Age-related macular degeneration (AMD), a common retinal condition we are frequently asked about by patients.
Let’s delve into its causes, symptoms, and treatment options to better understand this eye condition that predominantly affects older adults.
AMD primarily impacts the macula, the central part of the retina at the back of the eye, responsible for sharp and detailed vision. Over time, the macula can degenerate, leading to central vision loss or distortion. Importantly, AMD does not significantly affect peripheral vision.
Key Stages of AMD:
AMD can be broadly categorized into two forms:
1. Dry AMD:
Initial stage of macular degeneration.
Characterized by the accumulation of yellowish deposits known as drusen in the retina.
Over time, these deposits may combine, leading to retinal thinning and geographic atrophy, which can cause distortion or central vision loss.
2. Wet AMD:
A more advanced form of the disease.
Involves the growth of abnormal blood vessels beneath the retina. These vessels can leak fluid or blood, causing swelling and further damage to the retina.
It is important to note that not all cases of dry AMD progress to wet AMD.
Additionally, a variant known as Polypoidal Choroidal Vasculopathy (PCV) can present wet AMD-like changes from the onset, often leading to vision distortion.
Causes and Risk Factors related to AMD:
The exact cause of AMD is multifactorial, with the following being significant contributors:
1. Aging
AMD is predominantly seen in individuals over the age of 50.
2. Genetic Predisposition
Mutations in genes such as complement factor H (CFH) are associated with a higher risk of AMD.
3. Smoking
One of the most significant modifiable risk factors, smoking dramatically increases the likelihood of developing AMD.
4. Other Factors
High blood pressure, obesity, and prolonged sun exposure may also play a role in AMD progression.
Symptoms of AMD:
Patients with AMD often report the following symptoms:
Dry AMD: Blurred or distorted vision, difficulty reading, or the appearance of a black spot in the centre of the visual field.
Wet AMD: Rapid loss of central vision, distortion of straight lines (appearing wavy), or dark spots in the visual field due to fluid leakage or bleeding.
Diagnosing Age Related Maular Degeneration:
A comprehensive eye examination is crucial for diagnosing AMD. The following tools and techniques are commonly employed:
1. Fundus Photography
Captures detailed images of the retina to document changes such as drusen, thinning, or bleeding.
2. Optical Coherence Tomography (OCT)
A non-invasive imaging technique that provides cross-sectional images of the retina.
In dry AMD, OCT reveals drusen and retinal thinning. In wet AMD, it detects fluid accumulation and swelling, helping guide treatment. OCT Angio - further allows us to assess for retinal, choroidal vessels - non invasively using OCT.
3. Fluorescein Angiography (Optional)
Highlights blood flow and leaks in retinal vessels, used to confirm wet AMD or PCV.
Treatment Options Available for AMD:
Various retinal surgeries are recommended by eye surgeons to cure AMD, depending upon its state, whether it’s Dry AMD or Wet AMD.
Treatment for Dry AMD:
While there is no definitive cure for dry AMD, several interventions can slow its progression:
1. AREDS Supplements
Vitamin formulations, such as AREDS2, containing antioxidants, zinc, and macular pigments, help reduce the progression of dry AMD.
2. Emerging Therapies
Drugs targeting complement factor inhibition are under development and have shown promise in slowing AMD progression.
Treatment for Wet AMD:
Early diagnosis and intervention are critical for preserving vision in wet AMD. Treatments include:
1. Anti-VEGF Injections
Medications such as Ranibizumab, Aflibercept, Brolucizumab, and Faricimab are injected directly into the eye using Intravitreal injections to reduce abnormal blood vessel growth and leakage.
These drugs differ in their duration of action:
Ranibizumab: Lasts about one month.
Aflibercept: Effective for up to two months.
Brolucizumab: Provides relief for three months.
Faricimab: Lasts up to four months.
Initial treatment often involves monthly injections (loading doses) for the first three months. Subsequently, treatment frequency is adjusted based on patient response using one of the following approaches:
Pro Re Nata (PRN): Injections are administered as needed when fluid recurrence is observed.
Treat-and-Extend: Injections are given at regular intervals, gradually extending the time between treatments.
2. Sub-Macular Bleed Treatment
In advanced wet AMD, bleeding under the retina (sub-macular bleed) may occur. Treatment involves:
Removing the vitreous gel within the eye.
Injecting tissue plasminogen activator (TPA) to dissolve the blood clot.
Administering anti-VEGF therapy to prevent further damage.
Importance of Early Detection of AMD:
The success of AMD treatment heavily depends on early detection. Patients with wet AMD, identified and treated in the early stages, often experience significant vision improvement and reduced distortion. However, long-standing cases may have limited recovery potential, focusing more on halting disease progression.
To Conclude:
Age-related macular degeneration is a complex but manageable condition. With advancements in diagnostic tools and treatment modalities, the outlook for AMD patients has improved significantly. Regular eye check-ups, a healthy lifestyle, and early intervention are key to preserving vision and quality of life for those affected by AMD.
If you have any concerns about your vision or are experiencing symptoms of AMD, consult an eye care professional promptly. Together, we can work towards maintaining your eye health and preventing vision loss.
댓글