Key Differences Between Wet AMD and Dry AMD

Understanding the Differences Between Wet and Dry AMD

Age-related macular degeneration (AMD) is an eye disease that affects central vision. It occurs when the macula, which is responsible for sharp central eyesight, is damaged over time by the accumulation of waste products from retina cells. AMD has two main forms – dry AMD and wet AMD.

Dry AMD is the early stage that may eventually advance to wet AMD in some cases. Understanding the distinctions between these two types is important for getting the right diagnosis and treatment.

Dry AMD

Dry AMD makes up about 85-90% of AMD cases. It develops from the gradual buildup of yellowish deposits called drusen under the retina over many years. Drusen are composed of lipids, proteins, and waste byproducts from retinal cells.

As drusen accumulate, they cause thinning and drying of the macula’s light-sensitive cells. This impairs central vision used for activities like reading, driving, and recognizing faces.

Dry AMD has three stages:

• Early: Small drusen form with little vision loss.
• Intermediate: Drusen grows larger and vision worsens.
• Advanced: The macula thins extensively, creating blurred central vision.

Vision loss is usually gradual with dry AMD. Most people progress slowly from early to intermediate, which may take years. Not everyone advances to the advanced stage of geographic atrophy.

Wet AMD

Wet AMD occurs when abnormal blood vessels behind the retina start growing under the macula. These fragile vessels often leak fluid or blood, causing rapid damage to macula cells.

This form accounts for only about 10-15% of AMD but causes the most severe vision loss. Abnormal vessel growth is likely the body’s response to poor macular blood flow from accumulating drusen.

There are different forms of wet AMD:

• Occult: Leakage under macula with vision changes.
• Classic: More defined leaky vessels and central vision loss.
• Retinal pigment epithelial detachment: Macula separates from its supporting tissue layer.

Wet AMD can develop abruptly, sometimes overnight. Without treatment, it often leads to permanent central vision damage within months. But it can occasionally be stabilized if caught early.

Key Differences Between Wet and Dry AMD

Understanding how wet and dry AMD differ allows for faster diagnosis and more effective management. Some of the key distinctions include:

Speed of Progression

Dry AMD develops incrementally over years, so vision loss is gradual. People may not notice changes in daily activities for some time. Wet AMD progresses exponentially faster, sometimes impairing central vision within weeks or months if left untreated.

Cause

Dry AMD stems from waste buildup under the retina that damages macula cell function. Wet AMD occurs when abnormal blood vessels invade the macula, often due to poor blood flow from accumulated drusen.

Symptoms

Dry AMD causes blurred central vision or needing more light to see. Wet AMD additionally causes straight lines to appear warped or crooked and a dark or blank spot covering central vision.

Risk Factors

Advancing age is the top risk factor for both forms of AMD. However, smoking increases risk more significantly for wet AMD. Certain genes and obesity also raise wet AMD risk higher.

Diagnosis

Both forms are diagnosed with a comprehensive eye exam checking visual acuity, dilated eye appearance, and imaging tests. Optical coherence tomography (OCT) and angiography can detect abnormal blood vessels indicative of wet AMD.

Treatment

No treatment can reverse or halt dry AMD, only managing symptoms. Wet AMD is treated aggressively with frequent eye injections of drugs that block vessel growth factors.

Prognosis

Dry AMD results in mild to moderate vision loss over many years. Without treatment, wet AMD commonly causes profound central vision loss and blindness within months after onset.

Who Gets Wet vs. Dry AMD?

Advanced age remains the top risk factor for developing both forms of AMD. But other factors may indicate whether someone is more prone to dry vs. wet AMD.

Gender

Women appear to be at greater risk for developing dry AMD by a slight margin. However, men have a somewhat higher risk of progressing to wet AMD. Hormonal differences may play a role in these disparities.

Smoking

Smoking strongly increases the risk of wet AMD but shows less consistent links with dry AMD progression. Chemicals in cigarette smoke damage blood vessels and macula blood flow, making abnormal vessel growth more likely.

Genetics

Genes play a significant role, especially for wet AMD. Those with family history of wet AMD have higher risk. Certain gene variants regulating inflammation and angiogenesis increase susceptibility.

Ethnicity

Advanced AMD is more common in Caucasian populations, especially wet AMD. Hispanics and African-Americans have lower rates of progression to advanced AMD stages.

Additional Factors

Obesity, diet high in saturated fats, hypertension, and cardiovascular disease correlate more strongly with wet AMD development. Protective factors like omega-3 fats, antioxidants, and physical activity relate more to reducing dry AMD risk.

Preventing Progression to Wet AMD

Unfortunately, no proven treatment exists to prevent or slow the progression of dry AMD currently. However, emerging research shows certain lifestyle and dietary changes may help lower the risks of advancing to wet AMD.

Quit Smoking

Since smoking strongly increases wet AMD risk, quitting can be very protective. It’s never too late to reap benefits – even those who quit later in life reduce their chances of developing aggressive wet AMD.

Eat an AMD-Friendly Diet

Consume plenty of leafy greens, fish, nuts, whole grains, and fruits packed with antioxidants and omega-3s. Avoid processed foods high in saturated/trans fats, sugars, and excess salt that may promote inflammation.

Maintain Healthy Weight

Carrying extra weight strains the vascular system, potentially reducing macular blood flow. Losing even a modest amount of weight takes pressure off blood vessels and lowers wet AMD conversion risk.

Exercise Regularly

Aim for at least 150 minutes per week of moderate physical activity. Aerobic exercise improves vascular health and retinal oxygenation, potentially protecting vision from AMD progression.

Control Cardiovascular Factors

Work with your doctor to properly manage conditions like high blood pressure, high cholesterol, and diabetes. Optimizing vascular health ensures sufficient blood flow to the macula.

Take a Targeted Supplement

The AREDS 2 study found supplements with specific vitamin/mineral doses reduced risk of dry AMD progressing to wet AMD by around 25%. Check with your eye doctor to see if one is recommend for you.

Get Regular Eye Exams

Seeing an ophthalmologist at least annually allows tracking AMD progression closely. Early wet AMD detection and treatment can help retain more vision.

Living with Wet or Dry AMD

Being diagnosed with any form of macular degeneration is frightening, but ample support exists to maximize your remaining vision.

Use Low Vision Aids

Devices like telescopic glasses, magnifiers, and electronic magnification aids enable you to utilize and preserve more of your peripheral vision when the macula is damaged.

Modify Your Surroundings

Improve lighting with task lamps and nightlights to reduce glare and shadow. Increase text size on phones and computers. Organize closets/cabinets to easily identify items.

Learn New Skills

Occupational therapists teach techniques to safely perform daily tasks despite vision impairment. Specialists called Certified Vision Rehabilitation Therapists can maximize your existing vision.

Join a Support Group

Connecting with those experiencing similar vision changes from AMD provides emotional support and practical coping strategies. The AMD Alliance offers online and in-person groups.

Explore Your Options

Depending on the type and severity of AMD, options like laser surgery, drugs, stem cell therapy, or telescopic/bionic lens implants may help certain people. See what your ophthalmologist recommends.

Though AMD treatment remains limited, don’t abandon hope for stabilizing your vision. Monitoring AMD progression and utilizing all available resources allows you to adapt and retain visual function.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.