Choroidal changes correlate with type 1 neovascular activity in neovascular age-related macular degeneration and...

To investigate the association among choroidal factors and lesion activity of polypoidal choroidal vasculopathy (PCV) and type I neovascular age-related macular degeneration (nAMD) using swept-source optical coherence tomography angiography (SS-OCTA).

69 eyes with PCV or type I nAMD were retrospectively included. All eyes had either ≥2 consecutive non-exudative visits without treatment or no exudation/treatment within 6-month SS-OCTA follow-up. Lesions were categorised into active and inactive based on progression, defined as exudation, branching vascular network (BVN)/macular neovascularisation enlargement or recurrence/new/growth of polypoidal lesions. Choroidal parameters, including mean choroidal thickness (MCT), choroidal vascularity index (CVI) and choroidal volume (CV), were evaluated before and after lesion progression. The association between CVI variation and lesion area growth in PCV was also analysed.

No baseline differences in MCT or CVI were found between PCV and nAMD. However, significant differences in CVI and MCT variation were observed between active and inactive lesions (p<0.05). In PCV, lesion activity was characterised by decreased CVI and increased MCT, while in nAMD, only MCT and CV increased. Notably, combined CVI decrease and MCT increase served as a sensitive marker for active PCV (p<0.05), but not for nAMD. CVI reduction also correlated with BVN growth in PCV (R=-0.722, p<0.01).

Choroidal parameters varied significantly during lesion progression. Combined CVI decrease and MCT increase sensitively reflected active PCV lesions and were correlated with lesion location, size and progression, highlighting the differences in the choroidal microenvironment in the activities of PCV and nAMD.