week 5 Flashcards
OCT vs FA what do they detect?
OCT: best way to detect changes in thickness
Fluorescein Angiography: only way to detect leakage
list some structures that might appear highly reflective on OCT?
horizontal structures, ERM, CWS, hemes, hard exudates, RPE hyperplasia, drusen, RPE atrophy, CNVM, retinal scars, choroidal nevi
*RPE dropout- this appears bright because there is more light from the retina getting though even though it’s a loss of pigment
what are some structures with low reflectivity?
vertical structures, fluid, cysts or cavities, shadowed areas, “ beneath a detachment ( RD or PED), vitreous
what 3 layers of OCT are hyperreflective?
ILM/ NFL and RPE are hyper-reflective
Band 1=
ELM- band slightly lighter in color than ONL
Band 2=
IS/OS- inner segment/outer segment junction- light band
Band 3=
outer segment tip= Verhoff’s membrane
Band 4=
RPE, possibly including Bruch’s
Vitreomacular traction puts you at risk for?
Macular hole
RPE contains what 2 types of pigment?
Melanin: does not change much after birth
Lipofuscin: increases with age
what is lipofuscin made of?
mainly derived from chemically modified residues of partially digested photoreceptor outer segments
Only OCT that can do autoFL?
spectralis OCT
Lipofuscin excitation: 300-600 nm
T/F: in the Macular Photocoagulation Study (MPS) study, those who got lasered, ended up with the same vision as the untreated group after 5 years ?
Yes, but it was better bw the 5 years
What were some of the findigns for the Macular Photocoagulation Study (MPS) study in regards to what laser should be used depending on where the CNV was?
- Only use Argon on extrafoveal areas
- For Jutxtafoveal areas use krypton laser (for lesions closer to fovea)
- For subfoveal, IF you do choose to laser, use Krypton
which laser uses less thermal energy, ARgon or krypton?
krypton
What were 4 major risk factors (those who already have CNV in one eye- chance of happening in the fellow eye: ) associated with MPS study?
1) Five or more drusen
2) confluent drusen
3) retinal hyperpigmentation
4) systemic hypertension
Patients with all 4 risk factors =87% chance to develop wet AMD (CNV) in fellow eye within 5 years
-Eyes with none of the risk factors have less than 5% chance to develop in the other eye
WHat steps are taken in photodynamic therapy?
Verteporforin administered as intravenous infusion (aka Visudyne)
- binds to low density lipoprotein (LDL)
- goes to choroid
- absorbed by CNVM
- then apply laser (10 mins after dye has been injected)
- non-thermal infrared laser= no destruction of viable tissue – for no longer than 83 secs
- oxygen free radicals are released
- endothelial damage and thrombus occur
- abnormal vessels occlude
how often did photodynamic therapy have to be repeated
- 1st year: 3-4 treatments
* 2nd year: 2-1 treatments
what are some of the side effects of PDT?
pain associated with infusion= common
Visual disturbances= hallucinations
Photosensitivity reaction: had to be completely covered head to toe after treatment otherwise pts would get very sun-burnt
**Newer findings: PDT found to create “expression” of VEGF reason why repeated treatments are needed
what was the outcome of Complications of Age-related Macular degeneration prevention trial (CAPT)?
Q: should they laser soft drusen? (Lasering drusen thins this aspect of Bruch’s causing increased permeability – goal is to restore normal transport between retina and choroid)
OUTCOME: No diff (nor harm but no benefit) in treating one eye vs untreated fellow eye for loss of 3 lines or more of acuity or progression to advanced AMD
Macugen: cost, freq, why is it no longer first line?
Macugen (Pegaptanib)- breakthrough drug
1st anti-angiogenic drug approved for inhibiting VEGF with CNV formation ~2004
NOT FIRST LINE: Blocks VEGF of a particular isoform (doesn’t target all isoforms)
–Intravitreal injection every 6 weeks for 2 years $$
–Approx. cost of $1,200 per injection
Lucentis vs Avastin:
Lucentis done q3 months then q6 months/2 years (based on the PIER study) OR as needed basis (PRONTO study)
-Approx cost: $2000 per 0.3ml injection
Avastin:
- Larger molecule with a longer ½ life
- Approx cost: $50-150 for 0.3 ml injection
- Much less $$, used once a month
how does elyea compare to lucentis/avastin?
possibly superior to others,
Approx cost: $1,850 per injection, every 2 months
List several possible side effects of intravitreal injections:
endophthalmitis catarcts-traumatic RD-if injection goes too far myocardial infarction IOP spike uveitis
