Figure 6. Correlation between age and standard combined b-wave amplitudes and between age and standard combined b/a-wave ratio in patients with XLRS. Black points represent eyes. A: Low negative correlation was detected between age and standard combined b-wave amplitudes of full-field ERG. B: There was no correlation detectable between age and standard combined b/a-wave ratio of full-field ERG. Negative type ERG (b/a ratio ≤1) was detected in half of the group of eyes.