The early history of glaucoma: the glaucous eye (800 BC to 1050 AD)
By Christopher T Leffler, Stephen G Schwartz, Tamer M Hadi, Ali Salman and Vivek Vasuki
Clinical Ophthalmology, No.9 (2015)
Abstract: To the ancient Greeks, glaukos occasionally described diseased eyes, but more typically described healthy irides, which were glaucous (light blue, gray, or green). During the Hippocratic period, a pathologic glaukos pupil indicated a media opacity that was not dark. Although not emphasized by present-day ophthalmologists, the pupil in acute angle closure may appear somewhat green, as the mid-dilated pupil exposes the cataractous lens. The ancient Greeks would probably have described a (normal) green iris or (diseased) green pupil as glaukos. During the early Common Era, eye pain, a glaucous hue, pupil irregularities, and absence of light perception indicated a poor prognosis with couching. Galen associated the glaucous hue with a large, anterior, or hard crystalline lens. Medieval Arabic authors translated glaukos as zarqaa, which also commonly described light irides. Ibn Sina (otherwise known as Avicenna) wrote that the zarqaa hue could occur due to anterior prominence of the lens and could occur in an acquired manner. The disease defined by the glaucous pupil in antiquity is ultimately indeterminate, as the complete syndrome of acute angle closure was not described. Nonetheless, it is intriguing that the glaucous pupil connoted a poor prognosis, and came to be associated with a large, anterior, or hard crystalline lens.
Excerpt: Galen of Pergamon (c 129–199 AD) was one of the most prolific and influential ancient medical authors. His theory of eye colors was similar to that of Aristotle, in that a lesser amount of fluid in the eye resulted in a brighter hue (glaukos), while more fluid would be darker, just as is deep water. Galen added that the crystalline humor, unknown in Aristotle’s time, was itself a light source, and the glaukos hue was more likely if the crystalline was thicker, anteriorly located, or hard. This could be seen in the corneal reflection, which Galen believed to emanate from the crystalline humor. Galen wrote in Ars Medica a passage also recorded by Oribasius:
As far as the color [χρόαν, chroan] of the eye is concerned we have to differentiate the following: The eye will appear blue [γλαυκòς, glaukos] either because of the size and the brightness of the crystalline lens or because the lens is located more anteriorly; similarly it can be due to not enough or not pure enough watery fluid in the pupil. If all these conditions are fulfilled the eye will appear in a saturated blue [γλαυκότατος, glaukotatos]. If some of the conditions are present but others not then the eye will demonstrate variations of blue [γλαυκότητι, glaukoteti]. A black [Μέλας, melas] eye has either a small crystalline lens or the lens is deeply located or has incomplete brightness; it can also be due to an ample amount of aqueous fluid or because the fluid is not pure.