It's caused by inflammation in the uvea, a layer of tissue just inside the outer white part of your eye. The uvea is made up of a layer of blood vessels, a muscular ring that surrounds your pupil ...

Researchers at Mass General Brigham have identified new biomarkers for tinnitus by measuring pupil dilation and subtle facial movements that correlate with the level of distress caused by the disorder ...

“Natural muscle has multiple orientations in the tissue, but we haven’t been able to replicate ... The iris comprises a ring of muscle surrounding the pupil. This ring of muscle is made up of an inner ...