Type 2 macular neovascularization is thought to be a rare condition in AMD. A 2017 paper that presented a new classification system for AMD defines type 2 macular neovascularization as a vascular network present only in the subretinal space, in contrast to type 1, which originates from the choroid and remains beneath the retinal pigment epithelium (e.g., polypoidal choroidal vasculopathy—an aneurysmal type 1 subtype) and type 3 (also called retinal angiomatous proliferation), and which reflects a distinct form of neovascular AMD with an intraretinal origin and different pathophysiology.1-2
While types 1 and 3 are more common in neovascular AMD and more widely studied, type 2 macular neovascularization is thought to be present in only 0.8% to 9% of cases. Its accompanying factors are still unclear, so a recent study investigated its characteristics.3
The retrospective observational case series included treatment-naïve patients with neovascular AMD who were classified by anatomic subtype of neovascular lesions. The researchers used a variety of imaging techniques, including near-infrared fundus reflectance, blue-peak fundus autofluorescence, spectral-domain OCT, high-resolution fluorescein angiography and indocyanine green angiography.3
Of the 835 eyes (749 patients), the researchers diagnosed type 2 macular neovascularization in 3.2% of eyes (27 eyes). Table 1 shows the distribution of drusen characteristics in eyes with type 2 macular neovascularization and the 23 non-neovascular fellow eyes.3
The researchers concluded that type 2 macular neovascularization was indeed a rare entity in AMD. Interestingly, though the presence of drusen typically indicates early and intermediate AMD, the researchers found that type 2 macular neovascularization was frequently seen in the absence of drusen.3 They wrote that their findings “contribute to the heterogeneity of phenotypes related to pure type-2 lesions.”3
Table 1. Drusen Characteristics in Eyes with Type-2 Macular Neovascularization3
|Neovascular eyes||Non-neovascular fellow eyes|
|No drusen||10 (37%)||9 (39.1%)|
|Drusen <63μm||2 (7.4%)||2 (8.7%)|
|Drusen ≥63μm||10 (37%)||9 (39.1%)|
|Cuticular drusen||2 (7.4%)||1 (4.3%)|
|Subretinal drusenoid deposits (SDD)||8 (29.6%)||5 (21.7%)|
|Dot SDD||3 (11.1%)||2 (8.7%)|
|Ribbon SDD||1 (4%)||1 (4.3%)|
|Dot and ribbon SDD||4 (15%)||2 (8.7%)|
|Extrafoveal atrophy||0 (0%)||1 (4.3%)|
|Subfoveal atrophy||0 (0%)||0 (0%)|
|Fibrosis||0 (0%)||3 (13%)|
1. Spaide RF. Improving the age-related macular degeneration construct. A new classification system. Retina. 2018;38(5):891-99.
2. Spaide RF, Jaffe GJ, Sarraf D, et al. Consensus nomenclature for reporting neovascular age-related macular degeneration data: Consensus on neovascular age-related macular degeneration nomenclature study group. Ophthalmology. 2020;127:616-36.
3. Ahmed D, Stattin M, Haas A-M, et al. Drusen characteristics of type 2 macular neovascularization in age-related macular degeneration. BMC Ophthalmology. September 25, 2020. [Epub ahead of print].