This is a "copper wire" artery  (pale section of normally red artery) and it indicates that the blood flow is restricted due to fatty deposits in the artery wall. The likley cause is hardening of the arteries.

This Gunn-Salus crossing is an example of a ridgid artery wall.  The artery wall is pressing on the vein causing it to deflect from its path in a zig zag pattern.  This compression of the vein can cause a stroke.

This more severe Gunn-Salus crossing is an example of a ridgid artery wall.  The artery wall is pressing on the vein causing it to deflect from its path in a zig zag pattern.  This compression of the vein is so severe that the vein is almost closed off at the crossing.

This is High Blood Pressure.  You will note that the artery is much smaller in caliber than the vein. It is almost 1/2 the size of the vein.  In normal healthy vessels the ratio of  size of the artery to vein should be 2:3 (not 1:2 as seen here).

This is picture of diabetic micro aneurysms.  An aneurysm is a balloning of the end of a blood vessel that can burst and bleed.  In diabetics, who do not take optimal care of their health,  the blood vessels begin to fail  as shown here. The tiny white triangle points to an exudate,  which is fluids that leak from the compromised vessels.