Gonioscopy

Question 1

van herrick angle estimation is a ratio of what?

Answer 1

ratio of width of peripheral AC to the width of the cornea

Question 2

what can a deep anterior chamber suggest?

Answer 2

may be suggestive of pigment dispersion syndrome

Question 3

define gonioscopy

Answer 3

a procedure used in the evaluation of the peripheral anterior chamber angle

Question 4

indications for gonioscopy

Answer 4

• evaluation of narrow anterior chamber angle prior to dilation
• differential diagnosis of angle closure
• differential diagnosis of open angle GLC
• evaluation of iris contour changes
• rule out neovascularization of the iris
• history of blunt trauma

Question 5

contraindications for gonioscopy

Answer 5

• hyphema
• recent refractive surgery
• compromised corneas (epithelial damage)
• perforated eyes
• lacerations

Question 6

list 3 mirrors of the goldmann 3 mirror lens

Answer 6

1. apical mirror (bullet)
2. peripheral mirror (square)
3. equatorial mirror (trapezoid)

Question 7

mirror and degree used in angle viewing and ora serrata

Answer 7

apical (bullet), 59 degrees

Question 8

mirror and degree used in peripheral retinal evaluation

Answer 8

peripheral mirror (square), 67 degrees

Question 9

mirror and degree used in equatorial retinal region evaluation

Answer 9

equatorial mirror (trapezoid), 73 degrees

Question 10

which mirror system is more versatile, clearer views, better for blepharospasm, and adheres to the eye on the central axis?

Answer 10

3 mirror

Question 11

which mirror system is used for compression gonioscopy

Answer 11

4 mirror

Question 12

which mirror system uses little to no fluid, has a rapid assessment of the angle, is less traumatic to the eye, but requires more dexterity

Answer 12

4 mirror

Question 13

what can indentation or compression gonioscopy assess and be used for?

Answer 13

• assess if appositional closure or PAS present

- can be used to break ACG attack, lower IOP

Question 14

how does indentation or compression gonioscopy work?

Answer 14

directs aqueous towards the peripheral anterior chamber and pushes the peripheral iris back to view the angle

Question 15

how does “dynamic gonioscopy” and what does it allow for?

Answer 15

• allows for a better view over a very convex peripheral iris
• tilt or slide the lens towards the angle being viewed or have patient look into the mirror

Question 16

list structures you see in gonioscopy from posterior to anterior

Answer 16

-iris
-ciliary body
-scleral spur
-trabecular meshwork
(pigmented then non-pigmented)
-Schwalbe’s line

Question 17

color, width and visibility of ciliary body

Answer 17

color: light grey to light brown, charcoal grey in darker irides
width: 0.5 mm (wider may indicate angle recession)
visibility: may be obscured by iris processes or iris

Question 18

what is the scleral spur and what is the color/ appearance?

Answer 18

• a fibrous ring that attaches the CB to TM

- color is white and appearance is a radial ring that may be obscured by iris or iris processes

Question 19

which structure of the trabecular meshwork is most posterior?

Answer 19

pigmented

Question 20

what is important about the pigmented structure of the trabecular meshwork?

Answer 20

• filtering portion of the angle

- Schlemm’s canal next to SS

Question 21

when is Schlemm’s canal visible?

Answer 21

when episcleral venous pressure increases

red

Question 22

pigment in the TM does not occur before:

Answer 22

puberty

Question 23

when does pigment in the TM increase?

Answer 23

• in pregnancy
• with age
• with iris colors

Question 24

list some other related changes to pigment in the TM

Answer 24

• pigment dispersion syndrome
• previous injuries or surgeries
• exfoliation
• open angle glaucoma
• previous uveitis

Question 25

list grading scale and definitions for pigment in TM

Answer 25

``` 0- granular, fine, gray color trace 1+: scattered pigment/ slightly brown 2+: definitely visible brown pigment 3+: dense pigment band 4+: pigment on the iris, SS, CB (extremely thick and dense) ```

Question 26

what is the "termination of Descemet's in the angle?

Answer 26

Schwalbe's Line

Question 27

What is the anterior limit of the angle wall and the junction of the anterior and posterior cornea lines

Answer 27

Schwalbe's Line

Question 28

describe the appearance of Schwalbe's line

Answer 28

thin white glistening line which acts as a "shelf" where pigment may collect inferiorly

Question 29

what is posterior embryotoxon

Answer 29

15% of eyes have Schwalbe's line anteriorly displaced

Question 30

when evaluating Schwalbe's line, what is "Sampaolesi's line"?

Answer 30

a wavy line of pigment seen in exfoliation patients

Question 31

list 3 common "sightings" in the angle

Answer 31

- iris processes - sampaolesi's line - blood in Schlemm's canal

Question 32

the unwanted "guests" in the angle

Answer 32

- synechiae | - neovascularization (diabetic retinopathy)

Question 33

3 reasons why you may see blood in schlemm's canal

Answer 33

- excessive pressure from gonio lens - increased episcleral venous pressure - low IOP

Question 34

what should you look for and what conditions can cause blood in Schlemm's canal from increased episcleral venous pressure

Answer 34

look for engorged episcleral veins - cavernous sinus fistula - thyroid disease - Sturge-Weber

Question 35

Becker Shaffer 4

Answer 35

ciliary body

Question 36

Becker Shaffer 3

Answer 36

scleral spur

Question 37

Becker Shaffer 2

Answer 37

anterior TM

Question 38

Becker Shaffer 1

Answer 38

anterior TM/ SChwalbe's line

Question 39

Becker Shaffer 0

Answer 39

no visible structures

Question 40

what is the Spaeth criterion?

Answer 40

alphanumeric documentation - details 3D dimensional details of the angle - high correlation to OCT and UBM findings

Question 41

how you you grade in Spaeth criterion?

Answer 41

made up for sup (narrowest) and inferior (widest) - site of iris insertion - angle width - configuration of peripheral iris - trabecular meshwork pigment

Question 42

iris insertion in Spaeth criterion grading

Answer 42

``` A- anterior to Schwalbes B- behind Schwalbes and scleral spur C- scleral spur visible D- deep CB visible E- extremely deep >1mm of CB visible ```

Question 43

with of angle recess in Spaeth criterion grading is:

Answer 43

width of angle recess can be 0, 10, 20, 30, 40

Question 44

peripheral iris configuration for Spaeth criteria

Answer 44

- steep (bowed (b) or plateau (p)) - regular or flat - queer or concave

Question 45

pigment in TM for Spaeth criteria

Answer 45

minimal to no pigment: grade 1 | up to dense pigment: grade 4

Question 46

list of angle closure from slight risk to extremely risky

Answer 46

- TM without iris bow - TM with iris bow - 1/2 TM without iris bow - 1/2 TM with iris bow - Schwalbe's line

Question 47

documentation requirements

Answer 47

- which eye, which angle - most posterior structure - about of pigmentation - iris approach (flat, moderate or bowed) - angle anomalies (iris processes, sampolesis line, pigment above Schwalbes)

Question 48

convexity more common in

Answer 48

hyperopia, malignant glaucoma, plateau iris, angle closure | increases in cataract

Question 49

concavity more common in

Answer 49

myopia, aphakia, pigment dispersion

Question 50

irregular iris in

Answer 50

synechiae, iris or CB tumor, lens dislocation, iris cyst

Question 51

gonio billing specifics

Answer 51

92020 (OU, 1x/year) -can code with 92012 -need to have associated code (narrow angles, glaucoma suspect, glaucoma)

Question 52

problems with Van Herick:

Answer 52

- only measures "apparent depth" - iris appears closer - typically underestimating angles

Question 53

what is the SL-OCT good for?

Answer 53

- angle assessment | - iris configuration