Pan Retinal Photocoagulation (PRP) is a laser treatment directed towards unhealthy retina. Due to diminished blood supply by vascular diseases such as diabetes and vein occlusions, areas of the peripheral retina become deficient in oxygen (hypoxia or ischemia). The hypoxic retina then develops abnormal blood vessels which are fragile and often bleed, leading to vitreous hemorrhage. In addition, tractional retinal detachment, macular edema, and neovascular glaucoma may also occur secondary to ischemic retinopathy.
PRP is laser light applied to the peripheral retina. This destroys small spots of retina, decreasing its need for oxygen and reversing the ischemia. This reduces the inducement to grow new blood vessels and decreases the likelihood of hemorrhage or other vision threatening events. With less ischemic retina, the chance of abnormal new vessel growth is reduced. Without abnormal new vessels, rates of vitreous hemorrhage or vision loss are reduced.
The laser light is focused on the retina by the doctor. A hand held lens or contacts lens is used. Topical drops or injection of anesthesia is used to minimize discomfort. The procedure usually takes several minutes. The vision is often blurred for several hours, but then returns. Redness and tearing may also occur.
The purpose of PRP is to reverse ischemic retinal disease and prevent loss of vision, and even loss of the eye. PRP avoids the central retina and therefore doesn’t usually affect central acuity. Because PRP does treat the side, or peripheral retina, decreased peripheral and night vision may be noticed.