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
How are visual field defects typically in low tension glaucoma vs primary open angle glaucoma (2)?
Deeper and more central (often foveal threat)
What must be done for low tension glaucoma?
Must do a diurnal IOP curve
What is the likely cause of low tension glaucoma?
Vascular cause
If there is a mild loss in low tension glaucoma, what is the management?
Monitor 3 monthly for one year, then yearly
Are beta-blockers ideal for low tension glaucoma?
No, dont use them
Can you have low tension glaucoma with an IOP of >21mmHg?
No, low tension glaucoma can never have IOP >21, it must be <22mmHg
When assessing the posterior pole for glaucoma, what are three things that can affect VF or NRR/RNFL to look like glaucoma?
Gongenital ON anomalies
Vascular conditions at the ON or RNFL
Tumours or masses along the RNFL
List three congenital ON anomalies that can look like glaucoma. How do these affect VF and in what region? Appearance-wise (and with OCT) is it ambiguous or unambiguous for a non-glaucoma cause?
Tilted disc
ON drusen
ON pit/coloboma
These can give VF defects in the arcuate region, similar to glaucoma
The disc appearance & OCT is unambiguous for a non-glaucoma cause
List two vascular causes that can look like glaucoma. What VF defects do they involve and what appearance can the disc have? What technique can find these causes? What may be needed for management?
Branch retinal vein occlusion
Anterior ischaemic optic neuropathy
Both can give VF defects that involve arcuate regions and a disc appearance for cupping
Cause found with good ophthalmoscopy
OCT may be needed for management
With anterior ischaemic optic neuropathy, distinguish between arteritic and non-arteritic in terms of ONH appearance
Arteritic - cupping
Non-arteritic - no cupping
List 4 key signs for vascular causes that look like glaucoma.
NRR has pallor and/or swollen
APD
CV loss
VA loss
List three RNFL/ON/pathway disruptions that can look like glaucoma (what type specifically). What VF defects do they involve? Do these have fast or slow progression in VF (give numbers)?
Eye tupour or RD (choroidal melanoma)
ON tumour
Pituitary tumour
These can give VF defects consistent with LTG that involve arcuate regions
Shows fast progression Md > 2 dB/yr
What is essential for RNFL/ON/pathway disruptions that can look like glaucoma (any why)? If this is normal, what should be done? What problem does the patient often have? Give four key signs.
BIO essential - may be retinal
-if normal, scan anterior pathway
Often have a reading problem
Key signs - optic atrophy, RAPD, VA loss, CV loss
