Functional Analysis of Retinal Flecks in Stargardt Disease
|Tommaso Verdina1*, Stephen H. Tsang2,3, Vivienne C. Greenstein2, Jana Zernant2, Andrea Sodi1, Luiz H. Lima4, Stanley Chang2, Rando Allikmets2,3 and Ugo Menchini1|
|1 Department of Specialized Surgical Sciences, Eye Clinic, University of Florence, Florence, Italy|
|2 Department of Ophthalmology, Columbia University, New York, NY, USA|
|3 Department of Pathology and Cell Biology, Columbia University, New York, NY, USA|
|4 Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil|
|Corresponding Author :||Tommaso Verdina MD
Department of Specialized Surgical Sciences
Eye Clinic - University of Florence
Largo Brambilla 3, 50134 Florence, Italy
E-mail: [email protected]
|Received June 04, 2012; Accepted July 23, 2012; Published July 30, 2012|
|Citation: Verdina T, Tsang SH, Greenstein VC, Zernant J, Sodi A, et al. (2012) Functional Analysis of Retinal Flecks in Stargardt Disease. J Clin Exp Ophthalmol 3:233. doi:10.4172/2155-9570.1000233|
|Copyright: © 2012 Verdina T, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
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Purpose: To evaluate visual function of flecked areas in a series of patients with Stargardt disease (STGD) and compare them with adjacent non flecked areas.
Methods: Twenty–seven patients with STGD, ABCA4 mutations and yellowish retinal flecks at fundus examination were recruited. Microperimetry with the Nidek MP-1 and fundus autofluorescence imaging (FAF) were performed in all the patients (27 eyes) while spectral-domain optical coherence tomography (SD-OCT) was performed in a subgroup of patients (20 eyes). Visual sensitivity (in dB) for each hyperfluorescent flecked area on FAF was compared with the value of the nearest adjacent non-flecked area in the MP-1 grid and at approximately the same distance from the fovea. Retinal structure in some of the flecked areas tested by microperimetry was analysed with SD-OCT. All patients were screened for mutations in the ABCA4 gene by APEX array and direct sequencing.
Results: A total of 1836 locations (68 locations for each eye with the 10-2 program) were tested with the MP-1 and 97 corresponded to hyperautofluorescent flecks. A repeated measure, linear regression analysis was used to evaluate differences between visual sensitivity associated with the 97 flecked areas with those in the 97 neighbouring non-flecked areas. The difference was statistically significant (p<0.001) (flecked areas 12.89 +/- 3.86 dB vs. nonflecked areas 14.40 +/- 3.53 dB, respectively). SD-OCT in the flecked areas revealed the presence of hyperreflective dome-shaped lesions in the outer retina located at the level of the retinal pigment epithelium (RPE), with dislocation or disruption of the photoreceptor layer.
Conclusions: In STGD hyperfluorescent flecks on FAF are associated with decreased visual sensitivity compared to adjacent non-flecked areas and with an alteration of the photoreceptor layer on OCT. Flecks do not represent only a typical ophthalmoscopic feature but correspond, in some cases, to retinal damage that contributes to patients’ visual loss.