Development of supersensitivity of the pupil in Horner's syndrome

Abstract

Development of supersensitivity of the pupil to a direct-acting sympathomimetic drug, phenylephrine, was studied in a patient who had a pre-ganglionic lesion after removal of a cervical schwannoma. Supersensitivity of the iris was not demonstrated during the first 17 days after the operation. The result suggests that supersensitivity to sympathomimetic drugs develops somewhat later in man, compared to experimental animals. In these experiments, Mueller's muscle showed clear-cut supersensitivity to phenylephrine on the 12th post-operative day, while supersensitivity of the iris dilator muscle could not yet be demonstrated even on the 17th day. Possible reasons for these discrepancies in time course are discussed.

Key Words:

• Horner's syndrome
• pupil
• denervation supersensitivity