Base color

Model & settings

Scotoma type

Scotoma severity / density50%

Perceptual severity curve Absolute scotoma Bilateral scotoma (symmetric)

Image simulation

Choose image Upload JPG/PNG (max 1200×1200). Simulated canvas next to original.

Research notes

Scotomas are the canonical visual field defect — present across the entire spectrum of ophthalmic and neuro-ophthalmic disease. The central type simulates the crushing impact of macular disease (AMD, Stargardt, central serous, optic neuritis) on reading and face recognition. The arcuate/Bjerrum type captures glaucoma's characteristic RNFL bundle-territory field loss, which follows the arcuate nerve fibre layer paths from the superior and inferior poles of the optic disc. The ring scotoma simulates mid-peripheral loss with central and peripheral island sparing, as seen in retinitis pigmentosa and advanced glaucoma, where tunnel vision with nasal step and ring defect is the classic VF signature.

Swatches — Reference vs Scotoma Loss

Reference

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Scotoma Sim

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ΔE (CIE76)

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ΔE (CIEDE2000)

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Deep preview

Reference

Simulated

Chromaticity (CIE xy)

Achromatic axis (to D65)

D65 white point: 0.313, 0.329

Image simulation

Simulations operate in linear sRGB for perceptual correctness. ΔE2000 implemented locally. Central scotoma mask: Gaussian falloff from the image centre, modulated by scotoma size (°) and depth (relative = partial luminance reduction; absolute = full zeroing). Arcuate mask: polar-coordinate wedge along the superior and inferior arcuate bundle territories (Bjerrum zone, 10–20° from fixation), using angular sector masking. Ring scotoma: annular Gaussian band with inner (preserved central island) and outer (preserved peripheral) zones. Severity controls scotoma density — at 100%, absolute scotoma zeroes affected field regions. Bilateral mode mirrors the scotoma symmetrically for bilateral disease processes.

Multi-condition comparison

Condition A

Condition B

Steps

Compare normal, Condition A and Condition B across multiple severities. If an image is loaded it will be processed into the grid, otherwise color swatches are shown.

Advanced mode

Scotoma size (diameter °)

Scotoma depth

Eccentricity

Clinical notes: Most patients are unaware of their scotoma (negative scotoma) until loss is severe — the brain fills in missing areas seamlessly. Positive scotomas (perceived dark or colored patches) are more characteristic of photoreceptor loss in macular disease. Reading is critically dependent on the central 5° foveal field — even a 2° central absolute scotoma abolishes the ability to read standard print. The arcuate Bjerrum zone (10–20° from fixation) maps to the most clinically important RNFL bundles superior and inferior to the disc.

Model assumptions & limits

Central scotoma is approximated as a circular Gaussian; real central scotomas follow photoreceptor topography and may be irregularly shaped.
Arcuate scotoma uses a simplified polar wedge; real Bjerrum scotomas are thin (2–5° in height) curved arcs following exact NFL bundle paths.
Ring scotoma assumes symmetric annular loss; real RP ring scotomas are eccentric and irregular, typically worse inferiorly.