Occult CNV

Occult CNV has been categorized as fibrovascular PED or late leakage of undetermined source⁽¹³⁾.

Fibrovascular PED (type I occult CNV) is defined as an irregular elevation of the RPE associated with stippled hyperfluorescence apparent 1 to 2 minutes after fluorescein injection and ill-defined staining or leakage in the late frames (Fig. 19-20).

It differs from classic CNV in that the early hyperfluorescence is not as bright and the boundaries usually are indeterminate.

Late leakage of undetermined source (type II occult CNV) lacks a discernible, well-demarcated area of leakage in the early angiographic frames.

Speckled hyperfluorescence with no visible source becomes apparent 2 to 5 minutes after dye injection (Fig. 21).