Anterior Segment OCT

Question 1

When would you use anterior segment OCT?

Answer 1

assessing any abnormalities in cornea, sclera, bulbar, conjunctiva, lens, iris

Question 2

AS-OCT is commonly used to assess _____ and _____ .

Answer 2

anterior chamber depth & angle for risk of closure

Question 3

What does OCT stand for?

Answer 3

ocular coherence tomography

Question 4

What is coherence?

Answer 4

the quality of forming a unified whole

Question 5

What is tomography?

Answer 5

representation of a cross section through a solid object using x-rays ultrasound, or light

Question 6

What is critical for angle closure suspicion?

Answer 6

identifying iridotrabecular contact (ITC)

Question 7

According AAO, how is angle-closure defined as? (3 categories) What does it relate to?

Answer 7

relates to gonioscopy, IOP, and apparent nerve damage

Primary Angle-Closure Suspect (PACS)
Primary Angle Closure (PAC)
Primary Angle Closure Glaucoma (PACG)

Question 8

If a patient has ≥ 180 degrees of iridotrabecular contact (ITC), normal IOP, no optic nerve damage, how would you assess this?

Answer 8

primary angle-closure suspect (PACS)

Question 8

If a patient has ≥ 180 degrees ITC with peripheral anterior synechiae or elevated IOP, no optic neuropathy, how would you assess this?

Answer 8

primary angle closure (PAC)

Question 9

If a patient has > 180 degrees ITC with PAS, elevated IOP, and optic neuropathy, how would you assess this?

Answer 9

primary angle-closure glaucoma (PACG)

Question 10

What is iridotrabecular contact?

Answer 10

iris appearing to touch the anterior chamber angle at the posterior pigmented TM (or more anterior structures)

Question 11

What are some ways the angle is measured?

Answer 11

AOD — angle opening distance
TIA — trabecular iris angle
TISA — trabecular iris space area
ARA — angle recess area

Question 12

What is trabecular iris angle (TIA)?

Answer 12

triangular area formed from the AOD, the angle recess, and the iris surface, and the inner corneoscleral wall

Question 13

Some practioners use _____ values and compare this to Shaffer system for grading angle widths.

Answer 13

TIA

Question 14

Shaffer system utilized angle widths assessed via ______, not _____.

Answer 14

gonioscopy, OCT

Question 15

What is shallow ACD and narrow angle associated with? (HHHFNSSC)

Answer 15

higher age, female gender, hyperopia, nuclear cataract, small optic disks, short body stature, higher central corneal thickness, chronic angle-closure glaucoma

Question 16

What size central ACD is associated with higher risk of angle closure?

Answer 16

<2.5 mm

Question 17

What is the AS-OCT useful for? (2)

Answer 17

-assessing iris/lens/cornea interaction
- pre and post operative asessment for several surgeries

Question 18

Why is angle closure more common in older patients?

Answer 18

progressive thickening due to aging so lens is more displaced anteriorly –> leading to narrowing the angle

Question 19

What can contribute to narrowing the angle?

Answer 19

aging, and progressive thickening of the lens

Question 20

What is the most common cause of acute primary angle-closure glaucoma?

Answer 20

pupillary block

Question 21

What is plateau iris configuration?

Answer 21

comparatively flat “planar” iris configuration with normal anterior chamber depth

Question 22

Plateau Iris Configuration is more common in what patients?

Answer 22

younger (<50 year olds) female patients w/ hx of angle closure

Question 23

What is lens valut?

Answer 23

perpendicular distance b/w the anterior pole of the lens and the horizontal line joining the 2 scleral spurs on hirozontal scan

Question 24

What does a high lens valut mean?

Answer 24

high risk of closure

Question 25

AS-OCT is very useful pre-and post- operatively for ____, cataract surgery, ______ and more. Especially for procedures which affect the _______.

Answer 25

LPI, ICL; angle morphology