Cataract couching and the goat's eye

Christopher T. Leffler, Stephen G. Schwartz, Eric Peterson, Joshua Busscher

Research output: Contribution to journalArticle


At the start of the third century, a story told by Claudius Aelianus, Leonidas of Alexandria and pseudo-Galen held that couching originated when a goat with cataract punctured its eye with a thorn. The significance of this story is unknown. We reviewed Graeco-Roman texts to identify the relevance of the goat to the eye. In the works of Hippocrates, Aristotle and Galen, the goat's eye was an eye with intermediate brightness or colour. A dark brown eye with a black pupil was healthy and required no treatment. A bright glaukos eye, with extensive corneal edema or scarring, was not amenable to couching. An eye with a white cataract behind an undilated pupil would appear to have an intermediate brightness and was potentially amenable to couching. The origin myth probably arose when an instructor explained that couching works best for a goat's eye, that is, an eye with intermediate brightness.

Original languageEnglish (US)
JournalActa Ophthalmologica
StateAccepted/In press - Jan 1 2018


  • cataract surgery
  • galen
  • glaucoma
  • medical history

ASJC Scopus subject areas

  • Ophthalmology

Fingerprint Dive into the research topics of 'Cataract couching and the goat's eye'. Together they form a unique fingerprint.

  • Cite this