Figure 4. Relations of neural and vascular
parameters for 50/10 model (red), 75 model (green), and control (blue)
rats. Symbols indicate age at test (key). Postreceptor sensitivity, Sm,
is plotted as a function of rod photoreceptor sensitivity, Srod
(top panel). Arteriolar tortuosity (TA) is plotted as
a function of Srod (middle panel) and Sm
(bottom panel). The left ordinates and bottom abscissae are expressed
in derived (Equation 5) ΔLogNormal units; the right ordinates
and top abscissae are linear values. Stippled lines indicate the means
for the P25–P26 controls. Solid lines are orthogonal linear regressions
through all the data. Low Srod was significantly
related to low Sm (r=0.35; p=0.009) and high TA
(r=-0.40; p=0.003). Low Sm was also significantly
related to high TA (r=-0.62; p<0.001).