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How does glaucoma cause cupping?
loss of RGC-> decrease in rim-> decrease in cup size
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most suspicious CD ratio?
small cup + large CD ration
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What are glaucoma key features?
- thinning of rim- CD ratio change
- ISNT rule
- bv
- NFL
- lamina cribosa
- PPA
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bv changes in glaucoma?
- bayonetting
- shift nasally`
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NFL changes in glaucoma?
- inferotemporal wedge defect is most common
- see striations
- loss of neuroretinal rim-> defects in central fibres
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how much NFL is lost when VF defect appears
40%
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lamina cribosa and glaucoma?
if visible suspicious
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alpha PPA?
hyperpigmentation near the OD
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b PPA?
- complete atrophy down to choriocapillaris
- indicative of glaucoma signs
- more commonly in temporal region
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Murray Fingeret's 5 rules?
- 1. scleral RING: OD size
- 2. size of RIM
- 3. RNFL
- 4. REGION outside the OD: PPA
- 5. RETINAL/OD haemorrhages
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What does end stage damage look like?
- all neural disc tissue is destroyed
- disc white and deep
- atrophy of retinal NF
- striations absent
- bv dark and sharply defined
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IOP diurnal variation and POAG?
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gold standard VF?
- Humphrey
- Central 24-4 FAST SITA
- 54 pts, 6 degrees
- full threshold white on white
- repeat 2: for confirmation of progression
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what percentage is unreliable for VF?
>20%
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VF scotomas with glaucoma?
- relative paracentral scotoma: 10-15
- Seidel scotoma: NFL shape
- Arcuate scotoma
- Nasal step
- Ring scotoma: from arcuate scotoma
- temporal wedge defect
- Hemifield defect
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Characteristics of VF defects and glaucoma?
- localised
- hoz midline
- begin nasal to BS
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Criteria for VF with glaucoma
- 1. >3 non edge pts, depressed >10db
- 2. >3 pts sens p<5% and 1 pt sense p<1%
- 3. PSD at p<5%
- 4. GHT: abnormal field
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SWAP
- blue dots/yellow bg
- early VF loss
- Kcell pathway
- longer testing time, higher variability, affected by cataracts, effectivness???
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DDx optic nerve drusen
- bilateral
- assoc w VF defect
- x glaucoma
- maybe not ONLY be in cup
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DDx tilted disc?
- straight edge inferior
- disc margin indistinct
- more absolute VFD
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DDX coloboma?
- congenital
- inferior
- complete loss of ONH
- assoc scotoma
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DDx congenital optic pit
- various size/location
- greyish white
- assoc macula detachment
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