Three weeks after an intravitreal anti-VEGF injection given for proliferative diabetic retinopathy, a patient returns with reduced vision. OCT now shows a tractional membrane pulling the fovea upward, with a localized tractional detachment that was not present before the injection. What is the underlying mechanism?

• A Direct toxic effect of VEGF blockade on photoreceptors
• B Rebound VEGF surge causing exudative retinal detachment
• C Contraction and fibrotic organization of regressed neovascular complexes, increasing traction ✓
• D Sterile inflammatory reaction to the injection vehicle

Explanation

Anti-VEGF agents rapidly regress active neovascular tissue, but the regressed vessels are replaced by denser fibrovascular scar that contracts. This can convert a stable fibrovascular proliferation into a tractional retinal detachment, sometimes within days to weeks. This recognized risk is why some surgeons inject close to planned vitrectomy and why patients must be reviewed early. Rebound VEGF surge occurs months later and causes edema, not acute traction.

Reference: Ryan's Retina, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.