Diseased Bird: sick bird?

Today I saw this Red-Winged Blackbird at my house eating from the ground, an unusual sight to see right in my yard I grabbed my camera, when zoomed in I noticed his eye didn’t look right and thought he could be sick? There were no other blackbirds, or even grackles or starlings around that I saw, just him, and have only seen him just today. There is no one around here I know to call if he is sick. He did not eat at any feeders but he did eat off the ground. Should I be worried for my other birds?