Macular Degeneration

Macular degeneration is a disease that affects the retina of the eye. It affects those above the age of fifty. Hence the condition is also called Age-related macular degeneration(AMD). It is the most common cause of blindness in those above the age of fifty.

The retina is a tissue attached to the inner wall of the eye on which images form. The macula is the central part of the retina. As a person gets old, the macula will get thinner due to various degenerative changes. This condition is called dry AMD

Wet AMD is a condition that occurs when fragile blood vessels start forming in the retina. It leads to bleeding into the macula to cause various problems. 

When these happen, that person will have problems with central vision. The side or peripheral vision will not get affected as the sides of the retina are normal.  

The early signs will be a black spot in the center of the field of vision. As the condition gets worse, the dark area will increase in size. Gradually the person will have all kinds of problems with sight in general. 

Wet AMD is a condition that occurs when fragile blood vessels start forming in the retina. It leads to bleeding into the macula to cause various problems. 

Dry AMD does not have treatments except glasses and special types of contact lenses. Persons with this will have to learn to live with it by making the necessary changes in life.

In those with dry AMD, treatments aim to prevent bleeding into the retina, especially the macula.

Types and causes of macular degeneration

There are two types of macular degeneration.

• Dry macular degeneration- It is the most common type and accounts for almost eighty percent of cases. It happens when the macula gets thin as you age. Some factors will increase your risk of it. As the macula gets thinner, some proteins called 'drusen' gets deposited in it. These cause the degeneration of the macula.
• Wet macular degeneration- It occurs when abnormal blood vessels start to form in the retina. These blood vessels are very fragile and break easily. It causes bleeding in the retina, including the macula. It may also lead to degenerative changes in the macula. 

Signs and symptoms of AMD

Most of the symptoms of AMD affect your central vision. You will not have problems with your side or peripheral vision.

Early signs of AMD

• Blurring of central vision while viewing things nearby and far off
• A shadow in the center of your field of vision
• Having large blind spots in the center of your vision 
• Straight lines may appear wavy

Late symptoms

• Distortion of vision
• Inability to see things in the center of your vision
• Having difficulty in recognizing faces
• Having problems while driving as straight lines look wavy
• Inability to distinguish between light and dark colors of the same hue
• Inability to see things in detail like textures, subtle designs, etc. It will increase your risk of falls if you are not able to see small changes in heights or depths 
• Having difficulty in seeing things under dim light
• Difficulty adjusting to change in light levels. You may take a long time to adjust when you come from a brightly lit area to a place with low light

Macular degeneration risk factors

Some of the risk factors for AMD are

• Your age- Your risk is more after the age of fifty
• Your gender- Women are more likely to have AMD than women
• Your diet- Your risk is more if you have a high-fat diet
• Your eye color- Those with light-colored eyes are more likely to have AMD
• Having family members with the disease- AMD runs in families. You are at high risk if you have close family members with the disease.
• Being a smoker-- Smokers have a very high risk of developing the disease. Your risk is also more if you have exposure to passive smoking
• Being obese- If you are obese or overweight, you are at risk
• An inactive life- AMD is less common in those who exercise regularly. Those leading an inactive life while having other risk factors are at high risk
• Having coronary heart disease- You are more at risk if you have heart disease 

Diagnosis of AMD

If you have symptoms of AMD, you will have a few tests to know the type and extent of the problem. These include

• Dilated eye examination- It helps the doctor to look into the retina in detail.
• Autofluorescence tests- It helps to identify the thickness of retinal pigments in the retina
• Ophthalmoscopy- To look into the retina, optic disk, optic nerve, etc
• Eye chart test- To measure your sight from various distances
• Fluorescein angiography- To detect wet AMD, by looking into the blood vessels in the retina after injecting a dye
• Optical coherence tomography- To know the thickness of different layers of the retina
• Tonometry- To measure the pressure in your eyes

Treatment for AMD

Macular degeneration treatments aim to control the disease rather than curing it. You will get relief from the symptoms, and the condition will not get worse over time.

You will have glasses or contact lens in the early stages. These help you to focus better to improve your sight. As the condition gets worse, you will need other treatments as well. The treatments will depend on the type of disease you have.

Treatments for dry AMD

There are no treatments to cure dry AMD. Doctors will try to improve your sight with glasses or contact lenses. Eating a healthy diet, quitting smoking, keeping your blood pressure under check, etc. can help the condition from getting worse.

You will also have counseling about 'living with AMD.' Therapists will guide you to make the best of remaining sight.

Treatment for wet AMD

You have wet AMD due to the leakage of blood into the retina. So treatments aim to prevent blood from leaking by shrinking the new blood vessels that form. 

Intravitreal injections with anti-VEGF therapy for macular degeneration

VEGF or vascular endothelial growth factors are responsible for the formation of new blood vessels in the retina. In wet AMD, the blood vessels that form are weak and fragile that will cause bleeding as they break. These medicines will also help to treat any swelling of the macula.

In anti- VEGF therapy, you will have medicines as injections into your eyes. These medicines suppress the effects of VEGF and prevent new blood vessels from forming.

You will have these injections under local anesthesia. Your doctor will use a small syringe to put the medicines into your eyes. The injections are usually painless, and the whole procedure will take only a few minutes. You will have it is an out-patient procedure, and there is no need for a hospital stay.

You will have three injections every four weeks for three months. The doctors will decide on the total number of injections depending on the medicine you are having. They will also look into how well the treatment is working. 

Some of the medicines for anti-VEGF therapy are 

• Bevacizumab
• Ranibizumab
• Pegaptanib
• Aflibercept
• Brolucizumab

Intravitreal injections are usually safe and effective. But there are a few risks like bleeding, swelling, infections, etc. of the eye. Other rare problems include increased eye pressure, formation of cataracts, retinal detachments, etc. 

Photodynamic therapy for AMD

It is one of the most effective treatments for wet AMD that do not respond to medicines.

Your doctor will inject a drug called verteporfin, through a vein in your arm. The drug slowly travels through your body and will reach the blood vessels in the macula of your eyes.

The doctor will then focus on a special laser beam on these blood vessels. The laser activates the drug, which helps to seal the blood vessels. It prevents the leakage of blood to the macula.

The treatment will take about twenty minutes to complete.outpatientore often have it as an out-patient procedure. Most of those who have the treatment will show improvement in central vision.

You will need further treatment sessions after a few months if a new blood vessel starts to form again.

You will have to avoid the sun until the drug goes out of your body, which will be about two days. Or else you may get sunburns due to its effect.

Ways to avoid AMD

There are a few things that will help you to avoid the onset of AMD. These include

• Keep your weight under control. Those who are obese are more likely to have AMD than other
• Include lots of leafy green vegetables, fruits, etc. in your diet. Avoid processed food that contains fat.
• Quit smoking if you do. Smoking can increase your risk of AMD. Even those with exposure to passive smoking are at risk
• Keep your blood pressure and blood sugar levels under control
• Exercise regularly, and stay active. AMD is more common in those who lead an inactive life 
• Use sunglasses when you are outdoors. Chronic exposure to sunlight can increase your chance. You will have to be careful if your work makes you send a long time in the sun
• Have regular eye check-ups