Abstract
Purpose: :
To evaluate OCT as a diagnostic aid in Stargardt's disease and to correlate region specific functional and morphological alterations in patients suffering from Stargardt's disease.
Methods: :
We performed fundus photography, optical coherence tomography (OCT), multifocal ERG (mfERG), static perimetry (Octopus) and autofluorescence (AF) imaging in 5 stargardt patients. Color fundus–, AF– and FA–images were spatially aligned and superimposed. 3–D reconstructions of retinal surface and deeper layers from OCT were spatially matched with fundus images (color, AF, FA). The aligned dataset was subsequently used for comparing region specific changes in the different examination modalities.
Results: :
Stargardt patients show a central retinal atrophy which is characterized by a significant decrease in retinal thickness, assessed with OCT, reduced autofluorescence, reduced amplitudes of mfERG responses and a scotoma as detected with static perimetry. The central atrophic zone is surrounded by a ring of hyperfluorescence, which may show normal light detection thresholds in static perimetry but reduced mfERG amplitudes. 3–D reconstruction of the OCT scans and subsequent alignment to AF images revealed that retinal flecks (diagnostic hallmark of Stargardt's disease), correspond to a thickening of the high reflective outer retinal layer corresponding to the retinal pigment epithelium (RPE). These protuberances of the RPE correspond to areas of high autofluorescence suggesting that accumulation of lipofuscin in the RPE is the anatomical correlate of retinal flecks.
Digital overlay of fundus photographs with AF images revealed that only a subset of retinal flecks show increased autofluorescence, suggesting different populations of flecks, the clinical significance of which remain elusive.
Conclusions: :
Space matching and superimposition of data allow a comparison of Stargardt associated retinal changes for the different examination modalities. Space matched correlation allows to directly assess retinal function in retinal areas that show anatomical alterations. Combination and superimposition of morphological and functional data might facilitate diagnosis in early and unclear cases of Stargardt’s disease.
Keywords: retinal degenerations: hereditary • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)