GONIOSCOPY DR. ZAW MIN HTET OPHTHALMOLOGIST EENT HOSPITAL MANDALAY MYANMAR

1. GONIOSCOPY
Dr. ZAW MIN HTET
Ophthalmologist
EENT Hospital
Mandalay
Myanmar
.

2. TIR
Type to enter a caption.

3. TIR
Type to enter a caption.

4. Gonioscopy
• A method of evaluating the AC angle
• can be used therapeutically for procedures such as laser trabeculoplasty
and goniotomy.
• It is a contact lens made up of a block of glass in which a mirror is
embedded at one side.

5. Principle of Gonioscopy
• Normally, the AC angle can not be visualized even with high magnification
because of TIR
• The incident light from AC angle is reflected totally into subject’s eye
because angle of incident at cornea-air interface is greater than critical
angle.
• RI of Aqueous Humor - 1.336
• RI of Cornea - 1.376
• RI of Air - 1.00

6. Principle of Gonioscopy
• When a gonioscope ( Contact Lens with higher
RI 1.52 ) is applied over the cornea
• The space between eye and lens is filled with
saline to destroy the cornea-air refracting
surface
• The light from AC angle emerges and strikes to
mirror surface that reflects the light into the
examiner’s eye.
• Therefore, AC angle is visualized by
gonioscope.

7. Principle
• Goldmann 3 mirror contact lens also has the same principle to visualize
the AC angle and peripheral retina
• Gonioscope and Goldmann 3 mirror contact lens examinations are usually
done by the use of slit lamp biomicroscope.

8. INDICATIONS
• Suspected angle closure glaucoma
• Any signs of angle closure disease (glaucoflecken, iritis, iris atrophy)
• Family History of glaucoma
• Positive Van Herick ( Shallow AC)
• High IOP
• Pigment dispersion $
• PXF

9. INDICATIONS
• Blunt trauma ( Angle recession, Cyclodialysis)
• NVI
• Ocular Inflammation
• Ocular Tumour (Ciliary body tumor, iris tumor)
• PAS
• IOFB
• Others -CCF, Sturge-Weber $,SVC obstruction, Wilson’s disease ( KF ring)
• Therapeutic -Goniotomy and Trabeculotomy, ALT

10. CONTRAINDICATIONS
• Globe Rupture
• Painful inflamed eyes
• Recurrent Corneal Erosions
• Patients with corneal abrasions
• Fresh/recent hyphen
• Ocular surface infections- HSV, Keratoconjunctivitis
• Patients with keratopathy ( bullous, band, punctate)

11. Disinfection
• Lenses must be cleaned between patients to
remove any particulate matter and the sterilized
• Soak the lens in 2% hypochlorite solution for at
least 5 minutes followed by thorough rinsing in
sterile saline, then air-drying.
Type to enter a caption.

12. Methods of Gonioscopy
A. Indirect gonioscopy
• Non-indentation
• Indentation
B. Direct gonioscopy

13. Indirect Gonioscopy
• Indirect goniolenses use a mirror to reflect rays from the angle such that
they exit the goniolens at much less than the critical angle.
• provide a mirror image of the opposite angle
• can be used only in conjunction with a slit lamp
• Gives inverted view

14. Indirect Gonioscopy
Non-indentation Goniolens
• the contact surface of the lens is steeper than the cornea & a viscous coupling
substance is required to bridge the gap between cornea and lens
• 12mm diameter - stabilize the globe and good for argon laser trabeculoplasy
1. Goldmann single mirror lens
2. Goldmann 2 mirror lens
3. Goldmann 3 mirror lens - Largest mirror at 73* (Posterior pole to equator), 2nd
largest at 67*(equator to retinal periphery), smallest (semicircular) at
59*(visualize angles)
Type to enter a
caption.
Type to enter a
caption.

15. .

16. Indentation Gonioscopy
Indentation(dynamic or compression) Gonioscopy
- a useful technique to determine the degree of PAS in a
patient with appositional angle closure
- Contact surface 9mm diameter
Goniolens
1. Zeiss
2. Posner
3. Sussman (no handle)
all of which are four-mirror gonioprisms.
Type to enter a
caption.
Type to enter a
caption.
Type to enter a caption.

17. Indentation Gonioscopy
Type to enter a caption. Type to enter a caption.

18. Advantages of Indentation Gonioscopy
• Easy to perform when mastered
• All 4 quadrants can be seen without rotation
• With slit lamp, variable magnification and illumination can be achieved
• Indentation - differentiate the appositional and synaechial angle closure
• No need coupling agent.

19. Disadvantage of Indentation Gonioscopy
• Difficult to master
• Mirror image can be confusing
• May open the angle artefactually if pressure applied

20. Direct Gonioscopy
• by constructing the viewing surface of the lens in a domed or slanted
configuration such that exiting light rays strike the contact lens/air interface
at a steeper than critical angle so that they will pass through to the observer
Type to enter a caption.

21. Direct Gonioscopy
• called ‘direct’ because light rays from the angle are viewed directly, without reflection
inside the lens
• Do not require a slit lamp
• Performed with an operating or hand-held microscope or magnifying loupes.
• in the supine position, typically under GA in the evaluation and surgical treatment of
infantile glaucoma

22. Direct Gonioscopy
Direct goniolenses
16mm (infants) &
18mm (adults)
• Koeppe
• Medical Workshop
Prismatic
• Barkan
• Swan–Jacob
Type to enter a caption.
Type to enter a caption.

24. Grading System

25. Type to enter a caption.

26. Van Herick’s Grading System

27. .
Shaffer Grading System

28. Goniscopy

29. Type to enter a caption.
Type to enter a caption.

30. Type to enter a caption.
Type to enter a caption.

31. Type to enter a caption.
Type to enter a caption.Type to enter a caption.

32. THANK YOU