Outer retinal hyperreflective spots on spectral-domain optical coherence tomography in macular telangiectasia type 2

To analyze focal hyperreflective morphologic alterations in outer retinal layers in patients with type 2 idiopathic macular telangiectasia (MacTel type 2) using spectral-domain optical coherence tomography (SD OCT).

Cross-sectional case-control study.

Forty-one patients with MacTel type 2.

Anatomic layers were evaluated and compared with those of controls of similar age. Simultaneous SD OCT scans were obtained with a combined confocal scanning laser ophthalmoscope for simultaneous tomographic and topographic in vivo imaging (Spectralis HRA+OCT; Heidelberg Engineering, Heidelberg, Germany).

Morphologic alterations in the retinal layers secondary to MacTel type 2.

Hyperreflective spots in the outer retina of MacTel type 2 patients were detected in all stages of disease using the SD OCT. Their presence was confined to the foveolar and parafoveolar region. The phenomenon also was detected in a monozygotic twin in an eye with no typical angiographic sign of the disease. A hyperreflective haze was detected in the vicinity of a disruption of the hyperreflective OCT line that is assumed to represent the line between the photoreceptor inner and outer segments and interdigitation of the outer segments and the retinal pigment epithelium. No corresponding pathologic features could be identified by biomicroscopy, time-domain OCT, or confocal scanning laser ophthalmoscope imaging. Crystalline deposits and intraretinal migration of pigmented cells were distinguishable because of differences in shape, reflectivity, and location.

Hyperreflective spots were identified in outer retinal layers of patients with MacTel type 2 in all disease stages. It is suggested that this phenomenon represents an early sign of a neurodegenerative process. Secondary assumptions include extravasated deposits or vascular abnormalities. The pathologic features are indicative of an active disease process before the disease manifests by typical fluorescein angiographic signs.

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