Macula Retinal Imaging Flashcards
What does red-free photography give a better view of?
Vasculature
How can you reduce a small pupil artefact on fundus photography?
Lights off
Allow time to redilate between eyes
Adjust alignment/fixation
Dilate
How can you reduce an exposure artefact on fundus photography?
Adjust flash accordingly
Adjust image brightness accordingly
How can you reduce an opacity/fixation/focus artefact on fundus photography?
Give clear instructions
Use different fixation target
Dilate
What does an OCT A-scan measure?
Depth/reflectivity at one location
1D
What does an OCT B-scan measure?
Forms cross-sectional image from A-scans
2D
What does an OCT C-scan measure?
Combines B-scans to give cube scan
3D
Why can false colour be helpful on OCT scans?
Shows up thin/faint structures
What is god about greyscale viewing of OCT scans?
Easy to identify retinal layers
What are the retinal layers?
ILM
NFL
GCL
IPL
INL
ONL
OPL
OLM
PR IS
PR OS
RPE
What can a cataract cause on OCT?
Shadows
What can myopia cause on OCT?
Curved scan
What do floaters look like on OCT?
Hyperreflective in vitreous
What does a posterior hyaloid look like on OCT?
Hyperreflective line above retina
What do exudates look like on OCT?
Near vessels
Hyperreflective
Shadow underneath
Higher than RPE
What do drusen look like on OCT?
Local RPE elevation
May push RPE up
What conditions are exudates associated with?
Wet AMD
Diab/hypertensive retinopathy
What conditions are drusen associated with?
AMD
Retinal degeneration
Aging
What does active choroidal neovasc look like on OCT?
Hyper reflective mass (new vessels) which can be entangled with RPE
Oedema adjacent
What does inactive choroidal neovasc look like on OCT?
Hyper reflective mass
No oedema
Poss atrophy
What does atrophy look like on OCT?
Reduced RPE reflectivity
Window defect (choroid and sclera brighter)
What causes atrophy?
PR death
(dry AMD, trauma)
What are the types of pigment epithelial detachment (PED)?
Drusenoid
Serous
Fibrovascular
What does drusenoid PED look like on OCT?
RPE and drusen separation (due to osmotic pressure)
RPE irregular
Confluent drusen
What does serous PED look like on OCT?
Dome shaped oedema due to fluid leakage (usually from choroid)
RPE detachment
Optically clear
What does fibrovascular PED look like on OCT?
Dome shaped oedema with neovasc membrane
RPE detachment
Not optically clear
What causes a macular hole?
Vitreo-macular traction during PVD when strong foveal attachment present
What is an epiretinal membrane and what does it look like on OCT?
Thickening of anterior membrane
Hyperreflective membrane
