Symptoms depend on which muscles are affected. For example, when weakness affects muscles of the chest, people may have difficulty breathing. When weakness affects muscles that control the eyes, people may have double vision. Complete muscle weakness causes paralysis.
The choroid is the layer of blood vessels and connective tissue between the sclera (white of the eye) and retina. It is part of the uvea and supplies nutrients to the inner parts of the eye.
The posterior portion of the uveal tract is represented by the, a vascular membrane that separates the fibrous layer from the retina. The choroid receives its blood supply from the central retinal artery that emerges from the back of the eye.The choroid provides all eye layers with 90% of their blood supply.The blood vessels, embedded in a meshwork of connective tissue, supply the fibrous layer and much of the retina with nutrients.he choroid provides all eye layers with 90% of their blood supply. The blood vessels, embedded in a meshwork of connective tissue, supply the fibrous layer and much of the retina with nutrients.