Purpose: To determine whether the choroidal vasculature is altered in highly myopic eyes with or without posterior staphyloma using indocyanine green angiography. In addition, to analyze long-term changes of the choroidal vasculature in patients who were observed for at least 5 years with indocyanine green angiography.
Design: Consecutive, retrospective, observational case series.
Participants: Three hundred twenty-one eyes of 195 patients with high myopia.
Methods: Indocyanine green angiograms were analyzed, and the effect of posterior staphyloma on the choroidal vasculature was studied. Changes in the indocyanine green-determined choroidal vasculature detected after at least 5 years were analyzed in 57 eyes of 36 patients.
Main outcome measures: Indocyanine green angiography assessment of the choroidal vasculature.
Results: A choroidal flush was detected in all of the control eyes but only 52 (16.2%) of the 321 highly myopic eyes. A displacement of the entry site of the posterior ciliary arteries into the choroid was observed in 76.6% of the eyes with posterior staphyloma and in 25.3% of the eyes without (P<0.001). There were fewer large choroidal veins in the posterior fundus, and in some cases, there was marked variation in the diameter of neighboring large choroidal veins in the highly myopic patients. Of 57 eyes that were followed for >5 years, 9 (15.8%) showed changes in the choroidal vascular structure in the later indocyanine green angiograms. Four of 9 eyes showed dilation or enlargement of posterior routes of choroidal venous outflow, 5 showed narrowing of the large choroidal veins, and 2 had a loss of the large choroidal veins (overlapped). One patient developed choroidal neovascularization after loss of the large choroidal veins.
Conclusions: These findings indicate that the choroidal vasculature can be significantly altered in highly myopic eyes, and this is more prevalent in eyes with posterior staphyloma. Whether these alterations are related to the development of chorioretinal lesions in highly myopic eyes is now being investigated.