The retina is the innermost layer of the eye that produces vision. It is made up of cells called rods and cones that convert light into nerve impulses, which then travel through the optic nerve to the brain. The blood vessels in your retina help nourish these cells with oxygen and nutrients.
When a vein in this network of blood vessels becomes blocked or narrowed, it can cause bleeding into the retina and damage to the cells within it. This condition is called branch retinal vein occlusion (BRVO). The most common symptom of BRVO is sudden loss of vision in one eye, usually without pain or other symptoms. If you experience any sudden vision loss, contact your doctor immediately to schedule an appointment for examination.
Read on to learn more about Treatment Options for Branch Retinal Vein Occlusion and Treatment Options for Branch Retinal Vein Occlusion
Laser For Branch Retinal Vein Occlusion
Branch retinal vein occlusion (BRVO) is the second most common retinal vascular disease after diabetic retinopathy, affecting approximately 180,000 people in the United States each year. Risk factors for retinal vein occlusions (RVOs) include glaucoma, older age, and systemic conditions such as diabetes, hypertension, systemic vascular disease, and smoking status.1,2
Although many treatments for BRVO have been tried, none was found to be effective before the Branch Vein Occlusion study was begun in 1977. That study, after a mean follow-up 3.1 years in 139 eyes randomized to argon laser photocoagulation or control, found a statistically significant improvement in visual acuity from baseline in treated eyes (P=.0005).3
The BVOS investigators in 1984 recommended argon laser photocoagulation for treatment of macular edema due to BRVO, and to this day laser photocoagulation remains the standard care for the condition.
In recent years, there has been increasing interest in addressing macular edema due to BRVO pharmacologically. Several case reports and small series suggested that intravitreal injection of triamcinolone acetonide could be effective in reducing edema in patients with BRVO. However, a large-scale, controlled clinical trial4 failed to show an advantage of triamcinolone injection over standard laser treatment.
The SCORE-BRVO study4 compared the safety and efficacy of intravitreal injection of 1 mg or 4 mg triamcinolone to standard care with grid photocoagulation in eyes with macular edema secondary to BRVO. In 411 patients randomized to one of three treatment groups, there were no significant differences between the groups in the primary outcome measure of gain in visual acuity of 15 or more letters at 1 year. However, the rates of adverse events, particularly elevated intraocular pressure (IOP) and cataract development, were higher in the 4-mg triamcinolone treatment group than in the other two groups.
The SCORE-BRVO investigators concluded that grid photocoagulation remains the standard of care for patients with visual acuity loss associated with macular edema secondary to BRVO, and that laser photocoagulation should still be the benchmark against which other treatments for BRVO are evaluated.
Recently it was recognized that vascular endothelial growth factor (VEGF) is an important stimulus of macular edema in RVOs,5 and as a results there has been increased interest in the use of VEGF inhibitors for the treatment of BRVO. The BRAVO trial6 showed promising safety and efficacy results at its 6-month primary endpoint, with visual improvements seen in patients treated monthly with intravitreal injection of ranibizumab (Lucentis, Genentech). However, although rescue laser was allowed in the trial, the design did not include a laser-alone arm for comparison. This, along with the need for longer-term results with VEGF inhibition, still leaves us with laser photocoagulation as the standard of care for BRVO.
SUBTHRESHOLD (SUBVISIBLE) DIODE MICROPULSE LASER
The studies cited above each employed conventional suprathreshold thermal laser photocoagulation, the principles of which have remained remarkably unchanged since the days of the Diabetic Retinopathy Study7 and the Early Treatment Diabetic Retinopathy Study.8 In these landmark studies it was noted that, in general, treatment efficacy increased with treatment density, while treatment complications increased with treatment intensity. In subsequent years, practitioners have modified these classic photocoagulation techniques hoping to improve the safety of treatment, primarily by reducing treatment intensity. The micropulsed diode laser, developed in the 1990s, is one tool that has been employed to this end.
However, when micropulse diode lasers became available, most practitioners continued using these instruments with the same mindset: The aim of the therapy was still to make burns—albeit less intense—in the retina, as it was assumed that thermal retinal destruction was necessary to achieve the desired therapeutic effect. The persistence of thermal chorioretinal damage dictated continued use of traditional grid and modified-grid treatment techniques to minimize the risk of treatment-associated visual loss.
In 2000, when I started using this technology (IQ 810 laser, Iridex Corporation, Mountain View, CA), I took a different approach. My intent was avoid any burns, to perform an effective treatment that caused no thermal retinal damage. To this end I developed a new treatment technique aimed at maximizing the potential benefits of the micropulsed diode laser for retinal vascular disease, termed low-intensity/high-density treatment. With reports beginning in 2005, my colleagues and I were able to show that this new approach to subthreshold (subvisible) diode micropulse laser photocoagulation (SDM) was effective in the treatment of clinically significant diabetic macular edema (DME) and proliferative diabetic retinopathy without any detectable laser-induced retinal damage.9-13 Subsequent randomized clinical trials have confirmed our findings in the treatment of diabetic macular edema.14-16
SDM offers a number of advantages over conventional thermal laser. Because of its unique safety profile, SDM can be used to treat patients earlier because there is no risk, possibly improving treatment outcomes. Due to the absence of retinal damage, retreatment can be performed as necessary without limit.
Additionally, SDM can be combined with pharmacologic therapy, such as steroid or anti-VEGF agents, for retina-sparing disease management. The optimal timing and sequencing of drug and laser treatments to achieve complementary and/or synergistic action and avoid inadvertent inhibition of either treatment is likely important, but unknown. In the absence of thermal retinal injury, SDM appears to work by altering retinal pigment epithelial (RPE) cytokine production. Thus, I generally wait at least 1 month between SDM and drug administration to minimize the risk of the drug “cancelling out” the effect of laser treatment.
Unlike conventional argon laser, the diode laser, operating at 810 nm in the infrared, easily penetrates the retina and retinal blood while targeting the RPE. This difference in wavelength and retinal penetration provides a number of clinical advantages over conventional laser. SDM treatment can be performed without waiting for retinal hemorrhage to clear, a common challenge in BRVO. It also means that treatment intensity does not have to be increased to penetrate a markedly thickened macula. For macular SDM treatment, I use exactly the same parameters on every patient regardless of retinal thickness or fundus coloration.
Laser For Branch Retinal Vein Occlusion: An Overview
Branch retinal vein occlusion (BRVO) is a common retinal vascular disorder that affects the small veins in the retina. This condition can lead to vision loss and may require treatment to prevent further damage. One of the treatment options for BRVO is laser therapy. In this article, we’ll explore the use of laser for branch retinal vein occlusion.
Understanding Branch Retinal Vein Occlusion
Before we delve into the use of laser for BRVO, let’s first understand what this condition is. BRVO occurs when a vein in the retina becomes blocked or occluded, causing a backup of blood flow and fluid in the affected area. This can lead to swelling, bleeding, and damage to the surrounding tissue. BRVO can occur in any part of the retina, but it most commonly affects the branches of the retinal vein.
Symptoms of BRVO may include blurred vision, distorted vision, and the appearance of dark spots or floaters in the affected eye. If left untreated, BRVO can lead to permanent vision loss.
Treatment Options for Branch Retinal Vein Occlusion
The goal of treatment for BRVO is to improve blood flow in the affected area, reduce swelling, and prevent further damage to the retina. There are several treatment options available for BRVO, including:
- Intravitreal injections: These injections deliver medication directly into the eye to reduce swelling and inflammation.
- Anti-VEGF therapy: This therapy targets a protein called vascular endothelial growth factor (VEGF) that contributes to the development of abnormal blood vessels in the retina.
- Laser therapy: Laser therapy can be used to seal leaking blood vessels and reduce swelling in the retina.
Laser Therapy for Branch Retinal Vein Occlusion
Laser therapy is a common treatment option for BRVO. During this procedure, a special laser is used to create small burns on the retina. These burns cause scar tissue to form, which seals off leaking blood vessels and reduces swelling in the affected area.
Laser therapy is typically performed in an outpatient setting and can be completed in a single session. The procedure is usually painless, although some patients may experience mild discomfort or a sensation of heat during the treatment.
Benefits and Risks of Laser Therapy for BRVO
Laser therapy for BRVO has several benefits, including:
- Improved vision: Laser therapy can help reduce swelling in the retina, which can improve vision in the affected eye.
- Quick and painless: Laser therapy is a quick and painless procedure that can be completed in a single session.
- Low risk of complications: Laser therapy is a low-risk procedure that has few complications.