Why is laser treatment required for diabetic retinopathy?

Diabetic retinopathy eventually progresses to a stage in which blood flow to the retina of both eyes comes down. Once this happens, compensatory new blood vessels grow on the retina which are unhealthy and fragile. These break and bleed easily causing vitreous haemorrhage and retinal detachment. This eventually leads to blindness.

Laser treatment done for proliferative diabetic retinopathy is called laser photocoagulation. This laser produces a tiny burn in the area treated. Hence when areas without proper blood flow are treated with laser burns, blood flow diverts to the unlasered healthy retina, preserving its health. As a result, new blood vessel growth stops and the retinopathy becomes stable.