Archive for 2015

The Effect of Light Deprivation in Patients With Stargardt Disease

AUTOSOMAL RECESSIVE STARGARDT DISEASE (STGD1) is the most common inherited juvenile macular degeneration.1 Most patients develop bilateral loss of vision in childhood or early adulthood. This subtype of Stargardt disease is caused by mutations in the ABCA4 gene, which encodes a retina-specific transporter protein (ABCR) in the rims of rod and cone photoreceptor outer segment discs.2–4 Retinal degeneration in ABCA4-linked Stargardt disease is believed to result from the toxic effects of lipofuscin that accumulates in the retinal pigment epithelium (RPE) and the subsequent degeneration of photoreceptors.5

Light can induce photochemical injury at the ocular fundus. Depending on the level and duration of the irradiance, the primary site of damage can be either the photoreceptors or the RPE.6 In ABCA4-linked retinopathies, products generated by the visual cycle accumulate and contribute to retinal damage via both direct toxic effects and increased photosensitivity. A major fluorophore of lipofuscin, bis-retinoid N-retinylidene-N-retinyl-ethanolamine (A2E), accumulates with other, currently unidentified lipofuscin constituents within the RPE.7–9 Thus, an excessive accumulation of A2E has been observed in both Abca4-/- mice and patients with Stargardt disease.5,10 Lipofuscins (and A2E in particular) are potent photosensitizers11–14 that can induce oxidative damage, thereby accelerating light-induced retinal damage and RPE atrophy.14–16 This oxidative damage may affect the rate of disease progression in patients with Stargardt disease…

Full Paper: The Effect of Light Deprivation in Patients With Stargardt Disease
(1.33M PDF)

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