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Neovascular AMD typically presents with hemorrhage and swelling of the macula. In chronic lesions, hard exudate and fibrosis may also develop. These lesion components can be documented with CFP, fluorescein angiography (FA), and indocyanine green angiography (ICGA). FA is widely considered as the gold standard for diagnosis of neovascular AMD. Two patterns of leakage are generally described: classic and occult.

Classic pattern (Fig. 9) appears as a well-defined hyperfluorescent lesion in the early phase of the angiogram, often with a “lacy” pattern, which leaks (increases in intensity and size) in the late phase. This appearance is explained by the presence of the CNV above the RPE (type 2 CNV).

Occult pattern (Fig. 10) appears either as fibrovascular PED, which appears as an area of elevated, stippled hyperfluorescence when viewed stereoscopically, or as late leakage of unknown origin. This appearance results from CNV growing beneath the RPE (type 1 CNV). Type 1 CNVs are often associated with a serous PED which appears as a well-circumscribed dome-shaped elevation of the RPE in which dye can be seen to pool.

Fig. 9. Type 2 choroidal neovascularization on fluorescein angiography. In the early arteriovenous phase (a), a hyperfluorescent network with lacy pattern can be seen clearly. In the late phase (b), profuse leakage can be seen, as evident from the increase in intensity and size of the area of hyperfluorescence, extending beyond the margin of the network seen in the early phase.

Fig. 10. Type 1 choroidal neovascularization. On color photograph (a), a dome-shaped elevation at the level of RPE can be seen. This area correspond to a pigment epithelial detachment which appears dark on ICGA (b) and FA (c, d). At the superior corner, a notch in the PED can be seen as stippled hyperfluorescence on FA with mild leakage, which suggests an area of fibrovascular PED. The corresponding area appears as a plaque on ICGA.

Type 3 CNV, also known as RAP originates from intraretinal neovascularization which progresses and extends beneath the neurosensory retina forming subretinal neovascularization and vascularized PED (Fig. 11). On FA, a focal area of early leakage with right-angled “diving vessel” may be seen. PEDs are commonly associated with stage 2 and 3 RAP. Dynamic angiography is valuable in determining the origin and direction of filling of the lesion [9].

CNV lesions can also be composed of a combination of the above lesions. “Predominantly classic” lesions are composed of >50% of classic CNV, whereas “Minimally classic” lesions are composed of <50% classic CNV. Other lesion components, such as thick blood or blocked fibrosis may appear as areas of hypofluorescence and staining respectively, and may obscure the view of the underlying area which may harbor CNV. Tense PEDs may be complicated by RPE tear (Fig. 12). This may appear as submacular hemorrhage, often associated with a sudden drop in vision. RPE tears have a characteristic appearance on FA, which is helpful to make the diagnosis. The area devoid of RPE appears as a sharply demarcated area of hyperfluorescence which does not leak, due to unmasking of underlying choroidal vasculature. The stump of RPE typically appears dark, with variable leakage depending on whether the underlying CNV is still active. On ICGA, CNV lesions typically appear as a hot spot or plaque in the late phase (Fig. 10).

Fig. 11. Type 3 neovascularization (retinal angiomatous proliferation, RAP). On color photograph (a), a superficial hemorrhage can be seen on a background of reticular drusen. On the fluorescein angiogram (FA), the RAP lesion can be seen as an aneurysmal lesion (arrow) in the arteriovenous phase (b) which originates from anastomosis between two retinal vessels, with a characteristic “diving vessel” configuration. In the late-phase FA (c), a pigment epithelial detachment appears as a dome-shaped elevated area surrounding the RAP lesion. The RAP lesion appears as a hot spot on indocyanine angiography (d).

Fig. 12. Retinal pigment epithelial (RPE) tear. An RPE tear has developed in the eye with type 1 choroidal neovascularization in Figure 10. A round well-defined area of bearing of underlying choroidal vessels can be seen on color photograph (a) and appears as a window defect on the fluorescein angiogram (b) and indocyanine green angiogram (c). The stump of the torn RPE appears as a dark patch (*) at the superior border of the previously noted pigment epithelial detachment.

Fig. 13. Polypoidal choroidal vasculopathy. Orange subretinal nodules can be seen on color fundus photography (a) (white arrows). On fluorescein angiogram, the appearance of occult leakage pattern is indistinguishable from type 1 choroidal neovascularization (b). On indocyanine green angiography (c), however, a clear string of polyps (white arrows) can be identified, as well as a branching vascular network (black arrows).