7 min read
Reading the OCT macula
Layer-by-layer interpretation of a macular OCT.
Learning objectives
- Identify the major retinal layers on OCT.
- Localize fluid to the correct compartment.
- Separate the common macular pathologies.
1. Foveal contour
Is the normal foveal depression preserved, lost (oedema), or replaced by a bump or hole?
2. Layers
Trace RNFL, GCL, INL, ONL, ellipsoid zone, and RPE. Disruption of the ellipsoid zone correlates with vision.
3. Fluid
Intraretinal (cystoid spaces), subretinal (between retina and RPE), or sub-RPE (PED)? Each points to different disease.
4. RPE and beneath
Look for drusen, PEDs, and hyper-reflective material suggesting neovascular membranes.
Pearls
- Correlate OCT with the fundus photo — they answer different questions.
- Shadowing beneath a hyper-reflective lesion is a useful localizing sign.