Pan retinal photocoagulation (PRP) is a laser eye treatment designed to address specific retinal conditions. Its main purpose is to prevent severe vision loss by targeting abnormal blood vessel growth in the eye.
Understanding Pan Retinal Photocoagulation
Pan retinal photocoagulation works by applying a laser to the peripheral retina, creating small, precise burns. The goal of these burns is to reduce the retina’s demand for oxygen in the treated areas. By doing so, PRP helps to inhibit the growth of abnormal and fragile blood vessels, a process known as neovascularization, which can lead to bleeding and retinal detachment. The laser energy is absorbed by pigmented cells in the retinal pigment epithelium, causing thermal coagulation of the targeted tissue. This process leads to the closure of abnormal blood vessels and a decrease in vascular endothelial growth factor (VEGF), a protein that stimulates new vessel formation. The treatment specifically targets the outer regions of the retina, leaving the central vision unaffected.
Eye Conditions Treated with PRP
Proliferative diabetic retinopathy (PDR) is a significant condition treated with PRP. In PDR, high blood sugar levels damage the existing retinal blood vessels, leading to areas of poor blood flow and a lack of oxygen. This oxygen deprivation triggers the retina to produce new, fragile blood vessels that can rupture and bleed, causing vitreous hemorrhage or even retinal detachment. PRP aims to stop this abnormal vessel growth by treating the oxygen-starved peripheral areas of the retina.
The procedure is also used in cases of severe retinal vein occlusions, where a blocked vein in the retina can also lead to oxygen deprivation and the subsequent growth of new, abnormal blood vessels. These new vessels are prone to bleeding and can cause complications like neovascular glaucoma, a painful condition involving high eye pressure. In such instances, PRP helps reduce the risk of these severe complications, preserving existing vision.
What to Expect During the Procedure
Before the PRP procedure, your eye will typically be dilated with eye drops to widen the pupil and numbed with anesthetic drops. In some cases, a local anesthetic injection may be given around or behind the eye to minimize discomfort. You will then be positioned with your chin on a chin-rest and your forehead against a forehead-rest. A special contact lens is placed on the front of your eye to help focus the laser precisely on the retina.
During the laser application, you may experience flashes of light and a mild pinching or aching sensation with each laser spot. The procedure typically lasts between 15 to 30 minutes per session, depending on the extent of treatment needed. Many patients require multiple sessions, often two or more, to complete the full treatment, with the initial treatment consisting of approximately 1,500 to 2,000 laser spots per eye.
After the Procedure: Recovery and Outcomes
Immediately after the PRP procedure, it is common to experience temporary blurred vision and increased light sensitivity. Mild ache or discomfort in the treated eye can usually be managed with over-the-counter pain medication for one to two days. The blurred vision typically resolves within a few days to a week, though for some, it might persist longer. It is advised to arrange for someone to drive you home after the procedure, as your vision may be impaired for several hours due to the dilating drops.
Long-term visual outcomes of PRP focus primarily on preserving existing vision and preventing further loss, rather than restoring vision that has already been compromised. Patients may experience a reduction in peripheral (side) vision, as well as some changes in night vision or color perception. While serious complications are rare, it is important to attend all follow-up appointments to monitor the eye’s response to treatment and address any unusual symptoms like increased flashes, floaters, or significant pain. Further treatment, such as additional laser sessions or anti-VEGF injections, may be necessary if the condition progresses or if fluid buildup occurs in the macula.