Macular degeneration, a condition leading to the loss of central vision, is primarily managed through non-surgical treatments. However, surgical options do exist, though they are reserved for specific circumstances and advanced stages of the disease. These interventions fall into two main categories: devices designed to enhance vision in eyes with severe, stable loss and procedures aimed at managing acute complications from the aggressive form of the disease.
Non-Surgical Standard Treatments
The first line of defense against vision loss from macular degeneration involves pharmacological and nutritional strategies, which differ based on the form of the disease. For neovascular or “wet” macular degeneration, the standard treatment involves regular intravitreal injections of Anti-Vascular Endothelial Growth Factor (Anti-VEGF) medications. These drugs, which include agents like ranibizumab, aflibercept, and bevacizumab, work by blocking the protein that promotes the growth of abnormal, leaky blood vessels beneath the retina. Early and consistent Anti-VEGF treatment can stabilize vision and, in many cases, lead to significant visual improvement.
For the more common atrophic or “dry” form of the disease, there are currently no treatments to reverse vision loss, but progression can be slowed. Patients with intermediate or advanced dry macular degeneration in one eye are often advised to take nutritional supplements, known as AREDS2. This supplement contains vitamins C and E, zinc, copper, and the antioxidants lutein and zeaxanthin. Taking the AREDS2 formulation may reduce the risk of the disease advancing to the late stage by approximately 25% over a five-year period.
Surgical Interventions for Macular Degeneration
When non-surgical treatments have reached their limit, particularly in advanced cases, specific surgical options may become available. One primary surgical approach is the implantation of a Vision Enhancement Device, specifically the Implantable Miniature Telescope (IMT).
The IMT is implanted into one eye, replacing the natural lens during a procedure similar to cataract surgery. It functions as a Galilean telescope, using a system of lenses to magnify the image two to three times its original size. This magnification projects the image onto the surrounding, healthier areas of the retina, bypassing the damaged macula. The non-implanted eye is left to maintain peripheral vision, creating a dual-vision system where one eye handles detailed, central tasks and the other handles orientation.
Another surgical intervention manages severe complications arising from advanced wet macular degeneration. A vitrectomy procedure may be performed to clear the eye of dense hemorrhage, such as a vitreous or large subretinal hemorrhage. This procedure involves removing the vitreous gel and accumulated blood that can be toxic to the delicate retinal tissue. Surgeons sometimes use a clot-dissolving agent, such as tissue plasminogen activator (tPA), injected into the area to help break down the blood clot before removal. The goal is not to cure the underlying disease but to remove the blood and scar tissue acutely obstructing vision.
Eligibility, Risks, and Post-Operative Expectations
The criteria for receiving a surgical device like the Implantable Miniature Telescope are strict. Candidates must typically have stable, bilateral, end-stage dry macular degeneration with a specific range of poor vision, such as 20/160 to 20/800. Patients must not have active wet macular degeneration and should not have had prior cataract surgery in the eye selected for the implant. A thorough pre-operative evaluation, including a simulation with an external telescope, is required to ensure the patient is motivated and likely to benefit from the magnification.
Like any intraocular surgery, there are risks. The most common adverse events associated with the IMT procedure include inflammatory deposits on the device and a temporary or sustained increase in intraocular pressure. More serious, though less frequent, risks involve corneal edema, sometimes severe enough to require a corneal transplant. There is also a small risk that the surgery could worsen vision instead of improving it.
Post-operative expectations must be carefully managed, as the surgery does not restore normal, youthful vision. Patients must commit to a visual rehabilitation program with low-vision specialists and occupational therapists. The telescopic implant improves the ability to perform central vision tasks, such as recognizing faces or reading large print, but the magnified image results in a reduced field of view in the implanted eye. The overall outcome is an improvement in the quality of life and functional vision, requiring the patient to learn how to seamlessly switch between the magnified central vision in one eye and the wider peripheral vision in the other.