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.
1 The iris is the colored structure of the eye surrounding the pupil. 2  The ciliary body is the muscle that supports the iris and focuses the lens.  The choroid is the layer containing the eye's blood vessels located between the inner retina and the sclera (the white of the eye)