Cataract couching and the goat's eye.

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.

Enduring influence of elizabethan ophthalmic texts of the 1580s: bailey, grassus, and guillemeau.

Three English ophthalmic texts of the 1580s were frequently republished: 1) Walter Bailey's A Briefe Treatise Touching the Preseruation of the Eie Sight, 2) The Method of Phisicke, an adaptation of the medieval treatise of Benevenutus Grassus, and 3) A Worthy Treatise of the Eyes, a translation of Jacques Guillemeau's treatise. Their history is intertwined through composite publications, some of which lacked clear attribution. At least 21 editions incorporated these texts. Although not previously realized, major elements of all 3 works are found in Two Treatises Concerning the Preseruation of Eie-sight, first published in 1616. To preserve eyesight, Bailey recommended eyebright (Euphrasia officinalis), fennel (Fæniculum vulgare), and a moderate lifestyle incorporating wine. In the works of Grassus and Guillemeau, cataracts were believed to lie anterior to the 'crystalline humor,' and were treated by the 'art of the needle,' or couching. Links are found between Grassus, Guillemeau, and eighteenth century glaucoma concepts. Although one of his students has traditionally received credit, it was English oculist John Thomas Woolhouse who first combined the early concepts and used the term glaucoma to describe the palpably hard eye in the early eighteenth century. The three primary ophthalmic texts of 1580s England influenced ophthalmic thought for over a century.