Right-angled vessels in macular telangiectasia type 2

Abstract

PurposeTo evaluate the role of right-angled vessels (RAVs) during disease progression in macular telangiectasia type 2 (MacTel).MethodsIn this study, 100 eyes of 52 patients and 52 eyes of 26 age-related controls were examined using fundus photography, spectral-domain optical coherence tomography (SD-OCT), OCT angiography (OCT-A) and fundus fluorescein angiography (FFA). Two masked readers graded fundus photographs of patients’ eyes into five disease stages according to Gass and Blodi, and evaluated all eyes for the presence of RAVs. If RAVs were present, their course and origin (arterial vs venous) was evaluated with OCT-A and FFA, respectively. Additionally, we looked for morphological correlates of these vessels on SD-OCT scans. Neovascular eyes were analysed for the presence of RAVs and for morphological changes on formation of neovascularisations (NVs).ResultsIn OCT-A, RAVs were already detectable in eyes with early stages (1 to 2), could be tracked from superficial to outer retinal layers and were shown to form anastomoses in the outer retina with disease progression. These vessels were of both arterial and venous origin as shown by early phase FFA. Dilated capillaries and RAVs in OCT-A corresponded to hyper-reflective alterations of the outer retina on SD-OCT scans. In 19/19 eyes, NVs were associated with the presence of RAVs, and RAVs were shown to directly connect to neovascular complexes and to undergo morphological changes upon NV formation.ConclusionsThe results emphasise the role of RAVs during disease progression from an early stage on and demonstrate their involvement in the development of secondary NVs in MacTel.

Functional Relevance of Hyper-Reflectivity in Macular Telangiectasia Type 2

“…The latter include pigmentary changes, possibly deriving from migrating RPEcells, neurodegenerative processes, cellular debris, and vascular alterations. [21][22][23] Although a correlation of hyperreflectivity with disease progression has been proposed, its functional relevance has yet not been evaluated. In this study, we used an approach that quantified hyperreflective changes in MacTel.…”

Optical coherence tomographic features of macular telangiectasia type 2: Korean Macular Telangiectasia Type 2 Study—Report No. 1

“…We could commonly find clustered HF at the foveola in eyes with only an inner retinal hyporeflective cavity. HF could be related to various causes or signs in MacTel type 2 2 , 12 – 15 . Baumüller et al 12 suggested that HF might represent an early sign of a neurodegenerative process.…”

Quantification of Retinal and Choriocapillaris Perfusion in Different Stages of Macular Telangiectasia Type 2

“…[36][37][38][39] In a recent qualitative analysis, we showed an increase of flow voids and irregular appearance of the choriocapillaris in eyes with advanced (but non-proliferative) disease stages. 36 In this study, we quantified these changes and found an overall reduced and more irregular perfusion of the choriocapillaris indicated by a significant increase of flow voids and reduced kurtosis of signal intensity distribution. Notably, these findings were already observed in early disease stages, indicating an earlier affection of the choroid than previously expected.…”

“…In line with recent findings, 12,35 we observed the presence of pathologic vascular structures in the avascular layer of eyes with advanced and neovascular disease stages, but not in early stages. Though different studies proposed a descent of vascular changes to the outer retina, 12,35,36 segmentation of retinal layers in eyes with advanced disease stages may be challenging, and a collapse of retinal layers due to increasing atrophy may at least in part be responsible for the observed phenomenon.…”