01 Anterior Chamber

What is a diffuse direct beam used for?

Use to illuminate and observe large gross areas of the eye

_______ beam is used on low magnification and is not focused on any structure.

Diffuse direct

What are the 2 types of direct illumination?

-Parallelpiped

-Optic section

Parallelpiped and optic section are performed at _______° angle displacement.

45-60°

What magnification, illumination, and width/height beam settings do we use with parallelpiped?

-Low to moderate magnification (10-16x)

-Low to moderate illumination

-2mm beam width

-Full beam height

What magnification, illumination, and width/height beam settings do we use with optic section?

-Moderate magnification (16x)

-Moderate illumination

-Narrowest width possible

-Full beam height

True or False: Optic section allows us to determine the numerical thickness of the cornea.

False

What can the van Herick method be used for?

estimate anterior chamber angle

What must the angle displacement be when performing the van Herick technique?

60°

We want the anterior chamber to be at least _____ of the corneal thickness.

1/4

When assessing the anterior chamber angle using the van Herick method, what are the ratios for Grades 4, 3, 2, 1, and 0?

-Grade 4 is 1 : 1 ratio

-Grade 3 is 1 : 1/2 ratio

-Grade 2 is 1 : 1/4 ratio

-Grade 1 is 1 :

When using the van Herick method, if the width of the chamber interval is greater than the width of the corneal optic section, what is the Grade of the anterior chamber angle?

Grade 4

When using the van Herick method, if the width of the chamber interval is 1/4 to 1/2 width of the corneal optic section, what is the Grade of the anterior chamber angle?

Grade 3

When using the van Herick method, if the width of the chamber interval is 1/4 width of the corneal optic section, what is the Grade of the anterior chamber angle?

Grade 2

When using the van Herick method, if the width of the chamber interval is less than 1/4 width of the corneal optic section, what is the Grade of the anterior chamber angle?

Grade 1

When using the van Herick method, if you only see the width of the corneal optic section and no width of the chamber interval, what is the Grade of the anterior chamber angle?

Grade 0

With a Grade ___ anterior chamber angle, the angle is wide open.

4

With a Grade ___ anterior chamber angle, the angle is unlikely to close.

3

With a Grade ___ anterior chamber angle, the angle is narrow and capable of closing.

2

With a Grade ___ anterior chamber angle, the angle is extremely narrow and may close with full pupillary dilation.

1

With a Grade ___ anterior chamber angle, there is no space between the optic section and iris.

0

When using the shadow technique to assess the anterior chamber angle, what is the Grade if there is no shadow?

Grade 4

When using the shadow technique to assess the anterior chamber angle, what is the Grade if more than 2/3 of the iris is illuminated?

Grade 3

When using the shadow technique to assess the anterior chamber angle, what is the Grade if 1/3 to 2/3 of the iris is illuminated?

Grade 2

When using the shadow technique to assess the anterior chamber angle, what is the Grade if less than 1/3 of the iris is illuminated?

Grade 1

What does it mean if we record 4/3 OD and 4/3 OS for depth in the anterior chamber tab?

-In OD, temporal is Grade 4 and nasal is Grade 3

-In OS, nasal is Grade 4 and temporal is Grade 3

*We record is depending on the order in which we encounter the eye (when examining left to right)