The term “gonioscopy” is derived from the Greek words go–'ne– (angle) and ˘os'k-pe– (view). It is a clinical biomicroscopic technique of examining the angle of the anterior chamber of the eye with the use of a special contact lens known as the gonioscope.
It was Alexios Trantas in 1907 (Table 1.1), who first visualized the angle in a living eye, in a case of keratoglobus by indenting the limbus. In his paper, he described the angle of the anterior chamber as seen with and without digital pressure with a direct ophthalmoscope using positive lens powers.1 Trantas also coined the term gonioscopy. The Goniolens was introduced by Maximilian Salzmann in 19142 wherein he used a scleral contact lens with a corneal radius of 7–8 mm. Salzmann described a variety of normal and pathologic findings in the angle including peripheral anterior synechiae and angle recession. He is called “the father of gonioscopy”.
Curran, in 1920, observed that shallowing of the anterior chamber was due to forward bulging of the iris caused by accumulation of aqueous behind the iris.3 Thorburn, a 4Swedish clinician, did extensive work in peripheral anterior synechiae and angle closure and was the first to photograph the angle in 1927.4 He observed that intraocular pressure rises with atropine instillation and decreases with miotics. He thus hypothesized that the peripheral iris may be blocking aqueous egress. Manuel Troncoso clarified the anatomic terminology of the structures of the angle and their identification on gonioscopy.5 In 1936, Otto Barkan made an important contribution through his gonioscopic classification of glaucomas into open angle and closed angle glaucomas and he was the first to find a true clinical implication of gonioscopy by performing goniotomy in case of congenital glaucoma. He coined the term “open angle glaucoma” and suggested that sclerosis of the trabecular meshwork was the cause of raised intraocular pressure.6 The gonioprism was described by Goldmann in 1938.
Gradle and Sugar were the first ones to try and quantitate the angle configuration in 1940, a goal not yet reached. In 1956, Shaffer and Tour described various gonioscopy techniques which hold good to date.7 Scheie8 proposed a classification for angle grading by gonioscopy in 1957. Forbes in 1966 gave the description of pressure gonioscopy with the Zeiss 4 mirror lens. Spaeth, in 1971 developed a new classification of the angle structures.9 In 1979, Sussman introduced the Sussman goniolens which was a directly held four mirror goniolens.10 Ritch in 1985 developed the Ritch trabeculoplasty lens which is useful for diagnostic gonioscopy as well as for trabeculoplasty and iridotomy.11 The “trabeculens” was developed by Mizuno which was a further modification of the Ritch lens.12 Congdon in 1999 developed biometric gonioscopy which is a technique of objective measurement of the anterior chamber angle using a slit lamp mounted reticule.13
REFERENCES
- Trantas A. L'ophthalmoscopie de l'angle iridocorneen (gonioscopie). Conclusions a entirer pour la nature du canal de Schlemm Arch Ophthalmol (Paris) 1918; 36: 257.
- Salzmann M. Die Ophthalmoskopie der Kammerbucht. Z Augenheilk 1914; 31: 1.
- Curran EJ. A new operation for glaucoma involving a new principle in the etiology and treatment of chronic primary glaucoma. Arch Ophthalmol 1920; 49: 131.
- Thorburn T. A gonioscopical study of anterior peripheral synechiae in primary glaucoma. Arch Ophthal 1933; 10: 615–20.
- Troncoso MU. Treatise on Gonioscopy. Philadelphia FA Davis 1947.
- Barkan O, Boyle SF, Maisler S., On the genesis of glaucoma. An improved method based on slit lamp microscopy of the angle of the anterior chamber. Am J Ophthalmol 1936; 19: 209–15.
- Shaffer RN, Tour RL., A comparative study of gonioscopic methods. Am J Ophthalmol 1956; 41: 256–265.
- Scheie HG. Width and pigmentation of the angle of the anterior chamber. A system of grading by gonioscopy. Arch Ophthalmol 1957; 58: 510.
- Spaeth GL. The normal development of the human anterior chamber angle: a new system of descriptive grading. Trans Ophthalmol Soc UK 1971; XCI: 709.
- Sussman W. A new instrument for gonioscopy. Ophthalmology 1979; 86: 130.
- Ritch R. A new lens for argon laser trabeculoplasty. Ophthalmic Surg 1985; 16: 331.
- Mizuno K. A new multipurpose goniolens. Arch Ophthalmol 1988; 106: 1309.
- Congdon NG, Spaeth GL, Augsburger J, et al. A proposed simple method for measurement in the anterior chamber angle: Biometric Gonioscopy. Ophthalmol 1999; 106: 2161–2167.