Clinical: Biomicroscopy And Illumination Techniques

Question 1

What is the anterior chamber?

Answer 1

The space between the cornea and the iris/lens

Question 2

What is the anterior chamber filled with?

Answer 2

Aqueous humor

Question 3

What is aqueous humor?

Answer 3

Clear fluid secreted by the ciliary body

Question 4

How does aqueous humor travel through the eye?

Answer 4

Via the pupil and exits through the trabecular meshwork

Question 5

Where is trabecular meshwork located?

Answer 5

In the anterior chamber angle

Question 6

What is the issue with narrow angles?

Answer 6

They have the potential to close and reduce the aqueous outflow by blocking the path to trabecular meshwork

Question 7

What is angle closure glaucoma?

Answer 7

Pressure increase due to aqueous buildup

Question 8

How does angle closure glaucoma occur?

Answer 8

Naturally or can be induced by certain medications

Question 9

What is the purpose of the Van Herick technique?

Answer 9

To assess the depth and openness of the anterior chamber and anterior chamber angle and determine if the patient is at risk of angle closure

Question 10

How is the van herick technique assessed?

Answer 10

By comparing the thickness of the cornea to the depth of the peripheral anterior angle chamber

Question 11

Angle, mag, and beam for van herick technique?

Answer 11

-60 degrees
-medium mag (~16x)
-optic section and full height

Question 12

Where do you focus the beam when performing van herick?

Answer 12

On the cornea at the edge of the limbus on both nasal and temporal side

Question 13

Grade 1 van herick

Answer 13

< 1:4

Question 14

Grade 2 van herick

Answer 14

1:4

Question 15

Grade 3 van herick:

Answer 15

1:2

Question 16

Grade 4 van herick:

Answer 16

1:1 or > 1:1

Question 17

How does the anterior chamber appear normally?

Answer 17

Dark and quiet (empty)

Question 18

What can be seen in the anterior chamber during light scatter?

Answer 18

-abnormal white blood cells
-pigment and protein

Question 19

How do white blood cells appear in anterior chamber?

Answer 19

Small white/grey dots

Question 20

How do proteins appear in the anterior chamber?

Answer 20

Haze

Question 21

How do red blood cells appear in the anterior chamber?

Answer 21

Red/brown dots

Question 22

How does pigment appear in anterior chamber?

Answer 22

Brown dots

Question 23

Angle, mag, illumination, and beam for anterior chamber eval:

Answer 23

-30-45 degrees
-high mag (25x or 40x)
-full illumination
-2-3mm parallel-piped or conical beam

Question 24

How to perform anterior chamber evaluation after setup?

Answer 24

-place beam within the pupil focusing on cornea
-push lamp to focus on the anterior lens surface
-pull back to focus halfway between cornea and lens
-scan and evaluate

Question 25

How to prevent reflection during anterior chamber evaluation?

Answer 25

Adjust your beam to fit within the pupil

Question 26

Where should the light beam NOT touch during anterior chamber evaluation?

Answer 26

-corneal reflex -iris -lenticular reflex

Question 27

Grade 0 cells and flare:

Answer 27

No cells and no flare

Question 28

Trace cells and flare grading:

Answer 28

-1-5 cells per field -no flare

Question 29

Grade 1+ cells and flare:

Answer 29

-6-15 cells -faint flare

Question 30

Grade 2+ cells and flare:

Answer 30

-16-25 cells -moderate flare, lens and iris clear

Question 31

Grade 3+ cells and flare:

Answer 31

-26-50 cells -marked flare, iris and lens hazy

Question 32

Grade 4+ cells and flare:

Answer 32

-50+ cells -intense flare, fixed coagulation (no movement)

Question 33

What is the purpose of the indirect illumination test?

Answer 33

To exam the cornea with indirect light

Question 34

What is indirect illumination useful for?

Answer 34

-corneal infiltrates -corneal scars -fine corneal neovascularization -corneal deposits

Question 35

What is the method of indirect illumination?

Answer 35

The object/area being viewed is lit indirectly by reflections or scatter from the adjacent beam

Question 36

Angle, mag, and beam for indirect illumination

Answer 36

-45-60 degrees -medium mag -2-4mm parallelpiped

Question 37

How to perform indirect illumination:

Answer 37

-move slit lamp to area you want to examine -move slit beam out of click stop to focus beam next to the area

Question 38

What is the purpose of sclerotic scatter?

Answer 38

To evaluate the cornea for opacities and irregularities using internal reflection

Question 39

What is sclerotic scattering used for?

Answer 39

Viewing corneal scars and other defects

Question 40

How does a normal cornea appear during sclerotic scatter?

Answer 40

Dark

Question 41

Angle, mag, and beam for sclerotic scatter

Answer 41

-45 degrees -low mag -narrow parallelpiped

Question 42

How to perform sclerotic scattering:

Answer 42

-focus the beam at the temporal limbus and look for a halo of light to form on the nasal limbus -observe cornea to look for haze or opacities

Question 43

What is retroillumination?

Answer 43

When light is reflected off the most posterior structure providing a backlit effect to observe anterior structures

Question 44

What are the two types of retroilluminatin?

Answer 44

Direct and indirect

Question 45

What is retroilluminatin useful for?

Answer 45

-subtle corneal opacities -> scars, neovascularization -lens opacities -iris transillumination defects

Question 46

Steps to direct retroillumination:

Answer 46

-low mag and parallelpiped with 45-60 degrees angle -focus on what you want to observe -move the light beam out of click to reflect light off the surface of the iris and illuminate the area from behind

Question 47

Steps to indirect retroillumination:

Answer 47

-move light beam out of click to reflect the incident beam off the surface of the iris and illuminate the area you want to observe from behind -the area observed is NOT in the direct pathway of the reflected light

Question 48

How is retroillumination performed off of the retina?

Answer 48

-low-med mag -coaxial beam or just off coaxial -beam height that fits directly in pupil (dilated pt) -you will observe a bright orange reflex off the retina

Question 49

What is the purpose of specular \ reflection?

Answer 49

To examine the corneal endothelium or crystalline lens

Question 50

When does specular reflection occur?

Answer 50

When the angle of incidence and the angle of reflection os the slit lamp beam are equal

Question 51

How to perform specular reflection:

Answer 51

-low mag using medium parallelpiped - focus on cornea 30-45 degrees -adjust slit lamp or change beam until beam split intersects with the corneal reflex -increase mag to high -sharply focus the slit lamp on endothelium and observe

Question 52

What is fuch’s endothelial dystrophy?

Answer 52

-loss of corneal endothelial cells -formation of gutatta -> accumulations of collagen on descemets membrane where endothelial cells are gone

Question 53

Purpose of everting eyelids:

Answer 53

To examine the palpebral conj of upper eyelid

Question 54

When to evert upper lids:

Answer 54

-contact lens wearers -red eye -foreign body

Question 55

How to record finding of palpebral conj:

Answer 55

Normal, or pink and quiet -> DONT need to specify that eyelid was everted