What is Age-Related Macular Degeneration? Symptoms, Causes & Treatment

Age-related Macular Degeneration is a condition that affects the eye’s central vision. It affects the macula, which is the central part of the retina and is responsible for central vision. This condition affects only central vision and does not impact peripheral vision.

In the US alone, around 20 million people are affected with macular degeneration. By 2040,  itsis expected, thatAMD is going to affect almost 288 million people worldwide.

Since it is an age-related condition, macular degeneration mostly affects people older than 50 years.

Types and stages of Macular Degeneration

TYPES OF MACULAR DEGENERATION
Dry or atrophic	Wet or exudative
Drusen, yellow protein deposits, develops under the macula, dries and thin the macula. Gradually, overtime the person suffers from vision loss.	As the name suggests, in this type blood vessels form under the retina and macula and leak fluid and blood. The affected person rapidly suffers from vision loss.

There are three stages of Macular Degeneration:

In the early stage, slight changes in the macula occur, In the intermediate stage, vision turns blurry, and in the advanced or final stage, there is a complete loss of central vision.

Causes of Macular Degeneration

There are several risk factors that may contribute to the development of macular degeneration:

1. Family history of age-related macular degeneration (AMD)
2. Conditions like diabetes or hypertension
3. History of smoking, obesity
4. Nutritional deficiency
5. Taking a diet rich in saturated fats
6. More common in white people
7. Trauma or injury to the eye.

Symptoms of age-related macular degeneration

The primary role of the macula is to analyze the objects and send signals from the optic nerve of the eyes to the brain. However, in cases where the macula is damaged, the optic nerve cannot transmit signals to the brain

1. Difficulty visualizing in low light
2. Blurry vision
3. Difficulty distinguishing between colors
4. Dark spots in the field of vision
5. Straight lines appearing differently
6. Loss of central vision

The loss of central vision can directly hamper the ability to carry on with daily activities such as reading, driving, cooking, and other household chores.

AMD patients sometimes also encounter Charles Bonnet syndrome, a syndrome where patients experience visual hallucinations.

Diagnosis of AMD

In order to diagnose the condition, the doctor examines changes in the retina and the macula and recommends certain tests to determine the extent of vision loss.

1. Visual acuity test: It is a basic test that measures the ability to visualize at various distances. 
2. Test using Amsler grid: The Amsler grid consists of straight grid lines along with a central large dot. The test involves viewing and identifying grid lines that appear blurry and wavy.
3. Dilation test: The doctor applies eye drops to dilate the pupils and examines the eyes for the presence of any damage along with symptoms.
4. Fluorescein angiography: In this test, the doctor injects fluorescein, a yellow dye, into the arm vein, and a camera tracks its movement in the eye blood vessels. This test determines the presence of leakage under the macula.
5. Optical coherence tomography: Optical coherence tomography is an imaging procedure that takes images of the retina and the macula.
6. Optical coherence tomography angiography: Optical coherence tomography angiography is an advanced version of fluorescein angiography. In this, laser light reflection is used instead of fluorescein dye to determine blood flow in the eye. This technique enables the production of 3D images of blood flow.

Management of age-related macular degeneration

The existing treatment strategies are only helpful in managing the condition, slowing the disease progression, and improving symptoms since there is no cure for AMD.

1. Nutritional supplement: Supplements rich in vitamins such as vitamin C, along with vitamin E, minerals such as zinc and copper, and antioxidants such as lutein and zeaxanthin slow the progression of AMD.
2. Anti-vascular endothelial growth factor (anti-VEGF) injection: Doctors give anti-VEGF injection shots in the vitreous region to improve vision since these injections block VEGF production. Examples are Aflibercept, Bevacizumab, and Ranibizumab.
3. Photodynamic therapy: In this therapy, the eye care provider aims to destroy blood vessels by employing a combination of a light-sensitive drug and laser therapy.
4. Submacular surgery: This is a surgical option in which a healthcare provider removes abnormal blood vessels and blood from the macular region of the eye.
5. Retinal translocation: In this procedure, the eye care specialist detaches and translocates the retina to ensure that the macula remains away from the abnormal blood vessels.
6. Acupuncture: It is an alternative treatment option where the insertion of tiny needles at specific points helps improve blood flow to the eye.
7. FDA-approved drugs: Avacincaptad pegol and pegcetacoplan are FDA-approved drugs that slow down the development of AMD by inhibiting the immune system’s attack on the retina. These drugs are effective in dry AMD.

Stem cell therapy for macular degeneration

With conventional treatment strategies limited to managing the condition, stem cell therapy has provided new ease of life because it can replace the damaged cells and restore the loss of vision.

Stem cell for age-related macular degeneration differentiate and proliferate into specialized types of retinal cells, such as retinal pigment epithelial cells (RPE) and photoreceptors. They replace the cells damaged due to AMD in the eye and restore eye functions. They also exert a positive impact on the retina and improve visual function.

Secretion of neurotrophins

Stem cells secrete neurotrophins such as Brain-Derived Neurotrophic Factor (BDNF) and fibroblast growth factor, which inhibit apoptosis of photoreceptor cells and restore retinal function. This is because, during AMD, photoreceptor cells and retinal functions are lost.

Reduction of retinal inflammation

In order to reduce inflammation in the retina, stem cells decrease activation of the microglia, which in turn reduces retinal inflammation.

Inhibition of neuronal apoptosis

Certain anti-apoptic proteins and transcription factors increase after implantation of stem cells, which is necessary to inhibit the process of retinal apoptosis. 

Benefits of stem cell therapy

1. Visual activity improvement

2. Delay and slowing of disease progression

3. Reduction in scarring and pain

4. Reduction in figures

5. Enhancement of blurry vision

Conclusion

Stem cell therapy in the retinal field has proven to be essential in Macular Degeneration treatment. With stem cell therapy, it is possible to protect and improve the central vision. This is because stem cells not only replace the damaged retinal cells but also restore visual function, which is necessary in the management of AMD.

Therefore, retinal regenerative therapies are making steady progress and are expected to become greater with technological innovations in the ophthalmic field.

FAQs

Q: Define macular degeneration.

Age-related macular degeneration is a condition that impacts the eye’s central vision. It affects the macula, which is the central part of the retina and is responsible for central vision. This condition affects only central vision and does not impact peripheral vision.

Q: What are the symptoms associated with macular degeneration?

The symptoms of macular degeneration are difficulty visualizing in low light, blurry vision, difficulty distinguishing between colors, dark spots in the field of vision, straight lines appearing differently, and loss of central vision.

Q: Explain the role of stem cell therapy in macular degeneration.

Stem cell for macular degeneration differentiate and proliferate into specialized types of retinal cells, such as retinal pigment epithelial cells (RPE) and photoreceptors. They replace the damaged cells damaged due to AMD in the eye and restore eye functions.

Q: List the benefits of stem cell therapy in AMD.

The benefits in AMD are improved visual activity, delay and slowing of disease progression, reduction in scarring and pain, reduction in figures, and enhancement of blurry vision.