Base color

STGD1 onset category & settings

Stargardt onset category

A2E lipofuscin / macular atrophy severity 50%

Perceptual severity curve Multi-pass deep simulation

Image simulation

Choose image Upload JPG/PNG (max 1200 × 1200). See how a scene appears through juvenile Stargardt (rapid foveal cone loss, dense central scotoma, bull's-eye maculopathy), young-adult onset (expanding central scotoma with perifoveal flecks), or late-onset fundus flavimaculatus (slow perimacular yellow-white fleck accumulation with preserved foveal function until 5th–6th decade).

Research notes

ABCA4 as single gene — spectrum of phenotypes: Over 1,200 disease-associated ABCA4 variants have been identified. The allele severity model explains phenotypic heterogeneity: two severe (null/null) alleles → severe cord dystrophy or cone-rod dystrophy; one severe + one moderate → classic juvenile Stargardt; one moderate + one mild → young-adult onset; two mild → late-onset fundus flavimaculatus. The same ABCA4 gene also causes autosomal recessive cone-rod dystrophy (arCRD) when allele severity exceeds the Stargardt threshold. The "dark choroid" sign on fluorescein angiography — blockage of background choroidal fluorescence by excess RPE lipofuscin — is pathognomonic for ABCA4 disease and visible in 80%+ of Stargardt patients.

Swatches

Normal

HEX: — • RGB: — • xy: —

STGD affected

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ΔE (CIE76)

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ΔE (CIEDE2000)

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Deep preview

Normal

STGD (deep)

Chromaticity (CIE xy)

A2E lipofuscin chromaticity shift

D65 white point: 0.313, 0.329

Image simulation

Stargardt disease simulations model the progressive foveal-then-perifoveal cone and RPE degeneration from A2E bisretinoid lipofuscin toxicity in the sRGB colour space. Juvenile STGD1: models rapid foveal cone loss — predominantly central L/M-cone attenuation producing bull's-eye maculopathy with dense central scotoma; Snellen acuity often drops to 6/60 or worse within 5–10 years of onset. Young-adult STGD1: models expanding central scotoma with perifoveal fleck spread — moderate L/M/S-cone attenuation and chroma reduction. Late-onset fundus flavimaculatus: models slow perimacular lipofuscin accumulation with foveal sparing — mild cone signal disruption until late stages. A2E absorption (~430 nm peak) causes a mild warm chromaticity bias in early stages (before RPE death converts the effect to achromatic desaturation). ΔE2000 per Sharma et al. (2005). Not for clinical diagnosis — Stargardt requires FAF imaging, SD-OCT, FFA (dark choroid), and ABCA4 genetic testing.

Multi-condition comparison

Condition A

Condition B

Steps

Compare juvenile Stargardt (severe ABCA4, rapid foveal loss), young-adult onset (moderate alleles, expanding scotoma), and late-onset fundus flavimaculatus (mild alleles, slow perimacular change).

Advanced mode

ABCA4 allele severity

Macular stage

Imaging correlation

Dark choroid on FFA — pathognomonic for ABCA4: Normally, background choroidal fluorescence is visible through the RPE on fluorescein angiography. In Stargardt disease, massively elevated RPE lipofuscin absorbs the 488 nm excitation light before it reaches the choroid, producing a characteristic "dark" or "silent" choroid with the retinal vessels appearing bright against a dark background. This sign is 80–85% sensitive and >95% specific for ABCA4 disease, making it the single most useful clinical differentiator from AMD and other macular atrophies.

Model assumptions & limits

Juvenile STGD1: Models rapid foveal cone degeneration — predominantly central L/M-cone loss with secondary S-cone involvement. The foveal-first pattern reflects the high metabolic demand and A2E generation rate of foveal cones.
A2E warm bias: In early stages, A2E absorption at ~430 nm creates a mild warm yellow-orange bias (reduced S-cone signal). As RPE death progresses, this warm bias is replaced by achromatic desaturation from photoreceptor loss.
Late-onset FFM: Models foveal-sparing peripheral fleck accumulation — cones are relatively preserved even with extensive perifoveal flecking, explaining the paradox of preserved central acuity despite dramatic FAF changes.