Abstract
Purpose :
Vascular changes are characteristic for macular telangiectasia type 2 (MacTel type 2). Fluorescein angiographic findings have previously suggested that most vascular changes occur in the superficial and deep capillary plexus of the perifoveal retina.
OCT angiography (OCT-A) allows a differentiated representation of the different retinal layers. The aim of this study was therefore to analyze the spectrum of different vascular changes and to quantify them.
Methods :
15 patients (average age: 65 years) with different stages of MacTel type 2 were examined by OCT-A imaging (Avanti, Optovue). The foveal and parafoveal vascular density as well as the flow areas were analyzed in the superficial and deep capillary plexus and, if visible, in the outer retina. This was done systematically in the ETDRS grid fields of the entire macular area as well as manually in the visibly altered vascular areas. The results were compared with each other and additionally with a normal cohort.
Results :
The analyzed OCT-A images initially showed a reduction and dilation of the deep capillaries temporal to the fovea in the early stage (mean vessel density reduction in deep capillaries 5,78% and mean vessel density reduction in superficial capillaries 3,52%).
In a more advanced stage of disease, similar changes occur in the superficial capillary plexus, but also in the entire perifoveal capillary network. In patients with even further advanced stages, vessels can also be observed in the avascular outer retina. In the course of disease progression, a significant decrease in vascular density both in the superficial as well as in the deep vascular plexus was shown (p-value <0.05).
In addition, differences in the measured values regarding the sectoral parafoveal distribution were detected.
Conclusions :
OCTA angiography, as a new imaging technique, offers the opportunity to differentially visualize and quantify vascular changes non-invasively in retinal vascular diseases such as MacTel type 2. Here, the progressive vascular changes initially occur in the deep capillary vascular network. In the further course of the disease, the changes can additionally be found in the superficial capillary plexus and an enlargement of these areas was analyzed. Both are accompanied by a decrease in vessel density due to vascular reduction and dilatation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.