Coloboma Simulator | Optic Fissure Defect Vision Tool

Base color

Coloboma type & settings

Coloboma type

Severity100%

Perceptual severity curve Multi-pass deep Visual field scotoma

Image simulation

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

Research notes

Coloboma is a congenital defect caused by failure of the optic fissure to close during the 5th–7th week of gestation. The resulting tissue gap in the inferior nasal quadrant affects the iris, ciliary body, retina, choroid and/or optic nerve. Chorioretinal coloboma produces an inferior visual field scotoma; optic nerve coloboma causes enlarged blind spot and potential central VA reduction. The field loss checkbox overlays a scotoma region using a Gaussian edge blended inferior darkening gradient.

Swatches — Reference vs Coloboma

Reference

HEX: — • RGB: — • xy: —

Coloboma

HEX: — • RGB: — • xy: —

ΔE (CIE76)

—

ΔE (CIEDE2000)

—

Deep preview

Reference

Simulated

Chromaticity (CIE xy)

Colobomatous scotoma axis (toward D65)

D65 white point: 0.313, 0.329

Image simulation

Simulations operate in linear sRGB. Iris coloboma applies a keyhole inferior transparency to the iris aperture zone; chorioretinal mode overlays a graduated inferior visual field scotoma (Gaussian-edge dark region, centred lower half of image field); optic nerve mode adds an enlarged blind spot scotoma plus inferior arcuate shadowing. The visual field loss checkbox applies the scotoma layer globally. ΔE2000 measures shift in the preserved zone.

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 colour swatches are shown.

Advanced mode

Severity curve

Curve param

Channel weights (R,G,B)

Clinical notes: Coloboma produces no primary chromatic impairment; the affected tissue is simply absent (scotoma). Channel weights are neutral (1,1,1). Scotoma ΔE metrics reflect the perceptual distance introduced by darkening in the affected inferior field zone. Colour vision is fully preserved in the retained retina.

Model assumptions & limits

Scotoma is modelled as a uniform inferior darkening with Gaussian edge; real colobomatous field defects have precise boundaries matching the tissue absence extent — usually inferior and inferonasal.
Iris coloboma keyhole effect is cosmetic in the swatch view; real iris coloboma affects depth of field and introduces mild off-axis light entry.
ΔE and chromaticity measures depend on display calibration and ambient illumination.