Gonioscopy

1. Dr. Reshma Peter
GONIOSCOPY

2. INTRODUCTION
Gonioscopy
allows visualization of
the anterior chamber angle by using
direct or indirect contact lenses to overcome the
Total Internal Reflection
 Enables glaucomas to be classified by assessing
whether the angle is open or closed
 Various Pathologies involving angle structures can
be observed

3. HISTORICAL ASPECTS
 Trantas (1907)
• 1st visualized the anterior chamber angle in a patient with
keratoglobus by indenting the limbus
• coined the term gonioscopy.
 Salzmann (1914)
• Established that visualization of the angle was impossible without
optical instrumentation due to phemomenon of Total internal reflection
• Thus introduced the goniolens
 Koeppe (1919)
• designed an improved steeper lens.
•
 Troncoso
• developed gonioscope for magnification and illumination of
the angle.
 Goldmann (1938)
• introduced the gonioprism
 Barkan
• established the use of gonioscopy in the management of glaucoma

4. Anatomy Of the Angle

8. ANGLE STRUCTURES

9. PRINCIPLES AND OPTICS
• Critical angle for the cornea-air interface is approximately
46 degrees.
•Total internal reflection prevents direct visualization of ang
le in nearly all eyes.
•The incident angle of light- reflected from angle is greater
than the critical angle at the cornea–air interface.

10. L i < L r
light rays are refracted at the contact l
ens-air interface
light rays are reflected by a mirror
light rays leave the lens at nearly right
angles at the contact lens-air interface
Total internal reflection is overcome by eliminate the cornea-air interface
by
Goniolenses in DIRECT method contact lenses –-to examine the
anatomy of the angle
Gonioprisms/mirror and viscous coupling solution or tears in
INDIRECT method
As the index of refraction of a contact lens approaches that of the corne
a, there is minimal refraction at the interface of these two media, which
eliminates the optical effect of the front corneal surface.
Thus light rays from the anterior chamber angle enter the contact lens a
nd are then made to pass through the new contact lens-air interface

11. METHODS
• Three primary methods:
• Indirect gonioscopy: Using mirrors,the
angle is examined with reflected light
• Indentation (dynamic) gonioscopy
• Direct gonioscopy: look directly at the
angle with lenses.

12. GONIOPRISMS(Indirect)
GONIOLENSES(Direct)
Requiring coupling agents Not requiring coupling agents
1.Goldmann single mirror
gonioprism
2.Goldmann 2 mirror gonioprism
3.Goldmann 3 mirror gonioprism
4.Allen Thorpe gonioprism
1.Zeiss 4- mirror Gonioprism
2.Posner Gonioprism
3.Sussman lens
4.Tokel Gonioprism
5.Ritch Trabeculoplasty laser lens
1.Koeppe Goniolens
2.Huskins Barkans lens
3.Thorpe Goniolens
4.Swan Jacob ‘s lens
5.Richardson Shaffer’s Goniolens
6.Worth goniolens
7.Sieback goniolens

13. GONIOPRISMS
Requiring coupling agents
1.Goldmann single mirror gonioprism
Prototype diagnostic gonioprism
• Mirror inclined at 62 degrees from plano front
surface
• Needs to be rotated 3times to examine the whole
angle
• Mirror Height -12 mm
• Central well diameter -12 mm
• Posterior Radius of curvature -7.38 mm

14. 2.Goldmann two mirror gonioprism
• Both mirrors inclined at 62 degrees
• Needs to be rotated once to examine whole
angle
3.Goldmann three mirror gonioprism

15. 1.Gonioscopy mirror:
• Smallest
• Dome shaped upper border
• Inclination of 59 degrees
Broad area of contact with cornea (12 mm)
may artificially close the angle under pressure
2.Equatorial mirror:
• Largest
• Oblong shaped
• Inclined at 67 degrees
• Examine Pars plana of ciliary body
Posterior pole to the equator
3.Peripheral mirror:
• Intermediate size
• Square shaped
• Inclined at 73 degrees
• Examine from equator to ora serrata

16. 4.Allen Thorpe gonioprism
• 4 prisms instead of mirrors
• Allows examination of whole angle without rotating the
prisms
• Suspended by a frame

17. Advantages of Goldmann gonioprisms
• Easy to use
• Excellent view
• Peripheral retina can be seen
• Stabilizes the globe
Can be used in Argon Laser trabeculoplasty

18. Disadvantages of Goldmann gonioprisms
• Only 1 mirror for gonio-has to be rotated by 360
degrees
• Cannot be used for indentation
• In case of 3 mirror lens, broad area of contact with
cornea may cause artefactual closure of angle
Curvature of lens > cornea
Coupling material required
Blurs vision and fundus
Field charting ,direct and indirect ophthalmosc
opy
cant be done immediately after use

19. GONIOPRISMS
Not requiring coupling agents
1.Zeiss 4- mirror Gonioprism
• 4 identical mirrors angled at 64 degrees
• On an UNGER HOLDER
• Small area of contact with the cornea (9mm)
Indentation gonioscopy can be performed

20. Zeiss 4- mirror Gonioprism
ADVANTAGES DISADVANTAGES
• Easy to perform
• All 4 quadrants visible at sa
me time
• Rotation of 11 degrees
covers area between the
mirrors
• Indentation gonio
• Coupling material not
required,
thus fundus viewing and
photography possible
• Difficult to master
• Does not stabilise the
globe
• May open the angle
artefactually If
pressure is applied

21. 2.Posner Gonioprism
• Similar to Zeiss
• Made of plastic instead of glass
• Has a fixed handle

22. 3.Sussman lens
Similar to Zeiss
but has no handle
4.Tokel Gonioprism
• Single mirror lens
• Broader viewing area
than Goldmann single mirror lens
• Convex anterior face that provides slight
magnification
• For delivery of Laser to angle

23. 5.Ritch Trabeculoplasty laser lens
• 2 mirrors tilted at 59degrees to see inferior angle
• 2 mirrors at 64 degrees to view the superior angle
• A convex button in front of a 59 degree mirror and a
64 degree mirror for extra magnification and laser
treatment

24. GONIOLENSES
Koeppe lens
• Prototype diagnostic lens
• Available in several sizes
• Most commonly used lens
for diagnostic direct gonio.
Huskins Barkan
lens
• Prototype surgical goniolens
• Used for Goniotomy
Thorpe Goniolens
Surgical and diagnostic lens for operating rooms

25. Swan jacob’s
lens
• Surgical goniolens
• used in children
Richardson Shaffer’s lens
Small lens for use in infants
Worth goniolens
It anchors to the cornea by partial vaccum
Sieback goniolens
Tiny goniolens which floats on the cornea

26. DIRECT GONIOSCOPY
• Patient in Supine position
• 4 %Xylocaine as topical anaesthesia
• Saline bridge the gap between lens and cornea
• Koeppe lens – 50 D convex lens
• External Hand held binocular microscope
• External Barker focal illuminator with other hand
• Possible simultaneous comparison of both eyes
• Image is direct and upright.

27. TOTAL MAGNIFICATION
MAGNIFICATION DUE
TO KOEPPE LENS
MAGNIFICATION DUE TO
MICROSCOPE
x 1.5 x 16
X 24

28. • Offers a panoramic, less magnified view than
indirect gonioscopy.
• Less likely to exert pressure upon the cornea or
limbus, causing errors

29. Advantages of Direct
Gonioscopy
 The height of the observer may be changed to
look deeper into a narrow angle, whereas the
gonioprism is limited by the height of the mirror
 Angle becomes deeper in supine position –
easier to see angle
 Provides a straight-on view of the angle rather
than the mirror image given by the indirect
lenses.
 Panoramic view, so 1 part of angle can be com
pared to other

30.  Goniolens may cause less distortion of the ante
rior chamber
 Using 2 lenses,both eyes can be
simultaneously examined
 Possible to vary the angle of visualization
more easily. Therefore, a narrow angle can be
assessed to see if it is a steep approach to an
open angle or a completely closed angle.
 Can be used for surgical procedures like gonioto
my and goniosynechialysis
 Can be used in sedated or anesthetized patient
s, as in the examination of children

31. Disdvantages of Direct
Gonioscopy
 Inconvenient
 Annoying light reflexes from the cornea
 Timeconsuming
 Benefits of slit lamp not available

32. INDIRECT GONIOSCOPY
PROCEDURE
 Dim illumination
 Eye anaesthetised with topical agent
 Appropriate positioning of the patient at slit lamp

33. The concave face of Goldmann lens should be filled with a Methyl
cellulose coupling fluid before its applied to the eye.
Care should be taken to keep air bubbles out of the solution

34.  Patient is asked to look down
 Thumb used to retract the upper eyelid
 Lower edge of gonioscope placed on inferior sclera
 Gonioscope tipped on to the cornea in 1 smooth
maneouvre

36. Slit lamp gonioscopy
• The part that is viewed is 180 degrees away from
the mirror that is being used.
• Slit lamp beam is focussed on the mirror that
shows the angle diametrically opposite to it.
• Image is inverted but not laterally reversed
• Illumination and height of slitlamp
are reduced so that it doesn’t
impinge on the pupil and cause
pupillary constriction and
Artefactual opening of angle.

37. • With a narrow, short slit beam off axis, the quadrant o
f the angle to be assessed is first examined with the f
our-mirror lens, with
 no pressure on the cornea
 the patient looking sufficiently far in the direction of the
mirror that the examiner can see as deeply into the angl
e as possible.
• The inferior portion of the angle is typically the
widest and where the trabecular meshwork has the
most pigment, thus easiest to identify
structures and familiarize with patient ‘s anatomy
• Thus most clinicians apply lens so that mirror is at the
top of the eye, to allow inferior angle to be examined
first.
• Then the goniolens is rotated to view other portions
of the angle

38. Illumination methods
Diffuse illumination Focal illumination with a
broad beam

39. Focal illumination with a narrow beam

40. • Using a narrow slit beam at an oblique angle
• 2 linear reflections identified from
 external surface of cornea and its junction with sclera
 Internal surface of cornea
• They meet at Schwalbe s line.
• Slit of light appears above Schwalbe ‘s line as a 3D parallelepiped
of light.
• Used for identifying landmarks in patients with
 Closed angles
 Open angles with no trabecular meshwork pigmentation

42. Advantages of Indirect
Gonioscopy
• Easier to learn
• Faster to perform, particularly with the Zeiss
four-mirror lenses and modified Goldmann-type
lenses, because no viscous bridge is required.
• Slitlamp provides better optics, variable
magnification and illumination
• Requires fewer additional instruments and
occupies less space than direct gonioscopy.
• Gonioprisms with a posterior radius of curvature closer
to that of the anterior corneal surface may also reduce
Corneal distortion.

43. • Gonioprisms with taller mirrors facilitate
visualization of narrow angles.
• The slit beam can create a corneal wedge to help to
define the structures of the angle.
• Because of its relatively small diameter of
corneal contact, the Zeiss four-mirror lens
can also be used in compressive gonioscopy.
• Indentation gonioscopy can be performed with the
Posner or Sussmann lens to distinguish
appositional from synechial angle closure.
• Magnified stereoscopic view of the optic disc can be
obtained

44. Disadvantages of Indirect
Gonioscopy
• Limited positioning of light rays
• Comparison not possible
• Difficult to perform in horizontal meridian
• Inverted Mirror image seen – confusing
• Excess pressure over the cornea will displace aqueous from
the center of the anterior chamber into the periphery,disloc
ating the iris posteriorly and falsely opening the anterior ch
amber angle.
• Posterior pressure may indent the sclera and falsely narrow
the angle.

45. • Goldmann lens requires an optical coupling
between the cornea and the lens.
( four-mirror Zeiss lens ,Posner, Sussman have a
smaller area of contact and have almost the same
radius of curvature as the cornea, which allows the
tear film to function as the optical coupling agent.)

46. Occludable Angles
During Gonioscopy in situ
(No angle structures are visible)
Optical or Apparent
closure
Appositional closure
Synechial Closure
Look for abnormalities in angle
Manipulative gonioscopy
Indentation gonioscopy

47. To look for angle abnormalities
• Increase the room and slit lamp illumination
• Allow light to impinge on pupil
• Thereby opening up angle

48. Manipulative/Dynamic Gonioscopy
 In eyes with a steep iris configuration
 manipulate Goldmann lens to visualise over
a steep iris
(OVER HILL VIEW)
 Ask patient to look in direction of mirror or
 Move mirror towards angle being viewed

49. Indentation Gonioscopy
 performed in a completely darkened room usi
ng the smallest square of light for a slit beam
to avoid stimulating the pupillary light reflex.
 Effective with Zeiss , Posner, Sussman ,Allen
Thorpe lens whose areas of contact are small
er than the cornea(no coupling media)
 Goldmann and Koeppe have larger areas of c
ontact and may make the angle shallower wit
h indentation

51. • Bending of the cornea results in mechanical rotation of the li
mbus, giving more direct view of the angle
• Permits examiner to look deep into angle recess for
iridodialysis, foreign bodies or cyclodialysis clefts
• By deliberately varying the amount of pressure
applied to the cornea- observe the effects on
angle width.
• Measures extent of angle closure
• Useful in convex iris configuration and Plateau configur
ation - (retain convex profile)
• Performed in all cases
• The ability to visualize angle structures by indentation-redu
ced in the presence of elevated intraocular pressure.

52. • Differentiate form appositional or s
ynechial closure

54. Corneal edema
 In patients with corneal edema ,
 topical anaesthesia followed by Glycerin
 Short lived effect
 In goniotomy, visualisation of edematous corneal epithelium after
it is scraped away after wetting the cornea with 70 % ethyl
alcohol

55. INDICATIONS
• Shallow Ant chamber
• High IOP
• Pigment dispersion
• Pseudoexfoliation
• History of Blunt trauma
• NVI
• Ocular Inflammation
• Compromised Vascular system of Reti
na

56. CONTRAINDICATIONS
• Perforated Globe
• Hyphaema
• Herpes Simplex
• Epidemic Keratoconjunctivitis
• Epithelial basement dystrophies

57. Interpretation of
gonioscopy findings

58. Interpretation of
gonioscopy findings
PUPIL
• looking at the pupil for rapid orientation.
• Anterior lens surface can be observed for focal
opacifications (glaukomflecken) and for poster
ior synechiae.
• View the white dandruff-like flecks of exfoliative
pigment at the posterior edge of the pupil, whi
ch is typical of exfoliative syndrome.
• Iridodonesis is present to a small degree in so
me deep-chambered Normal eyes and is easily
observed if of a pathologic degree.

59. IRIS
• Configuration of the peripheral iris
contour of the iris, noting its flatness -deep anterior
chamber
convexity (or even bowing) -a shallow anterior cham
ber
peripheral concavity -high myopia or
signs of pigment dispersion
• Site of iris insertion
in reference to structures within the angle recess
 at the level of the upper trabecular meshwork and S
chwalbe’s line
 at the level of the filtering trabecular
meshwork
 just below the scleral spur
 below the spur in the ciliary body
 deep posteriorly in the ciliary band.

60. Anteriorly inserting irides, at the level of the spur or
TM -more common among Asians and in patients
with hyperopia.
• Angulation between the iris insertion and the slo
pe of the inner cornea in the angle, in approxima
te steps of 10°.
This systematic assessment of angle anatomy is
the basis of the most detailed gonioscopic gradin
systems.
• Abnormalities such as neovascularization, hypop
lasia,atrophy, and polycoria should be noted.

62. CILIARY BODY BAND
• The ciliary body band appears as a densely pigmented
band just behind Scleral Spur
• dull-brown to slate grey band
• Width depends on position of iris insertion
(Narrower -- hyperopes
wider – myopes )
• If abnormally deep and not symmetrical with the other
eye –
 angle recession
 Cyclodialysis
 unilateral high myopia

63. SCLERAL SPUR
• Site of attachment of longitudinal muscle of Ciliary Body
• Appears as narrow, dense, shiny white band
• Imp. Landmark (relatively consistent appearance)
• Blood in the Schlemm ‘s canal –lies anterior to spur

64. SCHLEMM’S CANAL
• Lies deep to posterior trabeculum
• Normally not visible
• Seen if blood is present in Increased Episcleral V
enous Pressure
– Gonio lens - pressure
– Carotid-cavernous fistula
– Sturge Weber syndrome
– Venous Compression
– Hypotony

65. TRABECULAR MESHWORK
• Pigmented band anterior to Scleral Spur
• Width - 600µm
• Gonioscopic appearance - Ground glass, irregularly roughened due
to large openings of uveal meshwork
• 2 parts
 Anterior - non functional part (White)
 Posterior - functional pigmented part (greyish blue)
primary site of aqueous outflow
• has no pigment at birth, but with age, color develops, from f
aint tan to dark brown, depending on the degree of pigment
dispersion in the anterior chamber.
• distribution of pigment may be homogeneous in some and ir
regular in others.

66. SCHWALBE’S LINE
• Collagen condensation of descement membrane between T.M. and
endothelium
• Thin translucent line or ridge like structure
• The corneal wedge-identifying the schwalbe’s line
• Using a narrow slit beam at an oblique angle
• 2 linear reflections identified from
 external surface of cornea and its junction with sclera
 Internal surface of cornea
Parallelopiped beam of light is seen , apex of which corresponds to
Schwalbe s line.

67. IRIS PROCESSES
• Small extensions from anterior surface of iris to level of Scleral
Spur but sometimes as far anteriorly as schwalbe’s line
• Lacy fenestrated
• Underlying angle structures visible between strands
• Seen in 1/3 rd of normal eyes –not pathological
• Prominent in myopes / brown eyes
• Common in nasal Quadrant

68. Iris Processes
 Lacy fenestrated
 Underlying angle stru
ctures visible between
strands
 Tend to follow
recess
PAS
Iridocorneal adhesions
 Short ,stout projections
 May obscure the scleral spur
 Bridge the recess
 Tether iris to angle and
interfere with posterior
motion of the iris during
Indentation

69. Blood Vessels in the Angle
• Two types
Circumferential vessels
• found at the base of the iris or in the angle recess.
• Appearance- of an undulating “sea serpent”
• with segments of blood vessel visible against the ciliary body, punctuate
d by areas where the vessel dips posteriorly and out of view
• never seen attached to the angle anterior to the scleral spur.
Radial iris vessels within the iris stroma - mimic corkscrews
Normal angle vessel
• Broad
• Appears in short segment
• Not extend anterior to S.S
pur
• Do not arborize in the T.
M
Pathological angle
vessels
• Fine
• Cross the scleral spur
• Branch, arborize in T.M.

70. Sampaolesi line
• Line of irregular pigmentation deposit anterior to
Schwalbe’s line
• sampaolesi’s line can be mistaken for trabecular m
eshwork in narrow angle
Sampaolesi’s Line
Salt , pepper
Dark granular
Discontinuous
Pigmentation T.M
Brown sugar
Fine
Continuous

71. ARTIFACT AND AVOIDANCE
• Use thin slit lamp
•  illumination
• Goldman type lens - avoid indentation- cause ar
tificially narrowing of angle
• Zeiss - avoid pressure  artificial widening of the
angle

72. INTERPRETATION OF
GONIOSCOPIC FINDINGS
• Several grading systems- describe the
width of the anterior chamber angle a
nd its potential for angle closure.
• Shaffer, Scheie, and Spaeth-three most
commonly used systems.

73. ANGLE GRADING SYSTEMS
FOR
GONIOSCOPY

74. SHAFFER’S GRADING
SL to CB
SL to SS
SL to TM
SL only

76. • Spaeth also graded posterior pigmented
meshwork in the 12 o’clock angle on a scale
Of 0 to 4+ and this grade is often assigned
separately at the end of the gonioscopic
description.

77. RECORDING GONIOSCOPIC FINDINGS

78. CLINICAL USES
• Aid in diagnosis of type of glaucoma
 Open Vs closed angle
 Narrow angle
 Cause of sec. Glaucoma
• Decision of iridotomy
• Pre-Operative examination
• Post operative evaluation
 Ostium
 Cleft goniotomy / cyclodialysis
 Iridotomy
• Assess K-F ring (Wilson)
• Therapeutic
 Goniotomy
 Laser procedure (ALT)
 Chamber deepening procedure
 Acute angle closure –break synechia by indentati
on

79. • NEOVASCULARIZATION OF ANGLE:
• Vessels- erratic course and/or extend anteriorly past the level of
the scleral spur.
• Vascular retinal abnormalities such as
 diabetic retinopathy
 retinal venous or arterial occlusions
 ocular ischemic syndrome.
• accompanied by PAS
• Heterochromic cyclitis-
 vessels are fewer, finer
 not accompanied by
peripheral anterior synechiae.
• Healed cataract incision
PATHOLOGICAL FINDINGS

80. PLATEAU IRIS
 Unusual form of primary
angle closure , not by
pupillary block.
 Angle closed by prominent
last roll of iris and
abnormal approach of iris
to angle
 A patent PI or iridotomy
must be present for the
diagnosis
 Ciliary processes –
abnormally forward
 On indentation , central iris
is pushed back but
peripheral iris held up by
ciliary processes

81. PAS IN ANTERIOR UVEITIS

82. Pseudoexfoliation

83. Pigment dispersion syndrome

84. Traumatic Iridodialysis

85. ANGLE RECESSION

86. Iris Bombe

87. Iris Coloboma

88. Posterior Embryotoxon

89. Axenfeld anomaly

91. Malignant melanoma

92. Angle closure-post uveitis

93. Foreign body

94. Aniridia

95. Disinfection
• With all lenses the manufacturer's instructions for disinfection should
be followed to prevent damage to the lens.
• It is important to carefully remove the disinfectant from the contact s
urface before the next use, because alcohol and hydrogen peroxide e
ach cause transient corneal defects.
• Most lenses can be gas-sterilized and some glass lenses can be autoc
laved.
• Most common method is inverting the contact lens and wiping the s
urface with an alcohol sponge.
• lens can be inverted and the concave contact area filled with a
solution of 1: 10 household bleach, which is left for 5 min and then
rinsed off with water.
Adenovirus
type 8
soaking the lens for 5 to 15 minutes in diluted sodium hypochlo
rite (1:10 household bleach), 3% hydrogen peroxide, or 70% is
opropyl alcohol, or by wiping with alcohol, hydrogen peroxide, i
odophor (povidone-iodine), or 1:1000 Merthiolate
HSV Type1 swabbing the lens with 70% isopropyl alcohol
HBV Ten minutes of continuous rinsing in running tap water
HIV-1 Wipe with 3% hydrogen peroxide or 70% isopropyl alcohol swab
s

96. REFERENCES
1.SHIELD ‘S TEXTBOOK OF GLAUCOMA 6th e , by R RAND AL
LINGHAM
2. BECKER –SHAFFER S DIAGNOSIS AND THERAPY OF GLAU
COMAS
3.THE GLAUCOMA BOOK , A PRACTICAL EVIDENCE BASED A
PPROACH TO PATIENT CARE by Paul N. Schacknow
4. HANDBOOK OF GLAUCOMA by Augusto Azuara- Blanco
5.THEORY AND PRACTICE OF OPTICS AND REFRACTION by
A.K. Khurana
6.COLOUR ATLAS OF GONIOSCOPY by Wallace L.M. Alward