Gonioscopy

Question 1

An examination of the eye to look at the anterior chamber from the anterior part of the iris to the posterior part of the cornea using the helps of a goniolens and a slit lamp

Answer 1

Gonioscopy

Question 2

Order of the angle

Answer 2

CB
scleral spur
TM
Schwalbes line

Question 3

All the emergent light is subjected to

Answer 3

The total internal reflection

Question 4

Why is the angel hard to see without a gonio

Answer 4

Because the region is covered by a projecting shelf of sclera at the limbus

Question 5

Why use gonioscopy

Answer 5

• fundamental part of a comprehensive eye exam
• most important factor in differential diagnosis (COAG vs angle closure glaucoma)
• done on ALL glaucoma suspects
• repeat periodically for narrow angle or angle closure glaucoma patients

Question 6

What is the most important factor in differential diagnosis for glaucaom

Answer 6

Gonio

Question 7

All four mirrors on the lens is an angle of ______

Answer 7

64 degrees

-eliminates the need for rotating the lens

Question 8

Posterior curvature of the lenses of a goniolens (4 mirrors)

Answer 8

Posterior curvature of all these lenses are equal to that of the cornea which allows the patients own tear film to form the “fluid bridge” between the lens and the surface of the cornea

Question 9

Purpose of 3 mirror gonio

Answer 9

Use this for more than gonioscopy. Can look at different parts of the retina too. Look at retina that us closest to ciliary body and the other two mirrors go a little further back into the peripheral retina

Question 10

Apical mirror of 2 lens

Answer 10

D shaped

• only one that you can use for gonioscopy
• put it on the superior part of the cornea to see the inferior angle

Question 11

Peripheral mirror in a 3 lens

Answer 11

Goes towards the periphery of the retina

-look at the anterior retina

Question 12

Equatorial lens of the 3 mirror

Answer 12

Looking at the equator of the eye

Question 13

From posterior to anterior, what structure should you see in the gonioprism

Answer 13

Ciliary body
Scleral spur
TM
Schwalbes line

Question 14

How to remember the 3 differnt lenses on 3 lens

Answer 14

APE
Apical
Peripheral
Equatorial

Question 15

How to remember gonio structures

Answer 15

I CANT SEE THIS STUFF
I-iris 
C-ciliary 
S-scleral spur
TM
Schwalbes line

Question 16

Deepest angle

Answer 16

Inferior angle

Question 17

Most pigmented angle

Answer 17

Inferior angle

Question 18

Most important angle to look at during gonio

Answer 18

Inferior

Question 19

What mirror will you look at to view the inferior angle

Answer 19

The superior (12 0c lock) one

Question 20

Looking over the hill

Answer 20

• iris is bowed, hard to see over it

- move the mirror over towards the angle you are looking at and it will take you up over the hil (over the iris)

Question 21

How to move the mirror to look over the hill

Answer 21

Towards the angle you are trying to view

Question 22

Difficult angles

Answer 22

Go to the other eye

-most patients have symmetrical eyes

Question 23

Doing a peripheral iridotomy in one eye

Answer 23

You will have to do the other eye

Question 24

A good screening tool before gonio

Answer 24

Von Herrick

Do it in all 4 meridians

Question 25

In van Herrick, the beam is offset ____ temporally to the slit lamp ocular

Answer 25

60 degrees

Question 26

If the anterior chamber depth is as deep as the cornea is thick,

Answer 26

Then the angle is presumed to be wide open

Question 27

Good screening tool before gonio

Answer 27

Von herrick

Question 28

If you cant see anything in one eye on gonio

Answer 28

Look at the other eye, also compare to van Herrick

Question 29

Van herrick grading

Answer 29

4 wide open | Can't see any light- 1

Question 30

Normal vessels in the angle

Answer 30

- radial orientation (not branching) - thick - non-breaching - do NOT cross the scleral spur

Question 31

Neovascularization in the angle

Answer 31

- fine - arborising - crosses scleral spur

Question 32

Corneal wedge

Answer 32

When a thin slit of light hits the irido-corneal angle at an angle of 10-15 degrees - two light reflections are seen from the external and internal corneal surfaces which pipe down at the scleral corneal junction (schwalbes) - this marks the anterior border of the TM

Question 33

Indentation gonioscopy

Answer 33

Ver useful in patients where the iris covers the TM. When that happens, it is easy to mistake - no pigmented TM for scleral spur - pigmented schwalbes line for TM - apposition for synechiae

Question 34

Indentation gonioscopy in glaucoma

Answer 34

Push down on the cornea | Helps open the angle up a little bit so you can see down into there

Question 35

Indentation gonioscopy and synechiae

Answer 35

Won't be abale to break synechiae with this. But you can see it

Question 36

Plateau iris

Answer 36

Need to use indentation gonioscopy to see the angle

Question 37

Scleral spur visible

Answer 37

Yes, grade angle, record findings | Open angle

Question 38

Scleral spur is not visible

Answer 38

-do indentation gonioscopy

Question 39

When doing indentation gonioscopy when you dont see the scalers spur, and you see synechiae

Answer 39

Grade angle Record findings Primary angle closure (synechiae)

Question 40

If you do not find synechiae upon indentation gonio

Answer 40

Check to see is IOPs are raise - yes: grade angle, record findings, primary angle closure, primary angle closure - no: grade angle, record findings, primary angle closure suspect