I85PREP
⌘ K
OCT-C study materials
OCT-C study resources

OCT-C: Recognition of Retinal, Vitreous and Choroidal Pathology on OCT

OCT-C · Work through your exam, one topic at a time.

All guide sections

Recognition of Retinal, Vitreous and Choroidal Pathology on OCT

Localise by compartment

Ask where the abnormality sits relative to the RPE - this single question resolves most questions.

  • Intraretinal: cystoid spaces (macular oedema from any cause), intraretinal fluid, hard exudates (hyperreflective with shadowing), cotton-wool spots, intraretinal haemorrhage.
  • Subretinal: subretinal fluid (optically empty, dome-shaped), type 2 CNV, subretinal drusenoid deposits (reticular pseudodrusen) sitting above the RPE.
  • Sub-RPE: drusen (dome-shaped RPE elevation, intact overlying layers), pigment epithelial detachment - serous (homogeneous, hyporeflective), fibrovascular (irregular, hyperreflective contents), drusenoid (heterogeneous, often with overlying EZ loss). Type 1 CNV is sub-RPE.

Vitreoretinal interface

Epiretinal membrane is a hyperreflective line on the ILM with retinal corrugation and loss of the foveal dip; vitreomacular traction shows a partially detached hyaloid with focal traction and often cystoid change; a full-thickness macular hole shows a gap with cystic, elevated edges and operculum. Lamellar holes spare the outer retina.

Degeneration, choroid and detachment

Outer retinal atrophy shows ELM/EZ loss and RPE attenuation; geographic atrophy shows RPE loss with hyperreflective choroidal visibility. Pachychoroid shows a thickened choroid with dilated Haller vessels and a thinned choriocapillaris, often with shallow subretinal fluid in central serous chorioretinopathy. Choroidal naevi and melanomas thicken the choroid and may show a dome shape, subretinal fluid and compression of overlying structures. Rhegmatogenous detachment shows a corrugated, detached retina with subretinal fluid.

Traps: calling reticular pseudodrusen soft drusen (they sit above the RPE and give a saw-tooth EZ); calling a serous PED a fibrovascular one; mistaking vessel shadowing for intraretinal fluid; ignoring EZ integrity when predicting visual outcome.

Rule of thumb: sub-RPE = PED or type 1 CNV; subretinal = fluid, type 2 CNV or SDrD; intraretinal = oedema, exudate or type 3 neovascularisation.