How can abnormal new blood vessels in proliferative diabetic retinopathy lead to bleeding and retinal detachment?

In proliferative diabetic retinopathy, the body attempts to compensate for retinal ischemia by growing new blood vessels on the retina and optic disk. These new vessels are structurally unstable and fragile, making them highly susceptible to breaking and causing hemorrhage into the vitreous cavity.123

Beyond bleeding, these abnormal vessels can lead to retinal detachment through the formation of scar tissue. As these vessels grow, they are often accompanied by the development of abnormal membranes on the surface of the retina. These membranes can contract, exerting mechanical traction on the retina. This process, known as a tractional detachment, occurs when the contracting tissue pulls the light-sensing retina away from the underlying retinal pigment epithelium.24

If left untreated, these complications—recurrent vitreous hemorrhage and tractional retinal detachment—can result in significant and permanent vision loss. Management often involves laser photocoagulation to slow vessel growth or surgical interventions such as a vitrectomy to address bleeding and reattach the retina.142