Laser is a highly concentrated beam of purified light that carry a large amount of energy. It can be used to treat tissues inside your eye without having to make a wound. Yellow-green lasers are used to burn sick retinal tissue in e.g., diabetic retinopathy, or to seal tears in the retina. It can also be used to destroy abnormal blood vessels and to reduce retinal swelling. Very powerful lasers can be used to create a new conduit in the retinal blood vessels to divert the blood flow around an obstruction in patients with retinal vein occlusion. Another laser, called YAG laser, is used to precisely cut tissues inside the eye.