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Gonioscopy
Gonioscopy is a critical clinical technique for examining the anterior chamber angle, essential for diagnosing and managing glaucoma. It involves either direct or indirect methods, using specialized lenses to overcome reflection issues inherent in standard examinations. While both techniques have advantages and disadvantages, gonioscopy serves various diagnostic and therapeutic purposes related to glaucoma and other anterior segment conditions.
In this document
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Introduction of the presenter and the topic of Gonioscopy in ophthalmology.
Overview of significant contributors to gonioscopy, including Goldmann (1938) and Barkan's involvement in glaucoma management.
Gonioscopy defined as a technique to examine the anterior chamber angle, crucial for glaucoma diagnosis and therapy planning.
Explanation of how gonioscopy addresses total internal reflection to visualize the anterior chamber angle.
List of conditions for gonioscopy, including angle closure signs, evidence of trauma, diabetes, and other ocular abnormalities.
Classification of gonioscopy into direct and indirect techniques.
Details on direct gonioscopy, including its execution and the use of various direct goniolenses.
Step-by-step process of performing direct gonioscopy and necessary positioning for optimal viewing.
Key benefits including flexibility, panoramic views, and suitability for various patient positions.
Challenges faced with direct gonioscopy like inconvenience, light reflex issues, and time consumption.
Description of indirect gonioscopy using mirrors or prisms to visualize the anterior chamber angle.
Details on various gonioprisms available for indirect gonioscopy, including advantages and limitations of each type.
Procedure for indirect gonioscopy, including patient and examiner positioning and visualization techniques.
Identifications of key anatomical structures observed in gonioscopy including Schwalbe’s line and others.
Overview of Scheie’s and Shaffer’s grading systems used for assessing angle width in gonioscopy.
Visual representations and schematic drawings of gonioscopic findings to explain utilized grading.
Diagnostic and therapeutic uses of gonioscopy in various glaucoma types and associated surgical procedures.
Challenges in performing gonioscopy during specific eye conditions and potential complications such as corneal abrasion.
Resources and references used in the presentation, along with closing acknowledgments.
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Gonioscopy
- 1. GONIOSCOPY Presented by: Simanta Borah B.ScOptom 2nd Year RCOJ
- 3. • GOLDMANN(1938): introducedthe gonioprism • BARKAN: Established the use of gonioscopy in management of glaucoma
- 4. Gonioscopy • Gonioscopy isa clinical technique that is used to examine structure in the anterior chamber angle • The assessment is essential for both diagnosing the type of glaucoma and for planning the appropriate therapy
- 5. Purpose • The angleof AC is the configuration of pathogenesis of glaucoma • Contact between the peripheral iris and the cornea signifies a closed angle, which precludes aqueous assess to the trabecular meshwork • It involves the examination of analysis of AC angle
- 6. Principle of Gonioscopy •A direct view of the angle of AC is not normally possible with the slit-lamp because of overhanging opaque scleral shelf and the fact that light which emanates from the angle is reflected back into the eye by cornea owing to phenomenon of total internal reflection • A Gonio lens is used to eliminate the total internal reflection
- 7. Indications • Closure ofthe AC angle • Historical evidence of Angle closure • Documented increased IOP • C:D greater than 0.6:1 • AC neovascularisation • Diabetes :early or established PDR • Recent or previous CRVO
- 8. Cont.. • Anisocoria • Hyphaema •Sectorial variation in AC depth • H/O or signs of penetrating ocular foreign body • Degenerative condition • Iris heterochromia • Corneal oedema • History of evidence of trauma
- 9. Types of Gonioscopy •Direct gonioscopy • Indirect gonioscopy
- 10. Direct Gonioscopy • Allowsfor direct visualization of the chamber angle • Examples of direct goniolenses include Koeppe lens Huskins Barkan lens Worth lens Swan-Jacob lens Richadrson lense Sieback lens
- 11. Cont.. • During directgonioscopy, the viewer has an erect view of the angle structures • Direct gonioscopy is most easily performed with the patient supine position and in the operating room for an exam under anaesthesia
- 12. Direct goniolenses Koeppe goniolens: -It is the most commonly used for diagnostic direct gonioscopy -It is easy to use and & provides a panoramic field of the angle
- 13. Huskins Barkan’s lens:prototype surgical goniolens used for goniotomy Worth goniolens: it anchors to cornea by partial vacuum Swan-Jacob lens: also used for surgical purpose Richadrson- Shaffers goniolens: basically a small koeppe lens used for infants Sieback goniolens: Tiny goniolens which floats on the cornea
- 14. Technique of directgonioscopy • Cornea is first anaesthetized with 4% Xylocaine instilled topically • The ideal position for direct gonioscopy is patient lying supine with examiner sitting on the side of the eye to be examined • After topical anaesthesia, goniolens is positioned on the cornea, using balanced salt solution or methyl cellulose
- 15. Cont… • Examiner holdsthe goniolens in one hand and the light source in other and scans the anterior chamber angle by shifting the examiners position until all 360 degrees have been studied
- 17. Advantages • Greater flexibilityas position of observer can be changed • Panoramic view is obtained so one part of angle could be compared with the other • Angle becomes deep in supine position so it is easy to see the angle • Can be used in sedated patient and also in infants
- 18. Cont.. • Provides astraight view rather than inverted view • Can be used for surgical procedures like goniotomy
- 19. Disadvantages • Inconvenient • Annoyinglight reflexes from cornea • Time consuming • Benefits of slit-lamp (like variable light and better clarity) are not available
- 20. Indirect gonioscopy • Usesmirrors or prisms to overcome the problem of total internal reflection • Gonioprisms have an angled mirror through which light rays from anterior chamber angle are reflected so that they emerge perpendicular to the lens-air interface
- 21. Commercially available gonioprisms 1.Gonioprisms requiring coupling agents Goldmaan 3-mirror gonioprism : -mirror is inclined at 59°
- 22. Goldmaan 1 –mirrorgonioprisms: - Mirror is inclined at 62° Goldmaan 2-mirror gonioprism: Both the mirrors are inclined at 62°
- 23. Advantages of Goldmaangonioprisms • Easy to use • Excellent view • Peripheral retina can be seen • Goldmaan 2-mirror gives best in-situ view of the angle
- 24. Disadvantages • Curvature oflens is more than that of the cornea so a coupling material is required. It blurs vision and fundus , therefore direct and indirect ophthalmoscopy can not be done immediately after its use
- 25. 2. Gonioprisms notrequiring coupling agents: a) Zeiss 4-mirror gonioprism: it has four identical mirrors angled at 64° which allow examination of the four quadrants without rotation of the lens
- 26. b)Posner gonioprism: similarto zeiss 4-mirror but is made of plastic instead of glass
- 27. c)Sussmann lens: Similar tozeiss 4-mirror d)Tokel gonioprism: Single mirror gonioprism and has got a wider field of view
- 28. Advantages of Zeiss4-mirror lens • Coupling material is not required • Easy to perform • All the four quadrants are visible at the same time so no need to rotate the gonioscope • Visualization of fundus and photography is possible
- 29. Disadvantages • May openthe angle artefactually if pressure is applied
- 30. Technique of indirectgonioscopy • The patient and the examiner must be positioned in a comfortable fashion • A drop of topical anaesthetic is then applied • The pt. is then asked to open both eyes and look upwards • The examiner can then pull down slightly on the lower lid and places the lens on the surface of the eye • The pt. is then asked to look straight ahead
- 31. Cont.. • Most examinerschoose to start with the inferior angle as it is usually a bit more open, and pigmentation of TM is slightly more prominent, allowing for easier identification of the angle structures • Continue identifying all angle structures and then repeat with the other eye
- 32. Advantages • Easier tolearn • Faster to perform • Requires less instrumentation and space • Slit-lamp provides better optics and lighting • Magnified stereoscopic view of optic disc can also be obtained
- 33. Disadvantages • Limited positioningof light rays • Difficult to perform in the horizontal meridian • Mirror image seen so confusing • Excessive pressure may open or close the angle artefactually
- 34. Gonioscopic view ofangle structures 1. Schwalbe’s line: It is a condensation of collagen tissue and notes the edge of the Descemet’s membrane
- 35. 2. Trabecular meshwork: It lies between the Schwalbe’s line anteriorly and scleral spur posteriorly and has an avg. width of 600µm Smooth in infants but becomes pigmented with age
- 36. 3. Scleral spur:made up of collagen tissue -situated just posterior to the TM 4. Ciliary Body Band: lies just behind the scleral spur. Width of CBB varies (narrow – hyperopes & wide in myopes or aphakics) 5. Roots of Iris: iris contour is slightly convex or flat
- 37. Grading system forthe angle of AC A. Scheie’s grading B. Shaffers grading
- 38. A. Scheie’s grading •It is based on the extent of visible angle structures i. Wide open- all structures visible ii. Grade-I narrow. Hadr to see over iris root into recess iii. Grade –II narrow. Ciliary body band obscured iv. Grade-III narrow. Posterior trabeculum obscured v. Grade –IV narrow . Only Schwalbe’s line visible
- 39. B. Shaffer’s grading •Estimation of the angle width is achieved by observing the angle between the imaginary lines, constructed tangential to inner surface of trabeculum and the anterior iris durface
- 41. Images of anglesin Gonioscopy
- 44. Schematic drawing ofGonioscopic findings
- 45. Clinical uses ofgonioscopy DIAGNOSTIC: • Differential between primary open angle glaucoma(POAG) and primary angle closure glaucoma(PACG) • To diagnose secondary glaucomas -Angle recession -Uveitic glaucoma • Diagnose tumors of anterior segment
- 46. THERAPEUTIC • To performargon laser trabeculoplasty • Laser iridoplasty • Laser cyclophotocoagulation • Laser sclerotomy • Goniotomy and trabeculotomy
- 47. Limitations of Gonioscopy •Can not be performed in painful inflamed eyes • Difficult to perform in cases of acute glaucoma where eyes are painful and have oedematous cornea • Hyphema • Compromised cornea • Perforated globe • COMPLICATION- Corneal abrasion
- 48. Reference • A KKhurana, Theory and Practice of Optics and Refraction, 2nd edition, page no-(305 to 313) • Eyewiki.aao.org/Gonioscopy • https://en.m.wikipedia.org/wiki/file:Gonio.pn g
- 49.