**16. Perimetry**

ciple to mechanical tonometry, he expected "…very little from this test since digital tonome‐

Although Grafe is credited with the first attempts to create instruments that mechanically measured IOP in the early 1860s, his proposed instruments were neither designed nor built. Rather, it was Donders who designed the first instrument capable of estimating IOP – albeit not accurately – with mechanical tonometry in the mid 1860s. The principle behind Dond‐ ers's instrument was to displace intraocular fluid by contact with the sclera. The ophthal‐ mologist first measured the curvature of the sclera at the site of contact, and then used this measurement as a reference plane to measure the depth of indentation. Smith and Lazerat refined this technology in the 1880s, and the discovery of cocaine by Carl Koller in 1884 led the way to corneal impression tonometry soon thereafter. With the aid of a powerful corneal anesthetic agent, corneal tonometry became the definitive choice of IOP measurements be‐ cause it offered a well – defined and uniform site of impression when compared with the

Impression tonometry's major shortcoming was that it displaced so much fluid upon contact with the eye that the measured readings were highly variable and mostly inaccurate. What was needed was a way to displace a minimal amount of fluid to record IOP. This break‐ through came when Adolf Weber designed the first applanation tonometer in 1867, which gave a highly defined applanation point without indentation. After two decades of skepti‐ cism, the value of applanation tonometry was re-discovered when Alexei Maklakoff and others introduced new versions of applanationtonometers. In early 20th century, there were about 15 models of tonometers in use. In fact, Maklakoff's 1892 model is the basis of appla‐ nation tonometry today. However, digital tonometry still remained the gold standard

The first clinically useful mechanical tonometer was designed and introduced by Hjalmar‐ Schiotz in the early 1900s. The instrument was simple, easy to use, and highly precise. It was quickly accepted and became the new gold standard beginning the 1910s. Innovations in calibration led to its increased use, and a tremendous amount of knowledge about the nor‐ mal and glaucomatous eye was quickly acquired. An adjustment for ocular rigidity was in‐ troduced by Goldmann in the 1950s, which led to the development of Goldmannapplanationtonometers. The Goldmanntonometers displace such little fluid that variations in ocular rigidity are mostly negligible. The electronic and non – contact tonome‐ ters used today rely heavily on the principles and instrumentation first introduced by Ma‐

Today, for the most part, digital tonometry has been replaced by sophisticated technologies to estimate IOP. Today's instruments are incredibly accurate and easy to use. Yet, there is sometimes no good substitute for digital tonometry. For example, some ophthalmologists may prefer digital tonometry when estimating IOP in patients with keratoprostheses. In these situations, fingers that have mastered Sir William's art are highly desirable. In fact, it is said that the famous Dr. Claus Dohlman, Harvard professor of Ophthalmology at the Mas‐ sachusetts Eye and Ear Infirmary, remains as accurate in measuring IOP with his fingers as

try by an expert is a much more accurate test".[45]

286 Glaucoma - Basic and Clinical Aspects

among most ophthalmologists in the early 1900s.

any ophthalmologist using the high-tech tonometers of today!

klakoff, Schiotz and Goldmann.

sclera.

Modern diagnostic of glaucoma is unimaginable without perimetry. The merit for meas‐ urements of peripheral vision for the diagnosis and follow-up of ocular disease, as many other things in ophthalmology, is attributed to Albert von Graefe. With a primitive campimeter—a sheet of paper with radial rows of dots which served as stimuli—he was probably the first (1856) to plot paracentral field defects in chronic glaucoma and to use them in the evaluation of surgical results. Similar to von Graefe's device, Haffmanns from Donder's clinic discovered the greater frequency in glaucoma simplex of serious in‐ volvement of the upper half of the field, which gave rise to an easily detectable nasal step [46].

In 1857.Förster introduced the first perimeter, which placed accent on large targets, such as the 10/330, which permitted only very gross measurements. The observations of that time did suggest partial reversibility of field defects if the pressure was lowered substan‐ tially by an iridectomy or sclerotomy. 1889. was a very important year for a develop‐ ment of techniques most appropriate for glaucoma. Bjerrum presented 2-meter screen, the 2-meter test distance, and the 2- to 5-ram white test objects. He discovered the rela‐ tive or absolute scotomas, circling the point of fixation and including the blind spot, which became the hallmark of chronic glaucoma. Conceptually, it means the beginning of the nerve fibre bundle theory of the glaucomatous optic nerve disease.

Further major step was the occurrence of small scotomas in the zone from 12° to 20° from the point of fixation, in early glaucomas, presented by Peter [47]. These scotomas, in the be‐ ginning were not connected with the blind spot, but they reached it later via expansion.

The construction of smaller isopters, another early glaucoma characteristic, presented in 1920s, was clearly established with Bjerrum's technique. Bjerrum's technique also confirmed the regression of early glaucomatous defects following normalization of pressure document‐ ed by instrumental tonometry. The close relationship between pressure and field of vision was demonstrated further by Samojloff's observations [48]of temporary enlargement of the blind spot concurrent with osmotically induced pressure elevations. By stereocampimetry with minute targets, Evans was able to detect a gross form of parallelism between diurnal pressure fluctuations and the size of paracentralscotomas[49].

Also in 1920s was noticed that among patients with glaucomatous defects close to the point of fixation (late stages of glaucoma optic neuropathy), a surgical procedure, partic‐ ularly iridectomy, could have an untoward effect and lead to further rapid shrinkage of the visual field. The incrimination of the iridectomy referred originally to the period when the alternative, the sclerotomy, had proved relatively free of unfavourable effects on the visual field. Subsequent experience with filtering operations temporarily led to the distinction between two classes of glaucoma operations: 1) the less risky: cyclodialy‐ sis and sclerotomy and 2) the riskier: iridectomy, sclerectomy, and trephination.

#### **17. Glaucoma treatment**

The early treatment of glaucoma has its course of history (Table 1. and Table 2.).

Main discoveries where:


**Medical Treatment of Glaucoma ( 1863-1932 )**

combination with physostigmine[51].

the drug [60].

certain eyes.

**Author details**

Ivan Marjanovic

**References**

sity School of Medicine, Serbia

[ 62].

1863 Argyll Robertson and von Graefe study the effect of extracts of the calabar bean on pupil and accommodation.

The History of Detecting Glaucomatous Changes in the Optic Disc

http://dx.doi.org/10.5772/52470

289

1876 Laqueur[59] reports "a definite drop of the elevated tension after repeated installations of physostigmine in five

1876 Weber studies the mechanisms underlying the hypotensive effect of physostigmine in rabbits and in man and advises caution in its use because of the marked swelling and engorgement of the ciliary processes caused by

1877 Laqueur gives the first clear-cut account of the successful termination by use of physostigmine of attacks of

1877 Weber introduces pilocarpine with the hope that it will replace the iridectomy in some of the chronic and

1902 Darier reports significant lowering of pressure in some glaucomas, induced by adrenaline alone or in

1932 Gonioscopy furnishes the answer to the unfavorable response of certain eyes to topical adrenaline.

simple glaucomas and that it will serve to make up for the insufficient effect of the latter in many other cases

1909 Extensive clinical use of adrenaline has confirmed the beneficial results, but it has also brought to light the clearcut untoward effects, ie, the drug may cause further elevation of pressure and even precipitate acute attacks in

1923 Hamburger reintroduces adrenaline; new, more potent, more stable preparations for topical use are becoming

Glaucoma Department, University Eye Clinic Clinical centre of Serbia and Belgrade Univer‐

[1] Mackenzie W: Practical Treatise on the Diseases of the Eye. London: Longmarts, Re‐

[2] Duke-Elder S, Jay B: Introduction to Glaucoma and Hypotony. In Duke-Elder S(ed):

System of Ophthalmology. St. Louis: Mosby, 1969, Vol XI, p 337.

Von Graefe finds the miotic effect useful in that it facilitates the iridectomy.

cases of glaucoma simplex and in one case of secondary glaucoma."

1898 The hypotensive effect of topically administered adrenal extracts is discovered.

available. Untoward effects in certain eyes are rediscovered [63].

**Table 2.** A summary of the early phases of the glaucoma medical treatment.

ese, Orme Brown and Green, 1830, p 710.

acute glaucoma and of the prevention of recurrences [61].

**Surgical Treatment of Glaucoma ( 1830-1920 )**

1830 Mackenzie1 recommends scleral punctures to release vitreous and to relieve the pressure on the retina.


1915 The abexterno incision is introduced by Foroni[58].

1920 Seidel demonstrates the transconjunctival passage of aqueous after trephining procedures[16].

**Table 1.** A summary of the early phases of the glaucoma surgical treatment.


**Table 2.** A summary of the early phases of the glaucoma medical treatment.
