Attention on type 3 NV
The origin of the lesion has received much attention since it was first recognized when Hartnett et al. suggested that the lesion be called retinal vascular abnormalities associated with pigment epithelial detachment.
Lawrence Yannuzzi, MD, and associates first proposed that type 3 NV be described by the term retinal angiomatous proliferation (RAP) in 2001, and they subclassified it into three stages as a result of imaging findings that seemed to show its origins in the retinal circulation and later was associated with the development of chorioretinal anastomosis.
Gass et al. went a step further and hypothesized that type 3 NV originated from preclinical type 1 NV forming an occult chorioretinal anastomosis.
The findings from spectral-domain optical coherence tomography (SD-OCT), real-time angiography, and OCT angiography appear to show that type 3 NV originates from the deep retinal circulation, with the latest classification based on OCT findings presuming the origin of type 3 NV to be from the deep vascular complex followed by a disruption of outer retinal layers and penetration through the RPE.