The Difference Between Wet vs Dry MD
There are many differences between wet and dry MD. From the symptoms to the speed of progression, it is imperative for many of those experiencing AMD to understand which form of AMD they actually have. In general, when comparing wet vs dry AMD, both types experience a level of central vision loss, blurry spots, and distorted vision. If you have any of these symptoms, please visit your eyecare professional immediately.
Dry macular degeneration occurs when layers of the macula get progressively thinner and functioning less and less as they do, in a process known as atrophy. In the early stages of dry MD the pigment (colour) of the macula changes. Over time, the macula becomes too thin to function properly.
The growth of tiny lumps of protein seems to contribute to the development of dry macular degeneration. The clumps of protein, known as drusen, can form and accumulate under the retina.
In time, accumulation of drusen can lead to the death of macular cells, which can cause the loss of clear, straight-ahead vision in patients with dry MD. As the clumps of drusen get larger, they can cause bleeding and scarring of the cells in the macula.
- Dry MD is more common as it is found in about 80 to 90 percent of all people with macular degeneration.
- It typically does not advance further than the presence of drusen and pigment discoloration.
- It tends to progress more slowly than wet AMD.
- Dry MD could progress to wet macular degeneration.
Symptoms of Dry MD
- Increased difficulty with night vision
- Printed texts appearing blurry
- Visual distortions, such as straight lines appearing wavy
- Reduced central vision in one or both eyes
- Lower sensitivity to colours
In wet macular dengeneration, abnormal blood vessels grow in the choroid layer laying behind the retina, in a condition doctors call “choroidal neovascularization (CNV).” The newly formed blood vessels are weak; they can leak fluid, blood, and lipids. The leaked fluids can seep into the layers of the retina, including the macula. There, the fluids can interfere with the function of retinal cells and can even scar the macula.
Because of the formation of the new blood vessels, eye doctors sometimes refer to wet macular degeneration as neovascular AMD. Some eye care professionals refer to it as “exudative AMD,” because it involves the exudation (leakage) of blood and fluid from the newly formed blood vessels. Pressure from fluid leakage causes the macula to bulge or even lift up from its normally flat position, which distorts or even destroys central vision. Vision loss can be rapid and severe in these cases.
In wet macular degeneration, the blood and fluid under the macula can cause the patient to see one or more dark spots in the center of their vision. The macula is no longer smooth, which can cause straight lines to look wavy. Wet macular degeneration rarely affects the patient’s peripheral, or “side,” vision. Many patients with wet MD do not notice any changes in their vision, which makes periodic eye examinations extremely important for patients at high risk for wet macular degeneration.
Risk Factors for Developing CNV
Certain factors can increase a patient’s risk for developing CNV associated with wet macular degeneration. These risk factors include:
- More than five drusen
- Large drusen
- Pigmental clumping – clumps of drusen that accumulate within and beneath the retinal pigment epithelium
- Systemic hypertension – high blood pressure within the arteries that carry blood from the heart to the rest of the body
Once CNV develops in one eye, with or without vision loss, the other eye is at higher risk for developing the condition. This is especially true when the individual has all four risk factors for CNV.
- Wet macular degeneration is less common as it occurs in about 10 to 20 percent of individuals with AMD.
- However, between wet vs dry MD, wet macular degeneration is much more serious as it accounts for about 90 percent of all cases of severe vision loss caused by MD.
- Vision loss tends to occur more quickly for people with wet macular degeneration than for those with dry MD.
- It is also called exudative AMD or neovascular AMD because of the exudation of fluid and blood from blood vessels.
Symptoms of Wet MD
- Symptoms quickly getting worse after you notice initial warning signs
- Decreased colour brightness
- Gray or blurry spot in the middle of your vision
- Visual distortions
- Overall hazy vision
Available Assistive Technology
Many successful eSight users live with central vision loss, which makes eSight a popular choice for those diagnosed with wet or dry MD. eSight is a low vision eyewear device, worn like glasses, that functions by stimulating synaptic activity from the remaining photoreceptor function of the user’s eyes.
Using a cutting edge camera, smart algorithms and high resolution screens, the assistive technology can provide the brain with increased visual information to naturally compensate for gaps in the user’s field of view. As a result, eSight makes clearer vision possible, resulting in enhanced vision of up to seven lines on a doctor’s eye chart.
eSight Users with MD
Seven out of 10 users living with MD experience significantly enhanced vision after trying eSight. eSight users like David Lee have been able to resume their favourite hobby of curling, and even win their curling provincial playdowns.
Although there are other technological options available to enhance vision for those with wet or dry MD, eSight is one of the only ones that boasts substantial mobility for its users.