Kocher's sign is a medical sign that denotes an eyelid phenomenon in

hyperthyroidism Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland. Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidism ...

and

Basedow's disease Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an goitre, enlarge ...

. In fixation on a fast upwards movement there occurs a convulsive retraction of the eyelid.

References

Endocrinology {{Med-sign-stub