What is the risk of blindness once a CNV develops?
The risk of visual loss depends on the size, location, and angiographic features of the CNV. In general, the closer the CNV is to the fovea, the larger the CNV, and the more well defined the CNV, the worse the prognosis. If a patient has a well defined subfoveal CNV (i.e., the borders of the CNV are well demarcated angiographically), the risk of severe visual loss (i.e., e” 6 line loss of vision on the visual acuity chart) is 45%, and the mean visual acuity is 20/500 at four years follow-up without treatment, vs. 23% and 20/320 among treated eyes, respectively. (Patients with visual acuity equal to or worse than 20/200 are legally blind.) Patients with poorly defined CNVs have a somewhat better prognosis.
