Peripapillary crescent enlargement in highly myopic eyes evaluated by fluorescein and indocyanine green angiography

Aims: To evaluate angiographic features of myopic crescents using fluorescein angiography ( FA) and indocyanine green angiography (IA). Methods: FA and IA angiograms of 88 highly myopic eyes (47 consecutive patients) were reviewed. The follow up period ranged from 5-28 years. Results: FA revealed two zones of the myopic crescent: a consistently hypofluorescent inner zone and an outer zone with delayed choroidal filling. IA revealed dislocation of the Zinn-Haller ring to the border between the two zones. Myopic crescent enlargement occurred in 68.1%. Only the outer zone increased significantly in most of the eyes with enlarged crescents. Conclusions: The inner zone might develop as a result of mechanical stretching, and the outer zone might be the result a secondary circulatory disturbance and mechanical stretching.