2. GONIOSCOPY
1. History of gonioscopy
2. Purpose of gonioscopy
3. Principles of gonioscopy
4. Indications & Contraindications
5. Methods of gonioscopy
6. Procedure of gonioscopy
7 . Sterilisation of the gonio lens
8 . Anatomy of Angle Structures
9 . Grading of Angle Width
10 . Angle abnormalities
11. Diagramatic representation of gonioscopy
12. Summary: Key Points
3. HISTORY OF GONIOSCOPY
The first person to examine the angle of
anterior chamber and coin the term
‘GONIOSCOPY’ was Trantas..
The idea of use of contact lens on cornea was of
Saltzman….later improvised by Koeppe.
The art of gonioscopy & its role in glaucoma
was highlighted by Otto Barkan in 1936.
Subsequently Goldmann introduced gonioprism
in 1938 for simplified view of the angle.
4. PURPOSE OF GONIOSCOPY
WHY DO WE NEED TO PERFORM GONIOSCOPY?
* It is an important part of comprehensive eye examination..its
omission often leads to misdiagnosis!!
* Should be done initially in all glaucoma patients and suspects
* Should be repeated periodically in all cases of angle closure
glaucoma
WHAT SHOULD WE LOOK FOR IN GONIOSCOPY?
• Recognise angle landmarks and consider
• Level of iris insertion
• Shape& profile of peripheral iris
• Estimated angle width
• Degree of trabecular pigmentation
• Any iridotrabecular apposition or synechiae
5. PRINCIPLE OF GONIOSCOPY
The anterior chamber angle is defined as the angle
between anterior surface of iris and posterior
surface of cornea, it cannot be visualised under
direct illumination because the light originating from
here undergoes TOTAL INTERNAL REFLECTION at
the tear–air interface and is reflected back into eye.
WHAT HAPPENS IN GONIOSCOPY?
Only when the light originating from the angle
structures strikes the cornea at an angle steeper than
the CRITICAL ANGLE of 46 degrees,can light exit
the eye & angle structures be visualised. Goniolens
make this possible and neutralise the refractive
power of the cornea thereby helping us visualise the
anterior chamber angle!!!
6.
7.
8. INDICATIONS &
CONTRAINDICATIONS
INDICATIONS
* Narrowness of angle as
observed by van herick’s
technique
* History of angle closure
attack
* History/ evidence of trauma
or penetrating ocular
foreign body
*Active or past inflammation
in chamber
* Evidence of neoplastic
activity in chamber
* Possibility of
neovascularisation
CONTRAINDICATIONS
* Globe rupture
* fresh/ recent hyphema
* Ocular surface infections
like herpes simplex;
epidemic
keratoconjunctivitis
* Epithelial basement
membrane dystrophy
10. TECHNIQUE OF DIRECT
GONIOSCOPY
Koeppe lens( 50 D
diagnostic lens)
available in sizes16mm
(infants) & 18 mm
(adults) is placed with
coupling agent on the
anesthetized cornea of
the supine
patient.viewing is
achieved with a hand
held biomicroscope
and illuminator.
NOTE :
It can be used for
outpatients as well as
in OT
Useful in pediatric
patients
Can also be used to
examine the angle in
patients with
nystagmus
11. DIRECT GONIOSCOPY:
ADVANTAGES:
Straight on view
Variable angle of
visualisation
Panoramic
Angle recession-
comparison
DISADVANTAGES:
Inconvenient
Needs special
equipments
12. INDIRECT GONIOSCOPY
SUCTION TYPE OF
GONIOLENS
Use viscous fluid between
eye & the goniolens.they
provide better image and
require less control;
however are time
consuming & cumbersome
NON SUCTION TYPE
They are good for rapid
evaluation but image is
poor.excess pressure
causes corneal folds
whereas inadequate
pressure can cause entry
of air beneath goniolens
13. GONIOLENS USED IN INDIRECT
GONIOSCOPY
A) 4 MIRROR
B) 3 MIRROR
C) 2 & 1 MIRROR
14. FEATURES:
4 mirror lens: they allow quick examination of all 4
quadrants without any need for rotation of the
goniolens. Eg Zeis, Posner, Sussman.They are non
suction type
3 mirror lens: the D or arc shaped mirror is used for
angle examination, the other two help in viewing
peripheral retina.the central lens helps in macular
examination.the D shaped mirror should be first
placed at 12o’ clock position and eventually rotated
thrice to view the other 3 quadrants.eg. goldmann
2 & 1 mirror lens: they are used in patients with
small interpalpebral fissures.2 mirror lens need to be
rotated once for viewing all quadrants and 1 mirror
needs to be manipulated like the 3 mirror lens.
15. INDIRECT GONIOCOPY: SLIT
LAMP TECHNIQUE
GENERAL GUIDELINES:
Explain the procedure to the patient
Reassure the patient & ensure cooperation
Do an external examination first to rule out corneal abrasion, infection,
edema
Perform tonometry before gonioscopy
Use anaesthesia (4% lignocaine)
Pay attention to patient comfort
Pay attention to alignment by adequately supporting forearm (using an
elbow rest)
Perform examination in dark room
Examiner should use right hand to evaluate left eye & vice versa
Use suitable gonio lens. 3 mirror (suction type ) are best for starters
Disinfect lens prior & after every use
16. SLIT LAMP SETTINGS
10-25X magnification is used
Fairly short and narrow beam
Viewing & illumination arm in same axis.illumination
arm may be moved paraxially to view the temporal &
nasal recess
Focus light on the D shaped mirror
Avoid throwing light into the pupils
Magnification & illumination may be increased to view
finer details like blood vessels and foreign bodies
NOTE: Images are reversed but never crossed!!
17.
18. INDIRECT GONIOSCOPY
ADVANTAGES
* Quick, convenient
and hence preferred
by most
* No special
equipments required
* Allows differentiation
of appositional and
synaechial angle
closure
DISADVANTAGES
* Mirror images can
be confusing
* Inadvertant pressure
on cornea can lead
to (a) narrowing of
angle in goldmann 3
mirror lens (b)
opening of the angle
in 4 mirror lens
19. FACTORS INFLUENCING
FINDINGS IN GONIOSCOPY
PATIENT FACTORS OBSERVER BASED
Pupil size
Lens size
Patient’s cooperation
Entrapment of air between
goniolens & cornea
Excessive pressure causing
corneal folds
Unstable hands
Improper focussing
Lack of experience
20. CLEANING OF THE GONIO
LENS
Soaking in 1:10 bleach for 5-10 mins
Soaking in 2% glutaraldehyde
Rinsing with tap water
NOTE: Though good disinfectants
otherwise; avoid use of isopropyl alcohol
and hydrogen peroxide to rinse suction
type of lens because the weaken the seal
produced by coupling agents
22. ANGLE STRUCTURES
(a) IRIS :
* myopes – concave
* hypermetropes – convex
* abnormal covexity- pupillary block
* abnormal concavity-pigment dispersion
syndrome
* crypts – fuchs’
* abnormal last roll -plateau iris
(b) CILIARY BODY BAND :
*Iris inserts in its concave face
*its width increases in angle recession( scan
circumference), cyclodialysis( cleft seen)
23. (c) SCLERAL SPUR
It signifies the posterior border of trabecular meshwork,
attachment of ciliary body, & insertion of longitudinal
muscles of ciliary body.
Scleral spur might be obscured by
* Iris processes
* iris bombe
* Peripheral anterior synechiae
*Pigments
(d)TRABECULAR MESHWORK
• Most of the aqueous flow is through the posterior TM.it has
intracellular pigment that increases with age.it is identified by
the schwalbe’s line anteriorly & blood in schlemm’s canal and
scleral spur posteriorly
24. (e) SCHWALBE’S LINE
It is the peripheral termination of the Descemet’s
membrane. It is the landmark for identification of TM in
narrow angles.
pigmentation might be seen (sampaolesi’s line).
NOTE:
a) Vessels in angle: this are normally found as well.it might be
the major circle of iridis or radial arteies in iris stroma.
The never cross scleral spur.
b) Pigmentation normally is more defined in the inferior
quadrant….excessive pigmentation in the superior
quadrant is suggestive of some pathology
26. SPAETH SYSTEM OF
CLASSIFICATION (1971)
MAJOR FEATURES STUDIED HERE:
A) Level of insertion of the root of iris
B) Width of the angular recess
C) Configuration of peripheral iris
D) Trabecular meshwork pigmentation
29. LEVEL OF INSERTION OF ROOT
OF IRIS
GRADES:
A) Anterior to schwalbe’s line
B) Behind the schwalbe’s line
C) On the scleral spur
D) Behind the scleral spur deep to
ciliary body face
E) Extremely deep (post ciliary body
band)
31. WIDTH OF THE ANGLE
RECESS
It is estimated by a tangential line from
iris to trabecular meshwork as is
expressed in degrees
Slit
10 degrees
20 degrees
30 degrees
40 degrees
NARROW
WIDE
33. CONFIGURATION OF THE
PERIPHERAL IRIS
It is recorded as
A) Q - queer: anteriorly concave
eg.. High myopes & pigment dispersion syndrome
B) R - regular: anteriorly flat
eg.. Myopes and aphakic
C) S - steep: anteriorly convex
its usually normal; however exaggerated convexity is seen
in hyperopes
PLATEAU IRIS: A flat iris configuration with a peripheral
convex hump in close relation to trabecular meshwork seen
in normal phakic eyes often mimicking narrow angle
34. PIGMENTATION IN THE
POSTERIOR MESHWORK AT 12
O’ CLOCK POSITION
0 - No pigmentation
1 - Trace pigmentation
2 - Mild pigmentation
3 - Moderate pigmentation
4 - Heavy pigmentation
CAUSES OF HEAVY PIGMENTATION:
a)pigment dispersion syndrome
b) pseudoexfoliation syndrome
c) traumatic & uveitic glaucoma
35. OVER THE HILL GONIOSCOPY
Done when the patient
apparently seems to have a
convex / steep iris
configuration or
visualisation of angle
structures is difficult.
Patient hereby is asked to
look in the direction of the
mirror
Alternatively tilt the
goniolens away from the
observation mirror
This helps assessing angle
recess over convex iris
36. INDENTATION ( compression)
GONIOSCOPY
In addition, the spaeth classification also uses the
findings of indentation gonioscopy to distinguish
apposition and synechial angle closure.
The examiner describes the iris insertion as first seen
and then after indentation.
It is usually done in cases with STEEP IRIS
configuration where identification of angle structures
is difficult
The technique involves a routine assessment of all
quadrants following which if an angle is found to be
narrow, each quadrant is reevaluated using a narrow
slit beam( to prevent miosis &artifactual opening of
angle) & pressure is applied in the centre of the eye
37. This helps in deepening of the angular
recess caused by bowing back of peripheral
iris along with stretching of limbal scleral
ring and straightening of angular recess.
Following this one can see structures not
visible earlier or confirm the presence of
peripheral anterior synechiae
If inappropriate pressure is applied, corneal
folds can distort the view
NOTE: Compession gonioscopy isn’t
effective when the IOP is beyond 40 mmHg
as this limits expansion of scleral limbal ring
40. GONIOSCOPY FLOW
DIAGRAM
Scleral spur visible?
NO
DO INDENTATION
GONIOSCOPY
SYNECHIAE (+)
PRIMARY SYNECHIAL ANGLE
CLOSURE
NO SYNECHIAE, RAISED IOP-
PRIMARY APPOSITIONAL
ANGLE CLOSURE
NO SYNECHIAE,NORMAL IOP-
PRIMARY ANGLE CLOSURE
SUSPECT
YES
OPEN ANGLE
41. OTHER ABNORMALITIES IN
ANGLE
Besides abnormalities in angle configuration,
gonioscopy also helps us detect :
A) Peripheral anterior synechiae
B) Neovascularisation of the angle
C) Affects of trauma on angle
D) Specific angle features as in - fuch’s
heterochromatic iridocyclitis, pseudoexfoliation
syndrome, plateau iris etc
E) Tumours of the anterior segment like ciliary body
cysts
F) foreign bodies /silicone oil globules in the angle
G) Early detection of KF Ring
42. IRIS CYST AS SEEN IN (A) SLIT LAMP AND (B)
GONIOSCOPY
48. DISTINGUISHING NORMAL VESSELS
FROM NEOVASCULARISATION OF
THE ANGLE
NORMAL VESSELS
NEOVASCULARISATION OF
THE ANGLE
Radial in orientation
Thick and dull red
Non branching in nature
Do not cross the scleral
spur
Fine and irregular
Bright red
Arborising
Cross the scleral spur
50. POSSIBLE AFFECTS OF TRAUMA
ON ANGLE
ANGLE PECESSION – It is characterised by
a widely visible ciliary body band due to
tear between longitudinal and circular ciliary
muscle fibres. should be followed up
regularly .
CYCLODIALYSIS –disincertion of ciliary
body band from scleral spur, characterised
by deep angle & decreased IOP ; shows a
white band on gonioscopy
INTRAOCULAR FOREIGN BODY
LODGED IN THE ANGLE
LODGED BLOOD CLOTS
53. SPECIFIC ANGLE
CHARACTERISTICS
FUCH’S HETEROCHROMATIC
IRIDOCYCLITIS: Fine fragile vessels
PSEUDOEXFOLIATION SYNDROME:
Sampaolesi’s line & heavily pigmented
trabecular meshwork
PIGMENT DISPERSION SYNDROME:
Abnormal posterior bowing of iris
PLATEU IRIS: Flat configuration iris with
peripheral hump mimicking narrow angle
RAISED EPISCLERALVENOUS PRESSURE
:uniform linear reddish hue (blood in
schlemm’s canal)
54. DIAGRAMATIC
REPRESENTATION
This is the most clinically
useful method of
recording gonioscopic
findings.
Firstly abbreviation for
most posteriorly visible
structure viz.. Ciliary
body(CB), scleral spur(SS),
trabecular meshwork(TM),
schwalbe’s line(SL)
Grading of pigmentation in
each quadrant
Configuration of the iris
Any abnormality in the
angle
56. SUMMARY : KEY POINTS
It is obvious that various angle grades merge
into one another, so the usefulness of any
classification system depends on the skill of
the observer in judging which angles are
potentially or actually occluded &
identifying features of secondary glaucoma
Though simplified to a single grade, the
experienced clinician’s assessment of angle’s
risk for closure takes into account the 3 D
aspects of the angle anatomy, such as level of
iris insertion and peripheral iris
configuration.
57. KEY POINTS …..CONTINUED
Gonioscopy is very much an acquired art ;
and its optimal utilisation requires
considerable personal experience.
Awareness of the sources of error and
proper interpretation of findings results in
shorter learning curve.
Proper long term management of glaucoma
requires gonioscopy at appropriate intervals
because the condition of the angle is not
static throughout life !!
