DIS - Open Angle Glaucoma II - Week 3 Flashcards
Why can drance haemorrhaging occur?
Loss of glial support leads to vascular compromise
Define drance haemorrage.
Any haemorrhage up to 1 DD away from the disc
What can drance haemorrhages precede (2) and by how many years?
Can precede VF and RNFL loss by 2-5 years
What is a very common casue of drance haemorrages?
High systemic blood pressure
Are drance haemorrhages easy to spot or easy to miss?
Easy to miss
What effect does losses in neural tissue have on blood vessels?
they kink
How does PPA occur?
Loss of deep choroidal blood flow gives overlying atrophy
What type of glaucoma is PPA common in?
Low tension glaucoma
What should be noted with gliosis and the B/D/B feature of the RNFL?
Gliosis can give sheen in advanced loss
When assessing B/D/B for RNFL, do you see individual nerves?
no, you see bundles
Which section appears darkest when assessing B/D/B RNFL?
Nasald
What is B/D/B RNFL harder to detect with (3)?
Catarac
Age
High myopia
Can you have localised loss with B/D/B RNFL or only generalised loss?
Yes, you get a wedge loss appearance
What clinical procedure is best for advanced/severe cases of glaucoma?
Visual fields
Must all methods be used for detection? List them (4) and note which is better.
RNFL OCT
Macula GCC OCT
ON appearance OCT/photo
Visual fields
RNFL OCT is better than NRR photos
Describe the following visual field stages by MD and foveal threat:
Mild
Moderate
Advanced
Mild - MD >-6 dB or any central points 15-25 dB
Moderate - MD >-6 dB or any central points 1-15 dB
Severe - MD >-12 dB or one or more central points ≤0 dB
Are clusters of abnormal points by healthy individuals normal in visual field tests? What about a repeated test with the same cluster in the same location ? What is the likelihood of 2 such repeated tests?
A cluster of three abnormal points at any single test is made by 58% normals
1 repeated VF test with a 3 point cluster in the same location is borderline normal (8% normal)
2 repeated VF tests is not found in normals (0%)
If a VF test is abnormal, how long until the repeat VF test?
1 month
AAre VF tests noisy?
Yes
Can VF tests find defects earlier than ON photos?
Yes but only when repeated (earlier 36% of the time)
What can RNFL OCT often give myopes?
Red disease - false positive
What should be used in myopic glaucoma suspects?
VF, mac RGC complex or ON NRR (or both)
What three techniques are best for progresison and change? What is best for moderate/severe cases?
RNFL, ON (NRR), VF
VF is best for moderate/severe cases
Use the SOAP acronym on primary open angle glaucoma:
S (2)
O (4)
A (5)
P (3)
Subjective
-no symptoms, reduced VF
Objective
-nornal ON colour with NRR loss or RNFL defect
-typical VF defect (need x2 baseline for monitoring)
-open unoccluded angle
-IOP >21mmHg at some stage
Assessment
-work out risk
-disc/NFL imaging
-VF
-Gonioscopy
-IOP
Plan
-treat and monitor
-reduce IOP to target - meds and surgery referral