A History of Gonioscopy.7

REVIEW

A History of Gonioscopy

Wallace L. M. Alward*

ABSTRACTThe first view of the iridocorneal angle in a living human occurred accidentally in the late 1800s. Lenses were first usedto see the angle in 1914, but practical gonioscopy would not come into existence for many years as the slitlamp andlenses that could be used at the slitlamp were developed. This article reviews the history of gonioscopy.(Optom Vis Sci 2011;88:2935)

Key Words: gonioscopy, history, direct gonioscopy, indirect gonioscopy, Salzmann, Trantas, Barkan, Allen

Clinical gonioscopy is just over 100 years old. During those100 years, some remarkable scientists and astute clinicianshave played roles in the development of this importantexamination technique. This review will summarize the develop-ment of gonioscopy. The illustrations, rather than being of thepeople who advanced the field, will concentrate on the angle im-ages that they produced.

Gonioscopy is considered to have two fathers, and theprimacy of the two innovators is dependent on the views of theauthors. Dellaporta1 wrote a delightful and detailed history ofgonioscopy that includedmany charming personal anecdotes. Del-laporta focused on the contributions of Trantas, with whom heshares a Greek heritage. Other accounts focus on Salzmann, whowas the first to study the optics behind gonioscopy and the first touse a lens to view the angle. In their textbook, Gorin and Posner2

say that Salzmann will always be revered by ophthalmologists asthe father of gonioscopy. This review will consider both fatherschronologically.

Gonioscopy is required to view the iridocorneal angle, becauselight from the angle reflects back into the anterior chamber at thetear-air interface (Fig. 1). This is because of the total internalreflectionjust as in a fiberoptic cable. The only circumstances inwhich the angle can be seen without special manipulation are incases of keratoglobus where the light from the angle strikes thecornea at an angle perpendicular enough to escape. This is veryrare.

Direct Gonioscopy

To view the iridocorneal angle, one needs to overcome totalinternal reflection in some way. We do this today with a variety of

lenses, but the first gonioscopy was performed with an ophthalmo-scope and indentation. The first person to examine the iridocornealangle in a living human was the Greek ophthalmologist AlexiosTrantas3 in 1898. Trantas was in private practice. He was an out-standing observerfor example, he first identified the conjuncti-val infiltrates in vernal conjunctivitis that bear his name (Trantasdots). Trantas was able to see the angle using a direct ophthalmo-scope while indenting the sclera with his finger (Fig. 2).3 He wasactually more interested in viewing the ciliary body, ora serrata,and anterior retina. His view of the iridocorneal angle was a fortu-nate accident. In 1900, he described the appearance of a cyclodi-alysis cleft in a patient with an iridodialysis (his view was madeeasier by the iridodialysis, because the iris was not in the way).1 Helater presented remarkably detailed drawings of the angle (Fig. 3).4

His descriptions of the angle were an afterthought, included in anappendix of an article describing the retrociliary region.4 It wasTrantas who coined the term gonioscopy, meaning observationof the angle, in his native Greek.1

Maximilian Salzmann was a brilliant ophthalmologist who,upon graduating from college at age 15, went on to contribute inall aspects of eye research. He was also skilled in languages, math-ematics, geology, and botany. Salzmann was a gifted painter whosepaintings were used in many textbooks of his time.5 His owntextbook, The Anatomy and Histology of the Human Eyeball in theNormal State, was a classic in German and was translated intoEnglish. Salzmann was unaware of the work of Trantas, becausethe descriptions of gonioscopy in the articles of Trantas did notappear in the titles or abstracts.1 He first recognized the concept oftotal internal reflection.6 He also determined that total internalreflection could be overcome with a highly convex lens (Fig. 4).Salzmannwas the first to view the angle through a contact lens and,in 1915, published an article with excellent drawings of the angleobtained by means of a Fick contact lens (a lens designed to treatkeratoconus).7 He was not satisfied with the view through the Fick

*MDDepartment of Ophthalmology, University of Iowa Carver College of Medi-

cine, Iowa City, Iowa.

1040-5488/11/8801-0029/0 VOL. 88, NO. 1, PP. 2935OPTOMETRY AND VISION SCIENCECopyright 2011 American Academy of Optometry

Optometry and Vision Science, Vol. 88, No. 1, January 2011

lens and, so, had Zeiss build him a lens with a smaller radius ofcurvature.2 Although Trantas was the first to see the angle, Salz-mann was the first to really study the angle. Salzmann stressed theimportance of gonioscopic examination in the fellow eye of pa-tients who had suffered an attack of acute glaucoma.2 He recog-nized that the development of synechiae in the angle did not alwayslead to increased intraocular pressure.2 Salzmann was also the first

to describe blood in Schlemms canal.1 Salzmann produced won-derful drawings of the iridocorneal angle (Figs. 5 and 6).6,7

Through the courtesy of S. Karger AG, Basel, all of Salzmannsgonioscopy paintings are reproduced at: http://gonioscopy.org/salzmann/salzmann.html.

Mizuo examined the inferior angle in patients by everting thelower lid and filling the cul-de-sac with saline. The saline meniscusacted like a contact lens.8 He described this technique in 1914.Elschnig had verbally reported to Salzmann the same techniqueusing the patients own tears.2,7 The technique was difficult toperform because the saline lens was lost whenever the patientblinked.8

Many events occurred around 1920 that brought gonioscopyinto clinical relevance. Zeiss developed the modern slitlamp atabout this time, which permitted significant advances in gonios-copy. In 1920, Curran9 published his landmark article that recog-nized that angle-closure glaucoma was caused by forward bulgingof the iris and that surgical iridectomy (which had been used in-discriminately for glaucoma) would only work for angle closurecases. He recognized that the iridectomy worked by reestablishingflow from the posterior to anterior chambers, not by uncoveringthe trabecular meshwork. In 1919, Koeppe10 used the Zeiss slit-lamp to examine the angle with his newly developed direct contactlens, which was thicker and more convex than the lenses used by

FIGURE 1.Total internal reflection occurs when the light from the iridocorneal anglestrikes the tear-air interface at a shallow enough angle that all the light isreflected back into the eye. Reproduced with permission from Color Atlasof Gonioscopy, 2nd ed: San Francisco, American Academy of Ophthal-mology, 2008.24

FIGURE 2.One can overcome total internal reflection by indenting the limbus tomake the light from the angle exit the cornea at a steep enough angle thatit is not reflected back into the eye. This is the technique that was used byTrantas. Reproduced with permission from Color Atlas of Gonioscopy,2nd ed: San Francisco, American Academy of Ophthalmology, 2008.24

FIGURE 3.Trantas made the first drawings of the iridocorneal angle. This showsremarkable detail given the limitations of his technique. Published in1918.1,4

FIGURE 4.Direct lens. This lens changes the approach of the light from the iridocor-neal angle so that it is more perpendicular, thus overcoming total internalreflection. Reproduced with permission from Color Atlas of Gonioscopy,2nd ed: San Francisco, American Academy of Ophthalmology, 2008.24

FIGURE 5.Painting by Salzmann, 1915. Right eye, inferior and temporal-temporalportion, male, 37 y/o, traumatic cataract, (case VII) (goniolens). Circum-scribed and incomplete peripheral synechiae, pigmentation of the trabec-ular meshwork. Reproduced with permission from Z Augenheilkd, 34,2649, 1915.31

30 A History of GonioscopyAlward


Salzmann. Gonioscopy was performed with the patient seated atthe slitlamp. A knotted bandage rested on a central depression inthe lens to secure it to the patient. This technique was effective onlyfor evaluating the nasal and temporal portions of the angle. TheKoeppe lens and modifications of the Koeppe lens (Barkan, Swan-Jacobs, etc.) are still used today for direct gonioscopy.

In 1925, Manuel Uribe Troncoso11 developed a selfilluminat-ing monocular gonioscope that permitted examination of all partsof the angle. The handheld device combined the examining ocularswith an illumination system. He also improved on the Koeppe lensby using polymethylmethacrylate instead of glass.2 In 1942, hecreated a handheld stereoscopic gonioscope.

In 1927, Thorburn first photographed the angle in a case ofangle closure brought on by mydriatics and subsequently reversedby physostigmine. He also observed that the majority of his pa-tients with glaucoma had open angles.12

Barkan et al.13 used a binocular slitlamp suspended from theceiling and a handheld illuminator to view the angle through aKoeppe lens. His technique had the advantage of bright illumina-tion and sufficient magnification. The flexibility of the ceiling-mounted handheld slitlamp enabled the entirety of the angle to beevaluated with the Koeppe lens in a supine patient. Barkans appa-ratus brought gonioscopy into practical clinical application.

Barkan14,15 was also the first to describe goniotomy under directvisualization for primary congenital glaucoma. Before Barkan, go-

niotomy had been performed without visualizing the angle. Hedeveloped a special variation of the Koeppe lens in which one sidewas flattened to permit passage of the knife through the temporalcornea. Barkan felt that the eyes of children with congenital glau-coma had a membrane covering the iridocorneal angle (Barkansmembrane) because of the glistening appearance of the angles ofbabies with glaucoma.16 It is now recognized that there is no Bar-kans membrane, simply compressed trabecular beams.17

Clinical use of direct gonioscopy is now limited to the operatingroom for examining babies under general anesthesia and for per-forming angle surgery. Direct gonioscopy is required for somesurgical techniques such as for goniotomy for infantile glaucomaangle and for the Trabectome for open-angle glaucoma. Directgonioscopy is rarely used in the clinic because it is inconvenient.The patient needs to be supine in a special room with a ceiling-mounted counterbalanced slitlamp. Any examination techniquethat is inconvenient is less likely to be performed. The Van Herickestimation of angle depth was developed because it was not prac-tical to perform direct gonioscopy on every patient, and it washelpful to have a means of identifying worrisomely narrow anglesat the slitlamp. To quote Van Herick et al.,18 In the routineexamination of nonglaucomatous patients, it is impractical to per-form gonioscopy; it is only done of the angles are thought to benarrow. In 2010, indirect gonioscopy is easy and convenientenough that the Van Herick technique should simply be an ad-junct to gonioscopy.

Indirect Gonioscopy

Modern indirect gonioscopy was introduced in 1938 with theGoldmann mirrored contact lens.19 The Goldmann lens uses a

FIGURE 7.Indirect gonioscopy lens. Light from the iridocorneal angle is reflected bya mirror so that it is visible to an observer at a slitlamp. Reproduced withpermission from Color Atlas of Gonioscopy, 2nd ed: San Francisco,American Academy of Ophthalmology, 2008.24

FIGURE 6.Painting by Salzmann 1915. Left eye, temporal quadrant, male, 37 y/o,small rupture of the corneoscleral border (case XIV). Displacement of theiris because of the vitreous coming forward and radial tear. Visible coronaciliaris (pars plicata). Reproduced with permission from Z Augenheilkd,34, 2649, 1915.

A History of GonioscopyAlward 31


mirror to redirect the light from the iridocorneal angle, so that it isvisible to the examiner viewing through a slitlamp (Fig. 7). Gold-mann was another polymath whose name is familiar because of thegonioscopy lens, tonometer, and perimeter that bear his name. Hiscontributions to the understanding of the eye in health and diseasewere too numerous to list here.20 With the Goldmann lens at aslitlamp, one could readily examine the entire angle using thereadily available slitlamp, rather than a separate apparatus. Gonios-copy was no longer reserved for those with suspiciously narrowangles on slitlamp examination. The Allen lens, developed a fewyears later, used totally refractive prisms rather than a mirror.21

This was later modified into the Allen-Thorpe gonioprism, whichhad four prisms and permitted most of the angle to be viewedwithout rotation of the lens (Fig. 8).22 The Allen-Thorpe lens hadflanges that held it in place allowing the examiner time and free

hands to make detailed drawings of the findings. Four-mirroredlenses, such as the Zeiss, Posner, Sussman, andVolkG-4 lenses, arecommonly used today.Unlike theGoldmann lens, these lenses do notrequire a methylcellulose coupling solution. The remarkable anglepaintings of Lee Allen were created with the Allen-Thorpe lens (Figs.9 and 10).Many of the Lee Allens paintings are included in theColorAtlas of Gonioscopy,23,24 and all of his gonioscopy paintings are avail-able at: http://gonioscopy.org/leeAllenPaintings.html.

There have been no major developments in lens design over thelast several decades. There have been modifications to the Gold-mann and Allen-Thorpe/Zeiss lenses. Variations of the Goldmannlens include lenses with one to four mirrors. In the three-mirrorlens, two of the mirrors are for viewing the peripheral retina. Other

FIGURE 8.Allen-Thorpe lens. This was the original four-mirror lens. It actually usedprisms instead of mirrors and had a flange to hold it into place. The prismswere replaced by mirrors in subsequent lenses (Zeiss, Posner, etc.).

FIGURE 9.A Lee Allen painting and sketch of a normal iridocorneal angle with deep trabecular pigmentation. Reproduced with permission from the Universityof Iowa.

FIGURE 10.A Lee Allen painting showing blood in Schlemms canal. Reproduced withpermission from the University of Iowa.



Goldmann-style lenses (such as the Ritch lens) are specially de-signed and coated with antireflective material for the delivery oflaser energy. Others have mirrors that magnify slightly. The Zeissstyle lenses are now available in plastic or glass withmirrors that areless fragile than the original Zeiss lens. These are available withhandles (e.g., Posner and Volk G-4 with optional handle) or with-out handles (e.g., Sussman and Volk G-4), and there is even asix-mirror version (Volk G-6). However, the recent changes ingonioscopy lenses have been evolutionary, not revolutionary.

A major advance in gonioscopy technique was the introductionof the technique of indentation gonioscopy. First taught by Drs.Becker andMoses atWashingtonUniversity with a handheld Zeissgoniolens, it was refined by using the Zeiss lens on anUnger handlebyMax Forbes in 1966.25 Indentation gonioscopy requires the useof a gonioscopy lens with an area of contact smaller than the cornea(e.g., Zeiss, Posner, Sussman, Volk G-4, etc.). By using one of

these lenses, the examiner pushes against the cornea, which drivesthe lens-iris diaphragm posteriorly. This permits the examiner todetermine whether areas of angle closure are because of appositionor synechiae. Indentation gonioscopy can also reveal a peripheraliris hump in plateau iris syndrome. Lenses with large areas ofcontact (such as the Goldmann lens) are not ideal for this.

Grading Systems

The first system to grade the angle was that of Gradle andSugar26 in 1940. They used an Ulbrich drum mounted on theslitlamp to measure the chamber depth in millimetersnot some-thing that could be practically used in the clinic. Scheie27 devel-oped a grading system based on the visible structures. The Scheiesystem was opposite of our current systems. In the Scheie system,there was a category called Wide followed by grade I, which was

FIGURE 11.An illustration by Emil Bethke from Troncosos textbook. Reproduced with permission from Gonioscopy: Philadelphia, FA Davis, 1947.32

TABLE 1.Important textbooks and atlases of gonioscopy

Year Authors Title Publisher

1947 Troncoso Gonioscopy FA Davis1955 Van Beuningen Atlas der Spaltlampengonioskopie Thieme1957 Gorin and Posner Slit Lamp Gonioscopy Williams & Wilkins1962 Shaffer Stereoscopic Manual of Gonioscopy CV Mosby1973 Kimura Color Atlas of Gonioscopy Igaku Shoin1994 Alward Color Atlas of Gonioscopy CV Mosby2008 Alward and Longmuir Color Atlas of Gonioscopy, 2nd ed. American Academy of Ophthalmology



slightly narrowed through grade IV, which was completely closed.Today, some still use a system in which they describe the visiblestructure such as open to the ciliary body face etc. Importantly,Scheie introduced a scale of grading the pigmentation of the pos-terior trabecular meshwork (from none to grade IV) that is usedtoday.

The most widely used systems nowadays are the Shaffer andSpaeth systems. The Shaffer28 grading technique was described inhis 1962 textbook. Shaffer determined an angle width in degrees(e.g., grade 110 and grade 4 3545). It has the advantage ofbeing widely recognized and easy to understand. A disadvantage isthat it provides only angular width information and tells nothingabout the iris shape or the level at which the iris inserts.

Spaeth29 modified the Shaffer system to provide informationregarding the level of iris insertion (on a scale of A to E, with Abeing anterior to Schwalbes line and E being extremely deep intothe ciliary body), the angle of iris approach (in degrees), and theconfiguration of the iris (b for bowed forward, f for flat, c forconcave, and p for plateau). To this, one adds the angle pigmen-tation. For example, the Spaeth system would grade the angle inthe Lee Allen painting in Fig. 9 to beD45f, with 2 pigmentation.The Spaeth system also permits information on indentation go-nioscopy findings. This system is somewhat harder to learn butprovides much more information than any other alphanumericgrading system.

Textbooks of Gonioscopy

In 1947, Troncoso published a comprehensive 306-page text-book entitled Gonioscopy. The text contains comparative anatomyand gonioscopy as well as beautifully illustrated descriptions of theangle in health and disease. Many of the illustrations were paintedby Emil G. Bethke (Fig. 11). Interestingly, Bethke had been amedical illustrator at the University of Iowa where he roomed witha fellow artist, E. Lee Allen. When Bethke left the University, LeeAllen became the artist for the Department of Ophthalmology anddeveloped a life-long interest in gonioscopy (see Figs. 8 to 10).Since Troncosos book, there have been a handful of gonioscopytexts and atlases; the most important of which are included inTable 1.

Shaffers Stereoscopic Manual of Gonioscopy is a wonderful re-source, now out of print.28 His book includes beautiful drawingsby Joan Esperson and three-dimensional photographs viewedthrough a View-Master. Kimuras Color Atlas of Gonioscopy hasbeautiful photographs of the angle.30 Kimuras atlas was out ofprint when my book of the same name was published in 1994.23

Because gonioscopy is a dynamic examination, it may be besttaught with video, instead of still images. I created a webpage toteach gonioscopy (www.gonioscopy.org). The site is free and is notindustry supported. It includes detailed descriptions of basic andadvanced examination techniques as well as hundreds of videoexamples of pathology.

There are new ways to evaluate the iridocorneal angle, such asultrasound biomicroscopy and optical coherence tomography. Thesetechniques can describe the width of the angle and perhaps the riskof developing angle closure. They are excellent tools, but theycannot replace gonioscopy, which tells us so much more thanwhether the angle is open or closed. We are fortunatethrough

the efforts of Trantas, Salzmann, Zeiss, Barkan, Goldmann, Allen,and othersto be able to actually look at the dysfunctional mesh-work rather than having to rely on imaging.

Received April 26, 2010; accepted August 11, 2010.

REFERENCES

1. Dellaporta A. Historical notes on gonioscopy. Surv Ophthalmol1975;20:13749.

2. Gorin G, Posner A. Slit Lamp Gonioscopy, 3rd ed. Baltimore, MD:Williams & Wilkins; 1967.

3. Trantas A. Ophtalmoscopie de la region ciliaire et retrociliaire. ArchOphtalmol (Paris) 1907;27:581606.

4. Trantas A. Lophtalmoscopie de langle irido-corneen. Arch Ophtal-mol (Paris) 1918;36:25776.

5. Sugar HS, Foster CC. Maximilian Salzmann. Ophthalmic pioneerand artist. Surv Ophthalmol 1981;26:2830.

6. Salzmann M. Die Ophthalmoskopie der Kammberbucht. Z Augen-heilk 1914;31:119.

7. Salzmann M. Nachtrag zu ophthalmoskopie der kammerbucht. ZAugenheilk 1915;34:1602.

8. Mizuo. Ein Verfahren zur Besichtigung der Kammberbucht. KlinMonatsbl Augenheilkd 1914;52:561.

9. Curran EJ. A new operation for glaucoma involving a new principlein the etiology and treatment of chronic primary glaucoma. ArchOphthalmol 1920;49:13155.

10. Koeppe L. Diemikroskopie des lebenden Kammerwinkels im fokalenLichte der Gullstrandschen Nernstspaltlampe. Albrecht von GraefesArch Klin Ophthalmol 1919;101:4866.

11. TroncosoMU. Gonioscopy with the Electric Ophthalmoscope. NewYork, NY: New York Academy of Medicine; 1921.

12. Thorburn T. A gonioscopical study of anterior peripheral synechiaein primary glaucoma. Svenska Lakaresallskapets Handligar 1927;53:25291.

13. Barkan O, Boyle SF, Maisler S. On the genesis of glaucoma. Animproved method based on slit lamp microscopy of the angle of theanterior chamber. Am J Ophthalmol 1936;19:20915.

14. Barkan O. Glaucoma: classification, causes, and surgical control. Re-sults of microgonioscopic research. Am J Ophthalmol 1938;21:1099117.

15. Barkan O. Recent advances in the surgery of chronic glaucoma. Am JOphthalmol 1937;20:123745.

16. Barkan O. Pathogenesis of congenital glaucoma: gonioscopic andanatomic observation of the angle of the anterior chamber in thenormal eye and in congenital glaucoma. Am J Ophthalmol 1955;40:111.

17. Anderson DR. The development of the trabecular meshwork and itsabnormality in primary infantile glaucoma. Trans Am OphthalmolSoc 1981;79:45885.

18. VanHerickW, Shaffer RN, Schwartz A. Estimation of width of angleof anterior chamber. Incidence and significance of the narrow angle.Am J Ophthalmol 1969;68:6269.

19. Goldmann H. Zur Technik der Spaltlampenmikroskopie. Ophthal-mologica 1938;96:907.

20. Fankhauser F. Hans Goldmann. Ophthalmic Surg 1994;25:812.21. Allen L, OBrien CS. Gonioscopy simplified by a contact prism. Arch

Ophthalmol 1945;34:4134.22. Allen L, Braley AE, Thorpe HE. An improved gonioscopic contact

prism. AMA Arch Ophthalmol 1954;51:4515.23. Alward WL. Color Atlas of Gonioscopy. London: Wolfe; 1994.24. Alward WL, Longmuir RA. Color Atlas of Gonioscopy, 2nd ed. San

Francisco, CA: American Academy of Ophthalmology; 2008.



25. Forbes M. Gonioscopy with corneal indentation. A method for dis-tinguishing between appositional closure and synechial closure. ArchOphthalmol 1966;76:48892.

26. Gradle HS, Sugar HS. Concerning the anterior chamber angle. III. Aclinical method of goniometry. Am J Ophthalmol 1940;23:11359.

27. Scheie HG. Width and pigmentation of the angle of the anteriorchamber; a system of grading by gonioscopy. AMAArchOphthalmol1957;58:5102.

28. Shaffer RN. Stereoscopic Manual of Gonioscopy. St. Louis, MO:Mosby; 1962.

29. Spaeth GL. The normal development of the human anterior chamberangle: a new system of grading. Trans Ophthalmol Soc UK 1971;91:70939.

30. Kimura R. Color Atlas of Gonioscopy. Tokyo: Igaku Shorin Ltd.;1974.

31. Salzmann M. Die Ophthalmoskopie der Kammerbucht. Z Augen-heilkd 1915;34:2649.

32. Troncoso MU. Gonioscopy. Philadelphia, PA: FA Davis; 1947.

Wallace L. M. AlwardDepartment of Ophthalmology

University of Iowa Carver College of Medicine200 Hawkins Drive

Iowa City, Iowa 52242e-mail: [email protected]



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A History of Gonioscopy.7