Purpose:
To investigate tissue optical properties in retinal layers ofpatients diagnosed with type 2 idiopathic macular telangiectasia(MacTel type 2) using spectral domain optical coherence tomography(SD OCT).
Methods:
Forty three patients diagnosed with MacTel type 2 and 15 age-matchedcontrols were enrolled in a cross-sectional case-control study.Tomographic SD-OCT and topographic scanning laser ophthalmoscope(SLO) images were simultaneously recorded (Spectralis HRA+OCT,Heidelberg Engineering, Germany). Yielded OCT data sets wereanalysed using incorporated software that automatically mapsthe magnitude of backreflected light to false-color or grey-scalecross-sectional images in a non-linear characteristic.
Results:
Higher tissue optical properties were detected in the neurosensoryretina of MacTel type 2 patients using the SD OCT compared tothe control group. The hyperreflectivity was most prominentin the outer plexiform layer, the inner plexiform layer andthe nerve fibre layer and focal in the ganglion cell layer,the inner nuclear layer and the outer nuclear layer. The phenomenonwas confined to the parafoveolar region. It was present in angiographicallyseemingly unaffected areas. The degree of hyperreflectivitydecreased or the phenomenon disappeared entirely following theintravitral injection of ranibizumab in 10 (n=10) eyes.
Conclusions:
The SD OCT detected an active disease process before MacTeltype 2 manifested by classical angiographic clinical signs,which may help to indentify early disease stages and affectedfamily members. We assume that this phenomenon represents earlylow-grade edema in the inner retinal layers.
Keywords: optical properties • retinal degenerations: hereditary • imaging/image analysis: clinical