Does Pattern Recognition on OCT Angiography (OCTA) Help in the Prognosis of Neovascular AMD (nAMD)?

Abstract

Aim:To study the morphological patterns of nAMD on OCTA, compare with ICGA the gold standard and to ascertain whether pattern identification can help in prognosis of the disease and follow up. Materials and Methods:Retrospective study of 103 nAMD patients who visited retina clinic at Chaithanya eye hospital, Trivandrum.Patients who underwent comprehensive fundus evaluation including FFA/ICGA, SD-OCT and OCTA on Heidelberg platform with minimal follow up of 1 year were analyzed. Vascular networks patterns identified on OCTA were analyzed. Area of the lesion on OCTA was correlated with FFA/ICGA at baseline and during treatment. Patients underwent 3 loading anti VEGF injections, followed by PRN on basis of OCT/ICGA findings and the data correlated with OCTA findings. On OCTA, good anatomical outcome was defined as decreased membrane size and decreased/absent SRF during follow up.Results: Network patterns were more discernable on OCTA than ICGA -Sea fan (42%), filamentous (20%), Fish net (17%), ill-defined (13%) and lacy wheel (8%). Out of 8 eyes with ill-defined membranes on ICGA, OCTA revealed fish-net pattern in 2 eyes while 6 remained ill-defined. Size of lesion was comparable between OCTA and ICGA (Mean horizontal and vertical diameters 2621 Vs 2445 and 2535 Vs 2189 μm respectively). Post treatment size of network decreased on OCTA. Good anatomical outcomes were seen in 100% Lacy wheel eyes, 84.6% of sea-fan, 50% of filamentous and 50% of ill-defined pattern eyes. Fish net pattern was resistant to anti-VEGF therapy. Conclusion:OCTA could classify nAMD lesions morphologically into various patterns more clearly and elaborately. Certain morphologies on OCTA had better anatomical outcomes and identification of these at baseline could help in prognostication and patient counseling. OCTA Fish net pattern not described in literature were found to be resistant to Anti-VEGF therapy.