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Michel Paques, Concetta Iole Li Calzi, Kiyoko Gocho, Celine Chaumette, Mustapha Benchaboune, martine ullern, Florian Sennlaub; Time-lapse imaging of dry age-related macular degeneration using adaptive optics: insights into cell kinetics. Invest. Ophthalmol. Vis. Sci. 201657(12):.
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© ARVO (1962-2015); The Authors (2016-present)
During dry age-related macular degeneration (ARMD), photoreceptor loss is temporally and spatially correlated with the disruption of the retinal pigment epithelium monolayer and is accompanied by extensive redistribution of melanin. Here, we used time-lapse FIAO imaging to explore the short-term progression of atrophy and the kinetics of the redistribution of melanin clumps in dry ARMD patients.
The cohort comprised 8 eyes of 6 patients (age, 68 to 74 years; VA, counting fingers to 20/20). Five eyes had foveal sparing, 2 had small parafoveal atrophic spots, and one had extensive atrophy involving the fovea. Margins of atrophic areas closest to the fovea were iteratively imaged by FIAO imaging (rtx1™; Imagine Eyes, Orsay, France; average image field, 1.2mm x 1.2mm; Intervals between imaging sessions 1.2 to 10.2 days; follow-up 10 to 205 days). Progression of atrophy and motion of melanin clumps were analyzed on time-lapse videosequences.
During follow-up, measurable progression was observed in 6 eyes, ranging from 8 to 12μm/month, with significant local variations. Subretinal circulation of melanin clumps was observed in the subretinal space (n=3) and in atrophic areas (n=6). Their size ranged from 5 to 25µm and their velocity peaked at ≈30μm/month. Melanin clumps were also seen to agregate and deagregate. While melanin clumps distant from margins showed erratic, spatially restricted motion, some marginal melanin clumps were apparently moving ahead of and in synchrony with atrophy progression.
Time-lapse FIAO imaging allows short-term documentation of ARMD progression and reveals a complex kinetics of melanin clumps suggesting cellular migration. Recent histology data (Zanzottera et al. IOVS 2015) suggests that most melanin clumps seen by FIAO are intracellular. Therefore, our working hypothesis concerning the coordinated displacement of melanin clumps ahead of atrophy progression is that they correspond to marginal melanin-loaded cells involved in ARMD progression. Determining the epithelial or macrophagic nature of pigmented cells in lesional margins may therefore be important for the understanding of ARMD.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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