This site uses tracking information. Visit our privacy policy. Click to agree to this policy and not see this again.

Ophthalmology and Visual Sciences

Tadpole Pupil

Tadpole Pupil

Category(ies): Neuro-ophthalmology, Iris
Contributor: Kristina Damisch, M2 and Lorraine Provencher, MD

A tadpole pupil (pictured below, right eye) occurs with segmental spasm of the iris dilator muscle producing episodic pupillary distortion, often in the shape of a tadpole. Dr. Stan Thompson of the University of Iowa, Department of ophthalmology, first coined this phenomenon as a "tadpole pupil" in 1983. This intermittent, irregular mydriasis usually lasts less than five minutes but has been described to last up to 15 minutes. It may occur several times per day, over several days to weeks. Tadpole pupil usually resolves without recurrence, but it does have a strong association with the subsequent development of a Horner's Syndrome. Tadpole pupil has also been associated with Adie tonic pupil and migraines. Hence, clinicians should consider additional workup for these entities.

References:
  1. Balaggan KS, Hugkulstone CE, Bremner FD. Episodic segmental iris dilator muscle spasm: the tadpole-shaped pupil. Arch Ophthalmol. 2003;121(5):744-745.
  2. Thompson HS, Zackon DH, Czarnecki JS. Tadpole-shaped pupils caused by segmental spasm of the iris dilator muscle. Am J Ophthalmol. 1983;96(4):467-77.

Image Permissions:
Creative Commons

Ophthalmic Atlas Images by EyeRounds.org, The University of Iowa are licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.