To assess the longitudinal development of choroidal neovascularization (CNV) Type 2 after intravitreal anti-vascular endothelial growth factor by optical coherence tomography-angiography (OCT-A).
Five eyes of five patients with naive CNV Type 2 were assessed by OCT-A in this observational longitudinal study. To perform, the OCT-A used an 840-nm wavelength OCT device (XR-Avanti, Freemont; Optovue) based on split-spectrum amplitude-decorrelation angiography algorithm. The timing of analysis was after 24 hours, between 7 days and 10 days, between 12 days and 18 days, and 30 days after the intravitreal anti-vascular endothelial growth factor injections. The protocol of analysis was 3-mm × 3-mm OCT angiograms centered at the macula. The day after the injection, OCT-A showed the decrease of neovascularization, with apparent vessel fragmentation. The CNV area was reduced with pruning of thinner anastomoses and loss of smaller vessels. Decrease of dimensions of CNV area, microvascular rarefaction, and vessels narrowing was observed between 7 days and 10 days, between 12 days and 18 days because of the further loss of smaller capillaries. Residual flow was always visible to the afferent trunk over the time.
The mean age of patients was 72.6 (SD ±16.22) years. All were women, naive cases, and followed from 5 months to 14 months. Over that time, they had a mean number of 5.5 intravitreal injections (from 3 to 8) and a mean number of 11 OCT-A examinations each (from 8 to 26). The most salient result emerging from this study is the consistency in the patterns of cyclic CNV variations after treatment in different patients. This CNV cycle was approximately 62 days long.
This study suggests that OCT-A is able to detect the Type 2 CNV developments. This new method allows noninvasive analysis of CNV networks remodeling during anti-vascular endothelial growth factor follow-up. In conclusion, OCT-A provides a useful approach for monitoring the CNV Type 2 over the time.