Anterior Segment OCT Flashcards
When would you use anterior segment OCT?
assessing any abnormalities in cornea, sclera, bulbar, conjunctiva, lens, iris
AS-OCT is commonly used to assess _____ and _____ .
anterior chamber depth & angle for risk of closure
What does OCT stand for?
ocular coherence tomography
What is coherence?
the quality of forming a unified whole
What is tomography?
representation of a cross section through a solid object using x-rays ultrasound, or light
What is critical for angle closure suspicion?
identifying iridotrabecular contact (ITC)
According AAO, how is angle-closure defined as? (3 categories) What does it relate to?
relates to gonioscopy, IOP, and apparent nerve damage
Primary Angle-Closure Suspect (PACS)
Primary Angle Closure (PAC)
Primary Angle Closure Glaucoma (PACG)
If a patient has ≥ 180 degrees of iridotrabecular contact (ITC), normal IOP, no optic nerve damage, how would you assess this?
primary angle-closure suspect (PACS)
If a patient has ≥ 180 degrees ITC with peripheral anterior synechiae or elevated IOP, no optic neuropathy, how would you assess this?
primary angle closure (PAC)
If a patient has > 180 degrees ITC with PAS, elevated IOP, and optic neuropathy, how would you assess this?
primary angle-closure glaucoma (PACG)
What is iridotrabecular contact?
iris appearing to touch the anterior chamber angle at the posterior pigmented TM (or more anterior structures)
What are some ways the angle is measured?
AOD — angle opening distance
TIA — trabecular iris angle
TISA — trabecular iris space area
ARA — angle recess area
What is trabecular iris angle (TIA)?
triangular area formed from the AOD, the angle recess, and the iris surface, and the inner corneoscleral wall
Some practioners use _____ values and compare this to Shaffer system for grading angle widths.
TIA
Shaffer system utilized angle widths assessed via ______, not _____.
gonioscopy, OCT
What is shallow ACD and narrow angle associated with? (HHHFNSSC)
higher age, female gender, hyperopia, nuclear cataract, small optic disks, short body stature, higher central corneal thickness, chronic angle-closure glaucoma
What size central ACD is associated with higher risk of angle closure?
<2.5 mm
What is the AS-OCT useful for? (2)
-assessing iris/lens/cornea interaction
- pre and post operative asessment for several surgeries
Why is angle closure more common in older patients?
progressive thickening due to aging so lens is more displaced anteriorly –> leading to narrowing the angle
What can contribute to narrowing the angle?
aging, and progressive thickening of the lens
What is the most common cause of acute primary angle-closure glaucoma?
pupillary block
What is plateau iris configuration?
comparatively flat “planar” iris configuration with normal anterior chamber depth
Plateau Iris Configuration is more common in what patients?
younger (<50 year olds) female patients w/ hx of angle closure
What is lens valut?
perpendicular distance b/w the anterior pole of the lens and the horizontal line joining the 2 scleral spurs on hirozontal scan
