The Origin of the Term Glaucoma: Owls or Light-colored Eyes?
Laios et al1 recently proposed an idea for the origin of the term glaucoma in ancient Greece. They speculate that because the owl (Glaux) has good vision, ancient authors might have believed that the owl could ward off eye disease, which then was described with a related term (glaucoma).1
The authors accept that both terms were derived from the color term glaukos.1 Maxwell-Stuart compiled hundreds of uses of glaukos, and related terms, by 120 ancient authors.2Glaukos described green, gray, or light blue objects.2–4Glaukos most commonly described healthy eyes that were not dark (63 total authors, 39 in prose, and 24 in verse).3,4 The glaukos eye of the Northern European was a minority in the ancient Mediterranean world, and evoked a variety of negative cultural stereotypes.2–4 We concede that among the works of 63 authors who wrote about the healthy glaukos eye, one can find one solitary figure (the goddess Athena) who was associated with the owl.
Glaukos, and variant terms, were used to describe a variety of animals: horses (6 authors), lions (4 authors), leopards, snakes, dogs, and owls (2 authors each).2,3Glaukos also described the sea (29 authors), plants (19 authors), the moon (6 authors), gems, and the sky (5 authors each).2,3
Diseased eyes were described as glaukos, or related variants, by 12 ancient authors, including Galen of Pergamon.2–4 These 12 authors typically also used the term glaukos in its more common sense, to describe healthy light-colored eyes.2–4 Two authors (Antiochus and Vettius Valens) related diseased glaukos eyes to the phase of the moon.2 None of the 12 authors explicitly related diseased glaukos eyes to the owl.2,3 The proposed origin of the term glaucoma with the owl does not clarify which diseases might have plausibly been described as glaucoma.
Our analysis does provide insight: diseased eyes which appeared lighter (green or gray) than normal were considered glaukos. Hippocrates, Aristotle, and Agatharcides described this change in the elderly.2–4 Before the era of couching, most such diseases were incurable, and would have included dense white cataracts, which can be seen even with a small pupil. We have emphasized that such cases would also have included angle-closure glaucoma, because the mid-dilated pupil can appear green or gray.3–5 Other conditions could have been represented as well, such as phthisical eyes with corneal edema.
With the Common Era, couching became more widely known in the Mediterranean world. The glaukos hue had such a negative connotation that it continued to describe incurable cases, according to Demosthenes Philalethes, Rufus of Ephesus, and Apsyrtos of Bithynia.2–4 A new term was invented (hypochyma) for the condition which responded well to couching. Today, we understand that couching displaces the opacified crystalline lens, but the ancient authors believed that couching displaced an opacity anterior to the lens.
Beginning with the early 18th century, various authors provided more complete descriptions of angle-closure glaucoma, with a palpably hard eye, pain, conjunctival injection, a fixed, dilated, green or gray pupil, an anteriorly prominent crystalline lens, a convex iris bowing forward, a narrow anterior chamber, and difficulty in cure.4 Many authors called this condition glaucoma, in the tradition of the ancient Greek authors who described the light-colored eye as glaukos.4 The development of the ophthalmoscope in 1850 permitted visualization of the excavated optic neuropathy both in angle-closure glaucoma, and in eyes with a normal external appearance (most of which had primary open-angle glaucoma).4 The role of elevated intraocular pressure became better accepted in these conditions, both of which came to be called glaucoma.4
Laios et al1 cited almost exclusively modern texts.