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Dr. Reshma Peter
GONIOSCOPY
INTRODUCTION
Gonioscopy
allows visualization of
the anterior chamber angle by using
direct or indirect contact lenses to o...
HISTORICAL ASPECTS
 Trantas (1907)
• 1st visualized the anterior chamber angle in a patient with
keratoglobus by indentin...
Anatomy Of the Angle
ANGLE STRUCTURES
PRINCIPLES AND OPTICS
• Critical angle for the cornea-air interface is approximately
46 degrees.
•Total internal reflectio...
L i < L r
light rays are refracted at the contact l
ens-air interface
light rays are reflected by a mirror
light rays leav...
METHODS
• Three primary methods:
• Indirect gonioscopy: Using mirrors,the
angle is examined with reflected light
• Indenta...
GONIOPRISMS(Indirect)
GONIOLENSES(Direct)
Requiring coupling agents Not requiring coupling agents
1.Goldmann single mirror...
GONIOPRISMS
Requiring coupling agents
1.Goldmann single mirror gonioprism
Prototype diagnostic gonioprism
• Mirror incline...
2.Goldmann two mirror gonioprism
• Both mirrors inclined at 62 degrees
• Needs to be rotated once to examine whole
angle
3...
1.Gonioscopy mirror:
• Smallest
• Dome shaped upper border
• Inclination of 59 degrees
Broad area of contact with cornea (...
4.Allen Thorpe gonioprism
• 4 prisms instead of mirrors
• Allows examination of whole angle without rotating the
prisms
• ...
Advantages of Goldmann gonioprisms
• Easy to use
• Excellent view
• Peripheral retina can be seen
• Stabilizes the globe
C...
Disadvantages of Goldmann gonioprisms
• Only 1 mirror for gonio-has to be rotated by 360
degrees
• Cannot be used for inde...
GONIOPRISMS
Not requiring coupling agents
1.Zeiss 4- mirror Gonioprism
• 4 identical mirrors angled at 64 degrees
• On an ...
Zeiss 4- mirror Gonioprism
ADVANTAGES DISADVANTAGES
• Easy to perform
• All 4 quadrants visible at sa
me time
• Rotation o...
2.Posner Gonioprism
• Similar to Zeiss
• Made of plastic instead of glass
• Has a fixed handle
3.Sussman lens
Similar to Zeiss
but has no handle
4.Tokel Gonioprism
• Single mirror lens
• Broader viewing area
than Gold...
5.Ritch Trabeculoplasty laser lens
• 2 mirrors tilted at 59degrees to see inferior angle
• 2 mirrors at 64 degrees to view...
GONIOLENSES
Koeppe lens
• Prototype diagnostic lens
• Available in several sizes
• Most commonly used lens
for diagnostic ...
Swan jacob’s
lens
• Surgical goniolens
• used in children
Richardson Shaffer’s lens
Small lens for use in infants
Worth go...
DIRECT GONIOSCOPY
• Patient in Supine position
• 4 %Xylocaine as topical anaesthesia
• Saline bridge the gap between lens ...
TOTAL MAGNIFICATION
MAGNIFICATION DUE
TO KOEPPE LENS
MAGNIFICATION DUE TO
MICROSCOPE
x 1.5 x 16
X 24
• Offers a panoramic, less magnified view than
indirect gonioscopy.
• Less likely to exert pressure upon the cornea or
lim...
Advantages of Direct
Gonioscopy
 The height of the observer may be changed to
look deeper into a narrow angle, whereas th...
 Goniolens may cause less distortion of the ante
rior chamber
 Using 2 lenses,both eyes can be
simultaneously examined
...
Disdvantages of Direct
Gonioscopy
 Inconvenient
 Annoying light reflexes from the cornea
 Timeconsuming
 Benefits of s...
INDIRECT GONIOSCOPY
PROCEDURE
 Dim illumination
 Eye anaesthetised with topical agent
 Appropriate positioning of the p...
The concave face of Goldmann lens should be filled with a Methyl
cellulose coupling fluid before its applied to the eye.
C...
 Patient is asked to look down
 Thumb used to retract the upper eyelid
 Lower edge of gonioscope placed on inferior scl...
Slit lamp gonioscopy
• The part that is viewed is 180 degrees away from
the mirror that is being used.
• Slit lamp beam is...
• With a narrow, short slit beam off axis, the quadrant o
f the angle to be assessed is first examined with the f
our-mirr...
Illumination methods
Diffuse illumination Focal illumination with a
broad beam
Focal illumination with a narrow beam
• Using a narrow slit beam at an oblique angle
• 2 linear reflections identified from
 external surface of cornea and its...
Advantages of Indirect
Gonioscopy
• Easier to learn
• Faster to perform, particularly with the Zeiss
four-mirror lenses an...
• Gonioprisms with taller mirrors facilitate
visualization of narrow angles.
• The slit beam can create a corneal wedge to...
Disadvantages of Indirect
Gonioscopy
• Limited positioning of light rays
• Comparison not possible
• Difficult to perform ...
• Goldmann lens requires an optical coupling
between the cornea and the lens.
( four-mirror Zeiss lens ,Posner, Sussman ha...
Occludable Angles
During Gonioscopy in situ
(No angle structures are visible)
Optical or Apparent
closure
Appositional clo...
To look for angle abnormalities
• Increase the room and slit lamp illumination
• Allow light to impinge on pupil
• Thereby...
Manipulative/Dynamic Gonioscopy
 In eyes with a steep iris configuration
 manipulate Goldmann lens to visualise over
a s...
Indentation Gonioscopy
 performed in a completely darkened room usi
ng the smallest square of light for a slit beam
to av...
• Bending of the cornea results in mechanical rotation of the li
mbus, giving more direct view of the angle
• Permits exam...
• Differentiate form appositional or s
ynechial closure
Corneal edema
 In patients with corneal edema ,
 topical anaesthesia followed by Glycerin
 Short lived effect
 In goni...
INDICATIONS
• Shallow Ant chamber
• High IOP
• Pigment dispersion
• Pseudoexfoliation
• History of Blunt trauma
• NVI
• Oc...
CONTRAINDICATIONS
• Perforated Globe
• Hyphaema
• Herpes Simplex
• Epidemic Keratoconjunctivitis
• Epithelial basement dys...
Interpretation of
gonioscopy findings
Interpretation of
gonioscopy findings
PUPIL
• looking at the pupil for rapid orientation.
• Anterior lens surface can be o...
IRIS
• Configuration of the peripheral iris
contour of the iris, noting its flatness -deep anterior
chamber
convexity (or ...
Anteriorly inserting irides, at the level of the spur or
TM -more common among Asians and in patients
with hyperopia.
• An...
CILIARY BODY BAND
• The ciliary body band appears as a densely pigmented
band just behind Scleral Spur
• dull-brown to sla...
SCLERAL SPUR
• Site of attachment of longitudinal muscle of Ciliary Body
• Appears as narrow, dense, shiny white band
• Im...
SCHLEMM’S CANAL
• Lies deep to posterior trabeculum
• Normally not visible
• Seen if blood is present in Increased Episcle...
TRABECULAR MESHWORK
• Pigmented band anterior to Scleral Spur
• Width - 600µm
• Gonioscopic appearance - Ground glass, irr...
SCHWALBE’S LINE
• Collagen condensation of descement membrane between T.M. and
endothelium
• Thin translucent line or ridg...
IRIS PROCESSES
• Small extensions from anterior surface of iris to level of Scleral
Spur but sometimes as far anteriorly a...
Iris Processes
 Lacy fenestrated
 Underlying angle stru
ctures visible between
strands
 Tend to follow
recess
PAS
Irido...
Blood Vessels in the Angle
• Two types
Circumferential vessels
• found at the base of the iris or in the angle recess.
• A...
Sampaolesi line
• Line of irregular pigmentation deposit anterior to
Schwalbe’s line
• sampaolesi’s line can be mistaken f...
ARTIFACT AND AVOIDANCE
• Use thin slit lamp
•  illumination
• Goldman type lens - avoid indentation- cause ar
tificially...
INTERPRETATION OF
GONIOSCOPIC FINDINGS
• Several grading systems- describe the
width of the anterior chamber angle a
nd it...
ANGLE GRADING SYSTEMS
FOR
GONIOSCOPY
SHAFFER’S GRADING
SL to CB
SL to SS
SL to TM
SL only
• Spaeth also graded posterior pigmented
meshwork in the 12 o’clock angle on a scale
Of 0 to 4+ and this grade is often as...
RECORDING GONIOSCOPIC FINDINGS
CLINICAL USES
• Aid in diagnosis of type of glaucoma
 Open Vs closed angle
 Narrow angle
 Cause of sec. Glaucoma
• Deci...
• NEOVASCULARIZATION OF ANGLE:
• Vessels- erratic course and/or extend anteriorly past the level of
the scleral spur.
• Va...
PLATEAU IRIS
 Unusual form of primary
angle closure , not by
pupillary block.
 Angle closed by prominent
last roll of ir...
PAS IN ANTERIOR UVEITIS
Pseudoexfoliation
Pigment dispersion syndrome
Traumatic Iridodialysis
ANGLE RECESSION
Iris Bombe
Iris Coloboma
Posterior Embryotoxon
Axenfeld anomaly
Malignant melanoma
Angle closure-post uveitis
Foreign body
Aniridia
Disinfection
• With all lenses the manufacturer's instructions for disinfection should
be followed to prevent damage to th...
REFERENCES
1.SHIELD ‘S TEXTBOOK OF GLAUCOMA 6th e , by R RAND AL
LINGHAM
2. BECKER –SHAFFER S DIAGNOSIS AND THERAPY OF GLA...
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Gonioscopy

  1. 1. Dr. Reshma Peter GONIOSCOPY
  2. 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. 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. 4. Anatomy Of the Angle
  5. 5. ANGLE STRUCTURES
  6. 6. 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.
  7. 7. 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
  8. 8. 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.
  9. 9. 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
  10. 10. 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
  11. 11. 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
  12. 12. 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
  13. 13. 4.Allen Thorpe gonioprism • 4 prisms instead of mirrors • Allows examination of whole angle without rotating the prisms • Suspended by a frame
  14. 14. Advantages of Goldmann gonioprisms • Easy to use • Excellent view • Peripheral retina can be seen • Stabilizes the globe Can be used in Argon Laser trabeculoplasty
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. 2.Posner Gonioprism • Similar to Zeiss • Made of plastic instead of glass • Has a fixed handle
  19. 19. 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
  20. 20. 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
  21. 21. 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
  22. 22. 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
  23. 23. 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.
  24. 24. TOTAL MAGNIFICATION MAGNIFICATION DUE TO KOEPPE LENS MAGNIFICATION DUE TO MICROSCOPE x 1.5 x 16 X 24
  25. 25. • Offers a panoramic, less magnified view than indirect gonioscopy. • Less likely to exert pressure upon the cornea or limbus, causing errors
  26. 26. 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
  27. 27.  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
  28. 28. Disdvantages of Direct Gonioscopy  Inconvenient  Annoying light reflexes from the cornea  Timeconsuming  Benefits of slit lamp not available
  29. 29. INDIRECT GONIOSCOPY PROCEDURE  Dim illumination  Eye anaesthetised with topical agent  Appropriate positioning of the patient at slit lamp
  30. 30. 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
  31. 31.  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
  32. 32. 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.
  33. 33. • 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
  34. 34. Illumination methods Diffuse illumination Focal illumination with a broad beam
  35. 35. Focal illumination with a narrow beam
  36. 36. • 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
  37. 37. 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.
  38. 38. • 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
  39. 39. 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.
  40. 40. • 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.)
  41. 41. 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
  42. 42. To look for angle abnormalities • Increase the room and slit lamp illumination • Allow light to impinge on pupil • Thereby opening up angle
  43. 43. 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
  44. 44. 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
  45. 45. • 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.
  46. 46. • Differentiate form appositional or s ynechial closure
  47. 47. 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
  48. 48. INDICATIONS • Shallow Ant chamber • High IOP • Pigment dispersion • Pseudoexfoliation • History of Blunt trauma • NVI • Ocular Inflammation • Compromised Vascular system of Reti na
  49. 49. CONTRAINDICATIONS • Perforated Globe • Hyphaema • Herpes Simplex • Epidemic Keratoconjunctivitis • Epithelial basement dystrophies
  50. 50. Interpretation of gonioscopy findings
  51. 51. 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.
  52. 52. 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.
  53. 53. 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.
  54. 54. 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
  55. 55. 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
  56. 56. 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
  57. 57. 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.
  58. 58. 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.
  59. 59. 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
  60. 60. 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
  61. 61. 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.
  62. 62. 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
  63. 63. 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
  64. 64. 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.
  65. 65. ANGLE GRADING SYSTEMS FOR GONIOSCOPY
  66. 66. SHAFFER’S GRADING SL to CB SL to SS SL to TM SL only
  67. 67. • 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.
  68. 68. RECORDING GONIOSCOPIC FINDINGS
  69. 69. 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
  70. 70. • 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
  71. 71. 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
  72. 72. PAS IN ANTERIOR UVEITIS
  73. 73. Pseudoexfoliation
  74. 74. Pigment dispersion syndrome
  75. 75. Traumatic Iridodialysis
  76. 76. ANGLE RECESSION
  77. 77. Iris Bombe
  78. 78. Iris Coloboma
  79. 79. Posterior Embryotoxon
  80. 80. Axenfeld anomaly
  81. 81. Malignant melanoma
  82. 82. Angle closure-post uveitis
  83. 83. Foreign body
  84. 84. Aniridia
  85. 85. 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
  86. 86. 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
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