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Pathologic Myopia and Myopic CNV
ОглавлениеFA is considered the gold standard to confirm the diagnosis of CNV secondary to pathologic myopia (mCNV) [17–19]. mCNV typically appear as type 2 CNVs, with a classic leakage pattern (Fig. 31). Compared to neovascular AMD, there is usually less subretinal fluid or exudative changes associated with mCNV. Similarly, FA has been shown to be more sensitive than OCT in detecting activity in mCNV. mCNV can often be detected in close proximity to lacquer cracks. These are linear breaks in Bruch's membrane. Detection of lacquer cracks with conventional examination can be difficult. ICGA is widely accepted as the best method for detecting lacquer cracks, which typically appear as linear hypofluorescence in the late phase. When lacquer cracks develop or extend, subretinal hemorrhage may develop. These can be difficult to distinguish from mCNV on fundus examination, but can be readily differentiated based on FA and ICGA. In less severe stages of myopic maculopathy, diffuse atrophy is characterized by mild hyperfluorescence in late-phase FA and decrease in choroidal vasculature on ICGA. Areas of patchy chorioretinal atrophy are characterized by well-defined areas of hypofluorescence on FA and ICGA due to choroidal filling defect.