While OCT has revolutionized wet AMD diagnosis and treatment, a new study now suggests the next generation of imaging—OCT angiography (OCT-A)—may be able to detect changes in choroidal neovascularization (CNV) and response to anti-VEGF therapy. 

Researchers from Austria enrolled 32 treatment naïve patients with CNV lesions that were seen on 6x6mm OCT-A images. Patients were followed for the first three months with mandatory visits at days seven and 14 after each anti-VEGF treatment. The study included a subgroup of 14 eyes that were also seen on days one and three after the initial injection. Aflibercept was administered at baseline and again at days 30 and 60. The investigators analyzed CNV and vessel areas, vessel density, number of junctions, junction density, total and average vessel lengths, total number of endpoints and lacunarity.

During follow-up, the researchers observed a characteristic neovascular response curve with a dynamic decrease in lesion size within days, and a reactive increase two weeks after initial treatment. The investigators also saw an undulating pattern for all neovascular parameters except for vascular density, with variable statistical significance.

Due to a flattening of the therapeutic response as early as the second treatment, CNV lesion size and most of the related parameters had an increase in activity above baseline at the end of the loading phase, the study noted.

Additionally, lesion size was the leading feature of reactivation by an approximate increase of 19.3% after three monthly injections.

Based on lesion size, the subgroup analysis revealed a significant correlation between best-corrected visual acuity and quantitative change in lesion size over time, but not baseline size.

“More than a decade after the approval of anti-VEGF for widespread clinical use, an advanced understanding of the therapeutic mechanisms may become available with SS-OCT-A as a valuable diagnostic companion offering the necessary insight into the vascular biology of neovascular AMD,” the researchers wrote in their paper.