Two Cases of Tonic Pupil: Ross and Ross Syndrome Plus

Ross syndrome is a rare disorder of the peripheral autonomic nervous system characterized by a triad of tonic pupils with light-near dissociation, segmental anhidrosis, and areflexia. Though having a benign course, the disease can cause significant social embarrassment. Both our cases presented with complaints of segmental facial hyperhidrosis. The first case with a one-year history had findings of segmental anhidrosis up to T4 thoracic level, left tonic pupil, and absent right ankle reflex. While the second case with a history of five years had bilateral tonic pupil, absent lower limb reflexes, anhidrosis of left face, neck, and upper trunk up to T4 level, apart from having associated Horner’s syndrome. Minor’s (starch-iodine) test and dilute pilocarpine test were helpful for diagnosis in both cases, indicating areas of anhidrosis and pupillary cholinergic denervation hypersensitivity respectively. Both cases were provided counseling and managed conservatively.