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Tjebo FC Heeren, Traci E Clemons, Marcus Fruttiger, Catherine Egan, Peter Charbel Issa; Macular photoreceptor atrophy defines the end stage of macular telangiectasia type 2. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3138. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
The natural endpoint of macular telangiectasia type 2 (MacTel) has not been explored systematically. The aim of this study was to investigate and describe phenotypic findings in eyes with substantial vision loss due to MacTel, in absence of secondary complications such as neovascular membranes or macular holes.
Eyes with best corrected visual acuity (BCVA) ≤20/200 (≤38 ETDRS letters) were identified from the MacTel Natural History Observation and Registry Study. Fundus colour, fundus autofluorescence, fluorescein angiography and optical coherence tomotraphy images were analyzed. Eyes with evidence of neovascularization or any other pathology leading to severe vision loss other than MacTel were excluded from further analysis.
Out of 3748 eyes of 1875 patients in the MacTel database (November 2017), a total of 196 eyes (5%) had a BCVA ≤20/200. Of those, 78 eyes had a neovascularization, 16 had a full thickness macular hole and 12 eyes had severely reduced visual function unrelated to MacTel (amblyopia, n=7; severe media opacity, n=3;, optic nerve atrophy, n=1; previous retinal detachment, n=1). Mean BCVA of the remaining 90 eyes was 29 letters. 25 eyes had a BCVA ≤20/400, of which 7 eyes had BCVA ≤20/640. Loss of outer nuclear layer (ONL) affecting the fovea and the adjacent temporal area was found in 35% of these 90 eyes. In 65% of the eyes, ONL atrophy involved all other quadrants to variable extent. 66 eyes (73%) had retinal pigmentation. 29% of the eyes with pigmentation and 25% of the eyes without pigmentation had BCVA≤20/400.
An improved understanding of very late disease manifestations may be informative to better describe the natural history MacTel, and help guidance in patient counselling. Fovea-involving photoreceptor atrophy is the morphological correlate for functional loss in MacTel patients with poor visual acuity, and defines the end stage of the disease. This finding will guide a more accurate future disease staging.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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