Gonioscopy

1. GONIOSCOPY
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2. WHY DO WE NEED GONIOSCOPY
?
• Owing to lack of transparency of the corneoscleral junction and total
internal refraction of light at anterior surface of cornea it is not possible to
visualise the angle of anterior chamber directly. Therefore a device
(goniolens) is used to divert the beam of light and this technique of bio
microscopic examination of angle of anterior chamber is called
GONIOSCOPY

3. PRINCIPLE
It over comes the total internal
reflection . It has a critical angle
of 46*. The gonoscpe with the
same refractive index as cornea
light from the anterior chamber
strikes the corena and travels
through and gets reflected by the
mirror in the GONIOSCOPE
,thus reaching the eye

4. TYPES OF
GONIOLENS
1. INDIRECT GONIOLENS-
provides mirror image of opposite
angle Eg - Goldman and
Zeiss goniolens
Mostly used for surgical procedures
,used in bed ridden patients
,anaesthetise patients

5. 2. DIRECT GONIOLENS- direct
view of the angle
Eg - Koeppe goniolens most
popular used for diagnostic
procedure

7. PROCEDURE
• The patient is made to sit upright on the slit lamp
• A drop of methyl cellulose 1% is placed on the con cavity of the goniolens
• One edge of the lens is positioned on the lower fornix and upper eyelid is
elevated
• The patient is ask to look straight where the lens is positioned against the
eye checking for lateral and medial angles
• The slit beam should be horizontal when checking the superior and inferior
angles

8. ANGLE STRUCTURES
I Can’t See This Stuff
• Root of the iris
• Anteromedial surface of ciliary body
• Scleral spur
• Trabecular mesh work
• Schwalbe‘s line

9. APPLICATIONS OF
GONIOSCOPY
• Classification of glaucoma into open and closed angle based on
configuration
• Localization of foreign bodies ,abnormal vessels or tumours of the angle
• Demonstration of peripheral anterior synechiae (PAS)to plan extent of
glaucoma surgery
• Surgical aid direct goniolens is used during goniotomy

10. GONIOSCOPIC GRADING OF ANGLE
WIDTH
• 3 GRADING SYSTEM MOST COMMONLY USED SHAFFER
• SCHEIE: Based on number on structures visible .
• : All structures visible - Grade 1 - angle open
• : 3 structures visible - Grade 2
• :2 structures visible- Grade 3
• : only Schwalbe’s - Grade 4

12. https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.aao.org/ed
ucation/basic-skills/general-
techniques&ved=2ahUKEwiyu97X8_v_AhVgamwGHXmrAK8Qo7QBegQIARAB&usg=AOvVa
w2287Vb6xMJlLm_8tDfGhcN