2. What is Gonioscopy
• Gonioscopy is an examination of the eye to
look at the anterior chamber from the ant.
part of iris to the post. part of cornea using
the help of gonio-lens and slit lamp.
4. Pioneer
• Alexios Trantas : The first person to examine
angle in the Anterior chamber in a living eye.
• In 1900 with the aid of direct
ophthalmoscopy and stimulating digital
pressure on corneo-scleral capsule he
examined – ciliary body, ora serrata and , the
anterior chamber .
1901 – Gazette Medicale d’Orient.
5. • Maximilian Salzmann: He reported that light
that emanates from the angle undergoes
‘total internal reflection’ and thus, cannot be
intercepted by ophthalmoscope due to change
in medium
• He indicated that indirect ophthalmoscopy
give’s a better view of angle than that of direct
ophthalmoscopy.
• He later calculated that the lens with smaller
radius of that of cornea would facilitate
Gonioscopy (Zeiss scleral contact lens 7mm).
6. Impact Of Slitlamp Biomicroscopy
• 1920- Zeiss perfected the first slitlamp basing
on principle of Noble laureate Allvar
Gullstrand (Sweden) and Czapski’s corneal
microscope.
• Koeppe (Germany) : Mathematically
calculated the most adv. Contact lens and gave
the method biomicroscopy of angle of ant.
Chamber with slit lamp (magni. – 40 dia)
7. • He could see the nasal and temporal aspects
of angle in sitting position of patient with the
help of new more convex and thicker lens.
• Koeppe’s method improvised by Ascher and
used on recumbent patients made it possible
to visualizing inferior and superior angles
• Koeppe’s method is still been used for direct
gonioscopy without reflecting surface
8. The American Pioneer
• Manuel Uribe Troncoso: Involved in
Gonioscopy due to interest in glaucoma
• 1925-Discribed self illuminating mono-ocular
Gonioscopy with its complex arrangment of
reflecting prisms ( mag: 30 dia)
• 1941- Discribed chamber angles in various
glaucoma’s
• 1947 – Wrote first comprehensive book on
Gonioscopy
• Clarified the anatomical terminology of
structures of angle seen in Gonioscopy.
9. Otto Barkan
• He combined Koeppe’s contact lens, the light
powerful Vogt carbon-arc slit lamp and Zeiss
binocular microscope which gave 40x mag.
• He coined the term ‘open angle glaucoma’
and suggested that, sclerosis of trabecular
meshwork was the cause for raise in IOP
• He devised internal trebeculectomy under
microscopy which spurned to todays external
trebeculectomy and trebeculectomy
10. Contd…
• He was able to correlate the raise of IOP in
eyes with narrow angle glaucoma with closure
of angle by root of iris naming ‘narrow angle
glaucoma’ and advocated peripheral
iridectomy as a cure.
• Barkan and Maisler studied the exact
topography of angle structures .
11. Goldmann’s Gonioscopy
• It was Goldmann a Swizz Ophthalmologist in
Prague who popularised gonioscopy in Europe,
not only by introducing a simple and superior
method of examination but, also through his
papers which confirmed Barkan’s observations.
• Allen, Braley and Thorpe (1945) with four
reflecting surfaces gave a miter shaped
gonioscope where external curvature of koeppe
lens was replaced by a prism which stayed on the
cornea by capillary attraction.
12. Why do we need Gonioscopy
• As the recesses of the angle of anterior
chamber are difficult to visualize since this
region is covered by projecting shelf of sclera
at the limbus and all the emergent light is
subjected to total internal reflection.
13. Why do we need Gonioscopy
• Fundamental part of comprehensive exam
• Most important factor in correct diagnosis
• Done initially for all glaucoma patients and
suspects
• Repeated periodically for all angle – closure
glaucoma patients
14. Purpose of Gonioscopy
• Visualization of anterior chamber angle
• View of peripheral iris
• Difference between angle – closure,
occludable, and secondary glaucomas
15. Other ways to evaluate the angle
Scheimpflup photography
Ultrasound biomicroscopy
18. Criticle angle
• When light is passing from a medium with
greater refractive index to one with lesser
refractive index angle of refraction (r)will be
larger than angle of incidence(i)
• Critical angle is where ‘r’ = 90⁰
• When ‘I’ exceeds critical angle the light is
reflected back into the medium
• Critical angle for corneal-air interface = 46⁰
• Light from A.C. angle as exceeds the critical
angle is reflected back into the anterior
chamber leading to ‘ Total internal reflection’
22. Common Goniolens and Types
lens
description
1. Indirect goniolens
•
goldmann single mirror
Mirror inclined at 62⁰
• Zeiss four mirror
All mirrors at 64⁰ , no fluid bridge requried
• Posner four mirror
Modified Zeiss with handel
• Sussman four mirror
Hand held Zeiss model
• Ritch Trabeculoplasty lens
Four mirror’s : 2 at 59⁰ and 2 at 62⁰ , with a
convex lens over two of the mirror’s
2. Direct goniolens
• Koeppe
Dome shaped lens
• Barkan
Quarter sphere, surgical and diagnostic lens
• Swan-Jacob
Surgical goniolens for children
24. Direct Gonioscopy
• Advantages
– Observer’s height can be changed
to look deep or get a better look
at the angle structre’s
– As done in supine position it can
be used for sedated, comatosed,
or in children
– Useful in examining the fundus
with small pupil with D.O
– Straight on the view
– Panoramic view of the angle
structure’s
– Comparison of angle recession
– Causes less distortion of A.C.
26. Indirect Gonioscopy
• Instrument's used : gonioprism and a slitlamp
• Most widely used gonioprisum : Goldmann
– Goldman single mirror
•
•
•
•
Height of the mirror : 12 mm
Angle of the mirror : 62 ⁰
Central well diameter : 12mm
Posterior radius of curvature : 7.38 mm
– Goldmann three mirror
• One mirror for examination of anterior chamber : 59⁰
• Two mirror’s for examination of fundus.
• The posterior radius of curvature is such that both the
lens need viscous material to fill the space
27. • Contd…
• Modified Goldmann lens have been
developed
– One with a posterior curvature of 8.4 mm
eliminating the need of a viscous material
– Another with a anti-reflecting coat used in laser
trabeculoplasty
31. Four mirror lens
• Zeiss four mirror lens, all at an angle of 64⁰
eliminating the need for rotating
• Original four mirror is on a Unger Holder
• Posner has a fixed holder
• Sussman is held directly
• Posterior curvature of all these lens is equal to
that of cornea which allows the patien’s own
tears to form the fluid bridge
40. What to see
• While performing a direct or an indirect
Gonioscopy and starting from the root of the
iris and moving anteriorly to cornea the
structure’s to be identified and examined are
1)
2)
3)
4)
5)
Ciliary body band
Scleral spur
Functional trabecular meshwork
Schwalbe’s line
Normal blood vessels
42. Pupil
• It is best to start at the pupil for rapid
orientation
• Anterior lens surface is observed for focal
opacification and posterior synechiae
• This position is also good for examining
dandruff flake's like exfoliations on the
pigment at the posterior edge of pupil –
Exfoliation syndrome
• Iridodonesis – to a small extent seen in normal
eye and easily observed in pathognomic one
43. Angle Structures : Iris
• Contour
– flat – deep A.C
– Convex – shallow A.C. ,
hyperopia
– Concave – high myopia,
pigment dispersion synd.
– Abnormal last rolling –
plateau iris
44. Angle Structures : Iris
• Site of insertion : while examining the iris care
should be taken in distinguishing the apparent
and actual juncture
• This is established by the use of indentation
Gonioscopy
• Angulation : It is the angle between iris
insertion and slope of the inner cornea in the
A.C .( 10⁰)
• Abnormalities : neovascularization,
hypoplasia, atrophy
45. Angle Recess
• Is seen beyond the final roll of iris
• At birth – incomplete
• 1sr yr of life it firms a concavity into the
anterior surface of the ciliary body
46. Angle Structures : Ciliary Body band
• This structural portion of
ciliary body is visible in the
A.C. as a result of iris
insertion
• Width depends on level of
iris insertion
• Wider in myopes and
narrow in hyperopia
• Color: grey to dark brown
47. Angle Structures : Scleral Spur
• This is the post. Lip of scleral
sulcus which is attached to the
ciliary body posteriorly and
corneo-scleral meshwork
anteriorly
• Color : prominent white line
48. Angle Structures : Scleral Spur
• May be obscured by
– Iris process
– iris bombe
– Peripheral anterior synechiae
– pigments
49. Angle Structures :
Trabecular Meshwork
• Pigmented band anterior to scleral spur
• Although extent of TMW is from root of iris to
schwalbe’s line it is considered as 2 portions
a) Anterior - between schwalbe’s line and ant. Edge
of schlemm’s cannal
• Involved in lesser degree of aqueous out flow
b) Posterior – Functional part , primary site of
aqueous out flow
• Appearance of funtional TMW depends on
amount of pigmant deposition
50. Angle Structures :
Trabecular Meshwork
• At birth no pigment and
with age from faint to
dark brown
• Pigment deposition may
be homogeneous or
irregular
• When lightly pigmented
blood reflex in
schlemm’s cannal may
be seen as a red band
51. Angle Structures : Schwalbe’s line
• Junction between anterior
chamber angle structures and
cornea where the descement’s
membrane terminates
• Fine ridge ant. to TMW identified
by a small built up of pigment
• Landmark for TMW in narrow
angle
56. Manipulation's
• Sometimes the iridocorneal angle is quite
confusing
• Often the angle is difficult to interpret
because there is too much or too little angle
pigmentation
• In such cases manipulation’s are used for
better viewing and diagnosis
57. Technique for examining difficult
angle’s
•
•
•
•
Looking over the hill
Corneal wedging
Indentation
Van-Hericks test
58. Look over the hill
• WHAT ? Sometimes the iris is bowed forward
making visualization of the iridocorneal angle
quite challenging
• WHERE ? Open angle with iris bowing ,
cholinergic agents such as pilocarpine
• WHY ? To know weather the angle is occluded
or not
60. Corneal Wedge
• WHAT ? When a thin slit of light hits the iridocorneal angle at an angle of 10⁰-15⁰, two light
reflections are seen from the external and
internal corneal surfaces which pipe down at
the sclero-corneal junction (Schwalbe’s line)
marking the anterior border of trabecular
meshwork
61. • WHY ? corneal wedge is a useful technique to
identify the trabecular meshwork in eyes that
are either nonpigmented or excessively
pigmented its diff. to mark trabecular
meshwork begins
• WHERE ? Young patients where the trabecular
meshwork has not yet developed any
pigmentation
• WHY ? To diff. wide-open and nonpigmented
angle or a totally closed angle where one is
looking at the internal cornea.
64. Indentation Gonioscopy
• When iris covers the trabecular meshwork
(TM) its easy to mistake:
– The non-pigmented TM for scleral spur
– Pigmented Schwalbe’s line for TM
– Apposition from synechiae
• Indentation Gonioscopy is particularly useful
in these cases
65. Indentation Gonioscopy
• Useful when iris surface is convex
– Done when recognition of angle structures is
difficult
• Performed in all glaucoma cases
– Differentiates appositional vs synechial closure in
pupillary block
– Measures extent of angle closure
– Identifies plateau iris config.
– Identifies lens induced angle closure
74. VAN HERICK’S method of cornael
thickness as a unit of measure
• WHAT ? The Van Herick test is a slit lamp
estimation of the angle depth
• WHY ? To estimate the angle width
• WHERE ? In nonpigmented angles it can be
difficult to determine whether the angle is
open or closed
75. 5%
15%
25%
40%
75%
100%
Thin bright slit 60⁰ from temporally is brought into cornea until
A.C. is located compared with depth of peripheral A.C. If the
depth of the A.C = corneal thickness then it’s a wide open angle
80. Difficulties in gonioscopy
• Koeppe’s lens: Scleral lip pressing on outer
sclera causing narrowing of angle
• Zeiss lens: excessive pressure on central
cornea causes angle widening and
descement’s folds
• Air or methylcellulose collected on inner
surface removed with soap water
• All lenses cleaned with dil.bleach or hydrogen
peroxide after use
