	0.69%	0.221
a-Wave peak time (msec)	14.1 ± 1.45	14.0 ± 1.50	0.120	1.747	−1.507	0.85%	0.559
b-Wave peak time (msec)	28.6 ± 1.89	28.4 ± 1.93	0.190	0.817	−0.437	0.67%	0.027
Scotopic DIM
b-Wave amplitude (log µV)	2.39 ± 0.14	2.40 ± 0.20	−0.010	0.284	−0.304	−0.43%	0.817
a-Wave peak time (msec)	39.1 ± 5.70	39.9 ± 4.37	−0.760	9.295	−10.815	−1.95%	0.615
b-Wave peak time (msec)	94.5 ± 15.4	99.9 ± 19.2	−5.350	15.426	−26.126	−5.67%	0.105
Scotopic SF
a-Wave amplitude (log µV)	2.26 ± 0.12	2.17 ± 0.13	0.080	0.315	−0.155	3.63%	0.023
b-Wave amplitude (log µV)	2.57 ± 0.10	2.52 ± 0.11	0.040	0.177	−0.097	1.86%	0.027
a-Wave peak time (msec)	19.1 ± 3.01	19.9 ± 2.96	−0.720	4.062	−5.502	−3.79%	0.268
b-Wave peak time (msec)	48.9 ± 4.03	50.1 ± 5.01	−1.140	5.132	−7.412	−2.34%	0.173

AFN, away from the null region.

The data show are mean ± SD. The data in the percentage difference column are calculated using the formula % difference = (Data (Null) – Data (AFN))/(Data (Null)) × 100%. The positive difference means that the response obtained from the null region is larger (amplitude) or longer (peak time) than the data collected from the region AFN. The negative data means the data gained at the null region is smaller (amplitude) or shorter (peak time) compared with the data from the position AFN. P values are not adjust across statistical models.

LoA, limits of agreement.