By Khalid F. Tabbara, MD
This large, retrospective study found that choroidal neovascularization (CNV) is rare in patients with anterior and intermediate uveitis and is commonly associated with conditions characterized by inflammation involving the retina-choroid interface. These include punctate inner choroiditis, multifocal choroiditis, Vogt-Koyanagi-Harada (VKH) disease and preretinal neovascularization.
Early detection of CNV in patients with posterior uveitis may prevent visual loss. The risk of CNV is highest in the early period and close observation is therefore recommended in higher risk patients.
The authors reviewed the charts of 8,868 uveitis patients seen at five tertiary care academic ocular inflammation centers from 1978 to 2007. Patients with HIV were excluded.
The incidence of CNV was found to be 2 percent, with an increase over a period of five years in cases with posterior uveitis. They found that CNV is extremely rare in patients with anterior uveitis and intermediate uveitis but is seen commonly in patients affecting the posterior segment and specifically at the retina-choroid interface.
In addition, they found that preretinal neovascularization, which is commonly associated with retinal ischemia and is mediated by VEGFs, is associated with a more than three-fold risk of CNV.
Chorioretinal inflammation appears to play a critical role in the development of CNV. Inflammatory cells secrete proteolytic enzymes and lead to damage and degradation of Bruch’s membrane with upregulation of cytokines that promote the growth of CNV in the subretinal pigment epithelial space. CNV may potentially lead to exudation, edema, hemorrhages and fibrosis with decrease in visual acuity.
They conclude that patients with conditions that affect the anatomic areas close to Bruch’s membrane may be at higher risk of CNV and should be observed closely by optical coherence tomography and fundus fluorescein angiography. Patients with retinal vasculitis and evidence of retinal ischemia should be closely observed for the development of CNV as well.