Eye colors depend on the amount of pigment (melanin) found in the iris and how it is distributed. Light gray-blue eyes contain much less pigment than extremely dark brown eyes. And there are many shades of eye color in between. SEE ALSO: What Determines Hazel Eye Color >.
Dystonia is a movement disorder in which a person's muscles contract uncontrollably. The contraction causes the affected body part to twist involuntarily, resulting in repetitive movements or abnormal postures. Dystonia can affect one muscle, a muscle group, or the entire body.ystonia can affect different body parts, and often the symptoms of dystonia progress through stages. Some early symptoms include: 1  A dragging leg. 2  Cramping of the foot. 3  Involuntary pulling of the neck. 4  Uncontrollable blinking.
1 Secondary dystonia-when dystonia signs and symptoms occur as a consequence of an underlying condition-usually genetic, neurological or an injury which affects the nervous system. 2  Focal dystonia-only one part of the body is affected. 3  Segmental dystonia-two or more regions of the body are affected.ystonia is a general term which describes involuntary movements and extended muscle contractions-a range of movement disorders. The patient has twisting body movements, tremor and unusual or awkward postures.