Quantitative characterization of types 1 and 2 macular neovascularization in neovascular age-related macular degeneration with intravitreal conbercept: an analysis utilizing optical coherence tomography angiography

AIM: To quantitatively assess central macular thickness (CMT), macular neovascularization (MNV) area, vascular tortuosity (VT), and vascular dispersion (VDisp) in neovascular age-related macular degeneration (nAMD), type 1 and type 2 MNV, by means of optical coherence tomography (OCT) and OCT angiography (OCTA) techniques. METHODS: In this retrospective and observational case series, patients were classified into type 1 or type 2 MNV groups. A comprehensive panel of OCT and OCTA metrics was evaluated, including CMT, MNV area, VT, and VDisp. All subjects underwent a standardized intravitreal conbercept (IVC) regimen [3+pro re nata (PRN)] with a 12-month follow-up. MNV area was obtained by manual measurements with OCTA software, and VT and VDisp were calculated by automated analysis with Image J software. RESULTS: A total of 101 participants were included, with 51 patients in the type 1 MNV group (mean age 67.32±9.12y) and 50 patients in the type 2 MNV group (mean age 64.74±5.21y). The mean number of IVC injections was 3.98±1.53 for type 1 MNV and 3.73±0.81 for type 2 MNV. Both subtypes exhibited significant improvements in visual acuity, accompanied by marked reductions in CMT and MNV area (P<0.05) at 12mo after treatment. In type 2 MNV, VT significantly decreased (P<0.05), whereas no significant change was observed in VT for type 1 MNV. VDisp did not significantly changed in either sybtypes. Moreover, in type 1 MNV, final best-corrected visual acuity (BCVA) using logMAR correlated positively with both pre- and post-treatment CMT, while in type 2 MNV, a significant positive correlation was found between the number of injections and final CMT. CONCLUSION: This study shows that conbercept treatment significantly improves visual acuity and macular structure in both type 1 and type 2 MNV with reductions in CMT and MNV area. The significant reduction in VT in type 2 MNV suggests its potential as a biomarker for disease activity. The findings imply the quantitative assessment useful for the stratification, prognostication, and personalized management of MNV in nAMD.