Aims To investigate aqueous humour changes in vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) levels in patients with choroidal neovascularisation (CNV) secondary to pathological myopia (mCNV) before and after intravitreal ranibizumab injection (IVR).

Methods This was a prospective, case–control study investigating aqueous levels of VEGF and PEDF in eyes with mCNV treated with IVR.

Results Mean VEGF and PEDF levels in the aqueous humour of control patients were 25.7±4.9 pg/mL and 12.6±3.5 ng/mL, respectively. Lower levels of both VEGF (19.5±5.4 pg/mL) and PEDF (4.7±2.2 ng/mL) were found in patients with mCNV before IVR. After IVR, aqueous VEGF levels significantly reduced to 6.5±2.7 pg/mL, while PEDF levels significantly increased to 35.8±11.4 ng/mL. VEGF and PEDF levels significantly correlated with each other, and with best-corrected visual acuity and central retinal thickness.

Conclusions The VEGF and PEDF levels in aqueous humour were significantly lower in the myopic group than in controls. Moreover, IVR resulted in reduced VEGF and increased PEDF levels in patients with mCNV. In mCNV, neovascularisation is associated with inappropriate VEGF and PEDF expression. A balance between VEGF and PEDF is crucial to prevent CNV development.

Trial registration number NCT02175940.