ABSTRACT
Before the 19th century, much of sickness was treated as a single entity with non-specific bleeding, purging, and blistering to drive out the unnatural or imbalanced phlogistic forces within. Descriptions of specific disease entities burgeoned in the early 19th century, glaucoma among them, with the attribution of elevated intraocular pressure (IOP) to the glaucomatous eye by Demours in 1818 and McKenzie in 1830.1,2 Following Helmholtz’s description of the ophthalmoscope in 1851, Von Graefe described the characteristic appearance of the optic nerve we now call glaucomatous optic neuropathy.3,4 The latter third of the 19th century brought instruments to measure the eye pressure with relative convenience and accuracy. By 1880, physiostygmine and pilocarpine had been shown to reduce IOP in many cases.The first two decades of the 20th century brought modern concepts of surgical management of glaucoma by creating a fistula through the eye wall.Thus, by the early 20th century, both the concept of glaucoma as a pressure-induced disorder and available therapeutic means set the stage for treating glaucoma by reduction of the eye pressure. For the most part, the strategy persists unchanged to this day. By 1950, glaucoma had been subdivided into many of the primary and secondary subtypes we now recognize, but surgical and medical modalities then available comprised the principal methods to reduce IOP in virtually all categories of glaucoma.
