Anterior Segment Imaging

What it does

Anterior Segment Imaging reads the front of the eye from three kinds of input: slit-lamp photographs, anterior-segment OCT (AS-OCT) and corneal tomography maps. The run recognises which kind each upload is and returns the sections that input supports, so one request can carry a slit-lamp photo and a tomography map of the same patient.

From slit-lamp photos it outlines and measures a corneal ulcer or infiltrate, suggests the likely cause (bacterial, fungal, viral or amoebic) and sets a referral urgency; from slit-lamp and retro-illumination photos it types and grades cataract on LOCS III. From tomography maps it separates keratoconus from normal corneas and stages it. From AS-OCT it locates the scleral spur, measures angle opening distance and TISA, and classifies the angle as open or closed.

Intended use

Decision support where the front of the eye is assessed without a cornea or glaucoma specialist at hand. Infectious keratitis is an emergency: GPs and emergency physicians need a fast decision on urgent referral, and the result proposes a referral urgency with the lesion size and likely cause behind it. Cataract grades, keratoconus stages and angle measurements give the specialist a consistent baseline for follow-up.

Who it is for

Emergency physicians and GPs who see red eyes, optometrists, general ophthalmologists, cataract and refractive surgeons screening for keratoconus before laser vision correction, and glaucoma clinics assessing angles. Developers call the run from slit-lamp cameras, tomography software and teleophthalmology services.

Accepted input

• Slit-lamp photos: JPEG, PNG or TIFF exports, or DICOM Ophthalmic Photography objects.
• AS-OCT: DICOM Ophthalmic Tomography objects or vendor exports converted at upload.
• Corneal tomography maps: DICOM Corneal Topography Map objects or the vendor's map export.
• One study is both eyes of one visit; laterality is read from the tag or detected.

Input per section

Section	Input	Why
Infectious keratitis	Slit-lamp photo of the cornea	Ulcer and infiltrate outline and size
Cataract	Slit-lamp or retro-illumination photo of the lens	Nuclear, cortical and posterior subcapsular opacities
Keratoconus	Corneal tomography maps (curvature, elevation, pachymetry)	Staging uses anterior and posterior surfaces and thickness
Angle closure	AS-OCT scan through the angle	Scleral spur, AOD and TISA are measured on the scan

Slit-lamp photos vary widely with illumination technique and camera, and tomography maps are vendor-specific exports; the device is recorded with every result.

Optional context

Symptoms and their duration, contact lens wear, trauma, prior refractive surgery and the clinical question go in clinical_context; contact lens wear and trauma in particular shape the keratitis read. Belin ABCD staging also uses best-corrected distance visual acuity, which only the clinical context can supply.

The result

Section	Content
Infectious keratitis	Ulcer or infiltrate mask and size, likely cause (bacterial, fungal, viral, amoebic), urgent-referral triage
Cataract	Cataract type and LOCS III grade
Keratoconus	Keratoconus versus normal, with stage
Angle closure	Scleral spur location, angle opening distance and TISA, open or closed angle
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 ulcer and infiltrate masks, SR TID 1500 with ophthalmic measurement groups, KOS key images and Encapsulated PDF.
• Cataract: LOCS III (Lens Opacities Classification System III).
• Keratoconus: Belin ABCD staging and the Global Consensus on Keratoconus and Ectatic Diseases.
• Angle: ISGEO classification of angle closure.
• Coding: SNOMED CT and ICD-10/ICD-11 with explicit laterality.