**2. Glaucoma – An optic nerve disease**

ophthalmoscopy revealed several factors, partly optic and partly perceptual, which caused

Later, pathological findings confirmed ophthalmoscopic findings of the optic disc depres‐ sion, what was interpreted as an effect of the elevated intraocular pressure, or- *pressure exca‐ vation of the papilla.* This had profound effect on von Graefe's theory and made him examine all known symptoms of glaucoma and their link with elevated intraocular pressure. This re‐ search turned intraocular pressure from a simple symptom to an "essence" of glaucoma.

First type of glaucoma was acute or inflammatory, which characterized with self-limited prodromal attacks of misty vision (in 70 % of the cases), patient is seeing rainbows around the candle flame; attacks increased in severity, length and frequency until the real disease suddenly erupted in the form of an acute attack of inflammation and severe reduction of vi‐ sion. Partial vision recovery with temporary remission mostly occurred spontaneously or re‐ sponding on a treatment with large doses of opiates, antiphlogisthics and paracenthesis. Many penetrating exams were carried out during the remissions. After analysis of all phases of this type of glaucoma, von Graefe made a concept according which an acute glaucoma is:"achoroiditis or an iridochoroiditis, with diffuse impregnation of vitreous and aqueous with exudative material which caused the rise in pressure through an increase in volume."

Second type was the chronic glaucoma. Prodromal attacks were without any sign of irrita‐ tion, congestion or swelling; lengthen gradually and fused in a chronic form, characterized with the anterior ciliary veins dilatation, shallow anterior chamber, iris atrophy, glaucoma‐

The third type von Graefe simply named amaurosis with excavation of the optic nerve, and for him it was not in a group of glaucomatous diseases[6]. Normal anterior segment, with

Completing this classification, von Graefe used the designation *glaucomatous diseases* for a disorders or conditions which secondarily lead to glaucoma and thereby may result in

In the late period of his research (1861.), von Graefe declared that an exclusion of amaurosis with the optic disc excavation from the group of glaucoma diseases was a mistake[7]. This correction he credited to Doners of Utrecht, his friend, who found a palpable tension among many eyes with so-called amaurosis with optic nerve excavation to be significantly above normal. Doners, after his research, prepositioned a term *glaucoma simplex,* for the glaucoma without anterior segment manifestations and other complications, and *glaucoma with ophthal‐ mia,* for those disorderswhere other manifestations appeared, especially in the anterior seg‐ ment. The common cause of all glaucoma-the elevated intraocular pressure, Doners ascribed

It is interesting that von Graefe discovered also an ocular hypertension patients among his amaurosis with optic nerve excavation cases. He accepted Doner's term glaucoma simplex.

tous cupping, arterial pulsation in the fundus; followed with reduction in vision.

to a hyper secretion of intraocular fluid due to irritation of secretory nerves.

optic disc excavation, which lead to the vision impairment.

blindness.

misinterpretations of relative depth in the fundus.

272 Glaucoma - Basic and Clinical Aspects

Early classification of glaucoma was made at von Graefe's clinic.

In the late 1850s, German anatomist Heinrich Mueller[10] was the first who granted ophthal‐ moscopically observed depression of the optic disc. In his theory that was a result of an ab‐ normally increased vitreous pressure acting upon the lamina and forcing it to recede. Mueller and his followers assumed that the receding lamina had taken the entire papilla with it, placing the nerve fibres on a steadily increasing stretch or pressing them against the sharp edge of the excavation. Consequence of that was optic nerve atrophy.

Considering that this concept was not uniform for all glaucomatous eyes (in some cases pathologists confirmed the lamina cribrosa displacement, in others not), the theory was add to the basic pressure hypothesis and was widely accepted but also a new ophthalmoscopic and pathologic facts of glaucoma were revealed.

Austrian ophthalmologist Isidor Schnabel (1842-1908)[8] was the first to describe in detail the nerve fibre breakdown with the formation of cavities as a characteristic of the glaucoma‐ tous process in the optic nerve. It was the earliest sign and for a long time the only glaucom‐ atous change. In later stages the atrophy affected all portions of the optic nerve up to the entrance of the central vessels. In his opinion, cavernous atrophy was *the* glaucomatous atro‐ phy. Schnabel saw the mechanism of the glaucomatous optic nerve disease in a process of imbibition of pathologic fluid from the vitreous by the nerve fibres, a process independent of the intraocular pressure. His findings were partly confirmed and partly refuted by subse‐ quent investigators.

Another perspective on the origin and nature of the glaucomatous optic neuropathy was in‐ troduced by Priestley Smith[11]. The glaucomatous cup is not a purely mechanical result of exalted pressure, but is in part at least, an atrophic condition which, though primarily due to pressure, includes vascular changes and impaired nutrition in the area of the disc and around its margin which require a considerable time for their full development.

This Priestley Smith's original notion that the rise in pressure may cause damage to the tis‐ sues of the disc through its influence on blood circulation is valid until the present day.
