Myopic choroidal neovascularisation (CNV) is a complication of myopia that causes visual impairment. The choroid is the vascular layer of the eye between the retina and the sclera. In the myopic eye it is thought that the elongation of the anteroposterior axis causes stress, which induces the creation of new blood vessels in the choroid. It is this neovascularistion that causes the decrease in visual acuity.