Purpose: To identify anomalies of choroidal venous structure in highly myopic (HM) eyes.
Methods: Widefield indocyanine green angiographic images of 175 HM eyes (refractive error ≤ -6.0D diopters or axial length >26.5 mm) and 100 control eyes taken between January 2014 and December 2018 were reviewed.
Results: There were no significant differences in age and gender between HM patients and controls. Three types of changes of large choroidal veins were found in 103 HM eyes (58.86%): Asymmetry of vortex veins in 44 eyes (25.14%), isolated long vein across the macula in 58 eyes (33.14%), and intervortex anastomoses in 25 eyes (14.29%). Similar changes in controls were found in 12 eyes (12%), 0 eye (0%), and 2 eyes (2%), respectively, which were significantly lower than those in the HM group (all P < 0.05). The patterns of asymmetry were affected by steeper staphyloma edges and anastomoses were observed through large trunks and terminal venules. In two eyes with large trunk anastomosis, attenuation of the less dominant vortex vein was observed afterward.
Conclusion: Choroidal venous anomalies are more common in HM eyes than controls. Choroidal venous structure in HM eyes may be altering continuously, and such changes may underlie the development of myopic maculopathy.