What is Laser Photocoagulation?
Laser photocoagulation is a treatment for several retinal diseases, most commonly, proliferative diabetic retinopathy. A laser is used to create burns in the retina to prevent neovascularization. Photocoagulation involves protein denaturation and is the result of tissue absorption of radiant energy with conversion to heat. It is not the same type of process used in refractive surgeries like LASIK. Due to the selection of a single wavelength, the laser can reduce the amount of damage to adjacent tissues.
Key Takeaways
- Laser photocoagulation creates retinal burns to prevent neovascularization.
- Research shows panretinal photocoagulation is effective in treating proliferative diabetic retinopathy and diabetic macular edema.
- Today, laser photocoagulation allows for more specific targeting and fewer side effects.
Understanding Laser Photocoagulation
Retinal laser photocoagulation has changed immensely since its discovery in the 1940s. The invention of the laser propelled the widespread use of photocoagulation for the treatment of retinal diseases. The laser allows for the choice of electromagnetic wavelength and delivery options, such as continuous and micropulse modes. These options provide the eye doctor with accurate targeting of retinal tissue and prevent detrimental side effects like central blind spots.
The Diabetic Retinopathy Study found that panretinal photocoagulation (PRP) reduced the risk of severe vision loss in patients with proliferative diabetic retinopathy (PDR) or severe nonproliferative diabetic retinopathy (NPDR) by at least 50% when compared with untreated eyes. Additionally, the Early Treatment Diabetic Retinopathy Study Research Group found that the risk of vision loss in patients with clinically significant diabetic macular edema (DME) was substantially reduced by focal photocoagulation.
Risk Factors for Laser Photocoagulation
Proliferative diabetic retinopathy (PDR) is a sight-threatening disease. In PDR, new, leaky blood vessels form that are fragile and are associated with fibrosis and traction in the retina increasing a patient’s risk of retinal detachment.
Diabetic macular edema (DME) can occur at any stage of diabetic retinopathy and is the leading cause of severe visual loss in diabetic patients. Retinal thickening occurs because of fluid accumulation originating from leaky microaneurysms and diffuse blood vessel leakage. The microaneurysms can be treated with a focal laser, while diffuse vessel leakage is treated by the application of a macular grid laser, which spares the foveal avascular zone. The patient can maintain central vision.
Several other clinical trials demonstrate that laser photocoagulation is effective for treating the following retinal diseases: subfoveal choroidal neovascularization in patients with macular degeneration, retinopathy of prematurity, and macular edema secondary to a branch retinal vein occlusion.
Laser Photocoagulation Symptoms
After treatment, the patients will have scarring at the locations the retina was treated. Depending on the number of quadrants of treatment, an individual will have some degree of peripheral vision loss.
Laser Photocoagulation Treatment
Panretinal photocoagulation (PRP) involves 2000 laser burns applied to the peripheral retina which leads to neovascularization regression. Although the mechanism of action is yet to be fully elucidated, PRP is currently one of the standard treatments for PDR. Some ophthalmologists prefer to divide treatment into two or more sessions while others elect to perform treatment in a single session.
Macular grid laser is the treatment for macular edema in both diabetic retinopathy and branch retinal vein occlusions. A focal laser is used to treat microaneurysms.
