Atlas of Ophthalmology

Tonic Pupil

Tonic Pupil
Top:The anisocoria in this patient is due to a tonic pupil in the right eye, based on the concurrence of sectoral palsy of the iris sphincter and denervation supersensitivity to weak-strength miotics. Bottom: When the patient fixates on a near target, the dilated right pupil constricts slowly and progressively until it becomes slightly smaller than the simultaneously constricted left pupil. This is an example of light-near dissociation. In patients with unilateral or bilateral tonic pupils, light-near dissociation is due to aberrant reinnervation of the paretic iris sphincter muscle by fibers that originally innervated the ciliary muscle.
Pollock, Stephen C. , M.D., ¦1, Mebane NC, USA
H57.0
Neuro-Ophthalmology -> Pupillary Abnormalities -> Neurogenic Disorders -> Tonic Pupil
5833
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