Pigment epithelial detachment (PED) is an eye condition characterized by the separation of the retinal pigment epithelium (RPE) layer from the underlying Bruch’s membrane. This separation creates a space that can fill with fluid, blood, or other materials, disrupting the normal function of the retina.
Understanding Pigment Epithelial Detachment
Pigment epithelial detachment (PED) presents in various forms, each with distinct underlying characteristics. These classifications are important as they often guide the chosen management approach.
Serous PED involves the accumulation of clear fluid, leading to a dome-shaped elevation of the RPE. This type typically shows a smooth, dome-shaped elevation on optical coherence tomography (OCT) scans. Hemorrhagic PED, in contrast, is characterized by the presence of blood beneath the RPE, often appearing as a darker elevation. Drusenoid PED results from the buildup of drusen, which are waste products, between the RPE and Bruch’s membrane. Drusenoid PEDs usually appear as yellow-white elevations with scalloped borders and a somewhat irregular surface. These different types reflect varied disease processes and can influence the prognosis and treatment selection.
Observation as a Management Strategy
For certain types of PED, particularly those that are small, stable, or drusenoid and do not significantly affect vision, active observation may be employed. This approach, sometimes referred to as watchful waiting, involves regular monitoring without immediate intervention. The decision to observe is made by an ophthalmologist, considering that for some patients, treatment risks may outweigh benefits. Regular monitoring typically includes repeated optical coherence tomography (OCT) scans, which provide detailed cross-sectional images of the retina. This allows the ophthalmologist to track any changes in the PED’s size, shape, or the accumulation of fluid or blood.
Targeted Therapies for PED
Targeted therapies represent the primary medical and laser treatments for PED, especially those linked to wet age-related macular degeneration (AMD) or other forms of choroidal neovascularization (CNV). These treatments aim to address the abnormal blood vessel growth and fluid leakage that often accompany PED.
Anti-vascular endothelial growth factor (anti-VEGF) injections
Anti-vascular endothelial growth factor (anti-VEGF) injections are a widely used treatment. These medications block vascular endothelial growth factor (VEGF), a protein that promotes the growth of abnormal, leaky blood vessels. By inhibiting VEGF, these injections reduce fluid leakage and vessel growth, which contribute to PED. Common anti-VEGF medications include aflibercept, ranibizumab, and bevacizumab.
The procedure involves injecting the medication directly into the vitreous, the jelly-like substance in the eye. The eye is numbed with anesthetic drops, and the injection takes only a few seconds. Patients receive a series of injections, initially monthly, with frequency potentially decreasing as the condition stabilizes. Anti-VEGF therapy has been shown to reduce PED height and preserve vision.
Photodynamic therapy (PDT)
Photodynamic therapy (PDT) is another targeted treatment using a light-sensitive drug, verteporfin, activated by a non-thermal laser. The drug is injected intravenously and, once it reaches the abnormal blood vessels, a specific wavelength of light is applied to activate it. This process seals off leaky vessels, reducing fluid accumulation and stabilizing the PED. PDT is often considered for specific types of PED or in cases where anti-VEGF therapy alone is not fully effective.
Combination Therapy
A combination of anti-VEGF injections and PDT may be used. This combined approach leverages the benefits of both therapies, potentially leading to better outcomes or a reduced need for frequent injections. Combination therapy can be particularly useful in complex cases, aiming to optimize visual and anatomical results by targeting different aspects of the disease process.
Surgical Interventions
Surgical intervention for PED is uncommon, reserved for complex cases or complications. These procedures address severe consequences rather than directly treating the PED. One complication is a large subretinal hemorrhage, where significant bleeding occurs beneath the retina. In such instances, surgical techniques like vitrectomy may be considered.
A vitrectomy involves removing the vitreous gel from the eye to access the back of the retina. This can be followed by subretinal fluid drainage or pneumatic displacement of the hemorrhage. Pneumatic displacement involves injecting a gas bubble into the eye to move blood away from the central vision area, allowing it to resorb. Another rare, but severe, complication requiring surgical consideration is retinal detachment secondary to a PED, where the retina pulls away from its normal position. These surgical approaches are reserved for situations where vision is severely threatened and less invasive treatments are insufficient.