Retinal OCT

What it does

Retinal OCT reads macular cube and optic nerve head volumes, the core exam of retina and glaucoma clinics. The run flattens and registers the B-scans, finds the fovea and the optic disc to centre the ETDRS grid, and segments the retinal layers and choroid into thickness and volume maps.

On the macula it detects and measures intraretinal fluid, subretinal fluid and pigment epithelial detachment in nanolitres per ETDRS subfield; stages AMD from drusen volume, reticular pseudodrusen, iRORA/cRORA atrophy and signs of macular neovascularisation activity; decides whether diabetic macular oedema is centre-involved from central subfield thickness and reports DME biomarkers; and reads the vitreomacular interface. For glaucoma it compares peripapillary RNFL and macular GCIPL thickness with normative percentiles. With a prior visit, fluid, central subfield thickness, atrophy area and RNFL thickness are reported as change.

Intended use

Decision support for physicians deciding on anti-VEGF injections, referrals and glaucoma follow-up: fluid volumes and thickness values that support treat-and-extend decisions, and a consistent read of AMD, DME and vitreomacular findings with the B-scans that show them.

Who it is for

Retina and glaucoma specialists, general ophthalmologists, residents, and optometrists and diabetes clinics that run OCT in primary eye care. Developers add the run to OCT viewers, injection-clinic software and trial reading centres.

Accepted input

• DICOM: Ophthalmic Tomography, OCT B-scan Volume Analysis and Ophthalmic Thickness Map objects.
• Vendor files: Heidelberg, Zeiss, Topcon and Optovue exports (.e2e, .vol, .fds, .img, .OCT), converted to DICOM on upload.
• Prior visit in prior_files for the change section.

Requirements

Requirement	Why
Macular cube volume	Layers, fluid, AMD, DME, vitreomacular findings and GCIPL
Peripapillary or ONH scan	RNFL quadrant and clock-hour thickness
Device manufacturer and model	Layer thickness and normative values are device-specific
Scan protocol (volume size, B-scan count)	Correct ETDRS grid placement and volume calculation
Laterality (tag or detected)	Every finding is reported per eye (OD/OS)

Signal strength, decentration, blinks and motion are checked first; a scan below the quality gate is reported as such.

Optional context

Diagnosis and treatment history (anti-VEGF injections and dates), diabetes, myopia and the clinical question go in clinical_context; high myopia matters because it changes layer thickness.

The result

Section	Content
Retinal layers and thickness	Layer and choroid boundaries, thickness and volume maps on the ETDRS grid
Retinal fluid	IRF, SRF and PED detection with volumes (nL) per ETDRS subfield
Age-related macular degeneration	Drusen volume, reticular pseudodrusen, iRORA/cRORA, MNV activity, AMD stage
Diabetic macular oedema	Centre-involved DME yes or no, central subfield thickness, DRIL, hyperreflective foci, SRF
Vitreomacular interface	Epiretinal membrane, vitreomacular traction, macular hole with minimum diameter
Glaucoma (RNFL and GCIPL)	RNFL by quadrant and clock hour, GCIPL thickness, normative percentiles, glaucoma likelihood
Change since prior visit	Change in fluid, central subfield thickness, atrophy area and RNFL thickness
Draft report	Opt-in (options.report): an English narrative that interprets the result for the reader (findings, impression, limitations); every number is checked against the findings

Standards

• DICOM: SEG for layers and fluid; Ophthalmic Thickness Map; SR TID 2100 Macular Grid Thickness and Volume Report for the nine ETDRS subfields; SR TID 1500 with TID 2120 and TID 2127; surfaces coded with CID 4273.
• Lexicon and definitions: IN•OCT consensus lexicon (Staurenghi 2014), CONAN nomenclature for neovascular AMD (Spaide 2020), CAM iRORA/cRORA definitions (Sadda 2018), Beckman stage.
• DME: DRCR.net centre-involved DME thresholds, which are device- and sex-specific, on ETDRS central subfield thickness.
• Vitreomacular: IVMTS classification (Duker 2013).
• Glaucoma: ISNT rule and normative colour coding.