Predictive multi-imaging biomarkers relevant for visual acuity in idiopathic macular telangiectasis type 1

Abstract

Background: To evaluate the structural changes associated with visual acuity (VA) in patients with idiopathic macular telangiectasia (MT) type 1 using multimodal imaging modalities.

Methods: A retrospective study of 14 patients with MT type 1 and of 10 eyes from 10 healthy individuals as age-matched controls was conducted. The medical records of patients who had undergone colour fundus photography, spectral domain optical coherence tomography (OCT), fluorescein angiography and OCT angiography were reviewed. Central macular thickness (CMT), the areas of macular oedema and ellipsoid zone (EZ) disruption, EZ length, disorganization of the retinal inner layers (DRIL) and external limiting membrane (ELM) disruption, as measured by spectral domain OCT; and vascular density and the foveal avascular zones (FAZ) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP), as measured by OCT angiography, were assessed in MT type 1 eyes and correlated with VA.

Results: The mean baseline best-corrected VA of MT type 1 eyes was 0.45 ± 0.28. The mean CMT was 385.19 ± 75.21 μm in MT type 1 eyes and 252.43 ± 15.77 μm in contralateral eyes (Z = - 4.113, p < 0.001). The mean vessel density of the DCP was lower in MT type 1 eyes (47.25 ± 4.69%) than in contralateral eyes (53.93 ± 2.94%) and normal eyes (59.37 ± 2.50%) (Z = - 3.492, - 4.099; p < 0.001, < 0.001). The baseline logMAR VA was correlated with CMT (r = 0.682, p = 0.007), SCP density (r = - 0.652, p = 0.012), DCP density (r = - 0.700, p = 0.005), total area of EZ disruption (r = 0.649, p = 0.012); and total lengths of EZ (r = 0.681, p = 0.007), ELM (r = 0.699, p = 0.005) and DRIL (r = 0.707, p = 0.005) disruption in the 1-mm-diameter foveal region in MT type 1 eyes.

Conclusions: Decreased DCP density and the presence of DRIL may be predictive biomarkers of VA in MT type 1. CMT, SCP density, total area of EZ disruption, and lengths of EZ and ELM disruption within the 1-mm-diameter central region were strongly associated with VA.

Keywords: Disorganization of the retinal inner layers; Ellipsoid zone disruption; Macular telangiectasia type 1; Optical coherence tomography angiography.

Fig. 1

Comparisons among idiopathic macular telangiectasia (MT) type 1 eyes, contralateral eyes and normal eyes. (a) Central macular thickness (CMT). (b) Density of the superficial capillary plexus (SCP). (c) Density of the deep capillary plexus (DCP). (d) Foveal avascular zone (FAZ) area of the SCP. (e) FAZ area of the DCP. *p < 0.05, ** p < 0.01, *** p < 0.001

Fig. 2

Imaging of the right eye of Patient 4. Capillary variations are visible from the inner to the outer plexiform layers on the temporal side of the macula. (a) Blue arrow shows sparse micro-aneurysms. (b) Fluorescein angiography (FA) reveals hyperfluorescence from micro-aneurysms on the temporal side of the macula during the early stage of MT type 1. (c) FA showing leakage of fluorescein due to vascular endothelial cell injury during the late stage of MT type 1. (d) No lesion is visible in the inner and outer segment junction (IS/OS) and blue-dotted oval shows sparse micro-aneurysms on en-face OCT. (e) OCT angiography (OCTA) reveals decreased capillary density in the superficial capillary plexus. (f) OCTA image showing the transformational foveal avascular zone (FAZ), aneurysms, and telangiectasia in the deep capillary plexus (DCP) on the temporal side of the macula. (g and h) OCTA images show no changes in the outer or choroidal layers, respectively. (i) SD-OCT shows areas of hyper-reflectance from the inner to the outer plexiform layers on the temporal side. (j) OCTA showing blood flow