A common condition that is identified by loss of central vision is known as macular degeneration. Central vision allows us to see things that lie straight ahead of us. While what enables us to see on the sides is known as peripheral vision. Macular degeneration does not result in complete blindness, as it does not affect the peripheral vision. The commonness of the disease can be gauged from the fact that there are over 10 million people in the country suffering from this condition. It has also been known to be the most common reason behind vision loss in patients.
The condition occurs when the central part of the retina, known as the macula, starts wearing out. The retina is the nerve tissue placed at the back of the eye, which is responsible for sensing light. Macular degeneration is usually a result of aging. Therefore, it is often referred to as age-related macular degeneration. Although this condition does not lead to blindness, severe vision-related problems are commonly caused by this ailment. There is another type of macular degeneration that affects young adults and children and is known as juvenile macular degeneration or Stargardt disease.
Types of macular degeneration
Macular generation caused by aging is mainly categorized under two forms: dry and wet.
- Dry macular degeneration
Patients suffering from this form of the condition can have deposits, which are yellow and are known as drusen, develop in the macula. The development of some small drusen might not have any effect on the vision. However, once they start growing in size and number, they can start interfering with the vision by dimming or distorting it. Vision problems can be experienced the most while reading. When the condition starts taking a severe form, it can lead to the thinning and eventual death of light-sensitive cells present in the macula. When the condition takes an atrophic form, the patient might start having blind spots in the central vision. With time it worsens, and there can be a complete loss of central vision.
- Wet macular degeneration
Macula has blood vessels growing underneath. When these vessels start leaking fluid as well as blood into the retina, it can lead to distorted vision and straight lines can start to appear wavy. The occurrence of blind spots and eventual loss of central vision can also take place. The bleeding from the blood vessels results in the formation of a scar, which causes permanent central vision loss.
Most patients with this condition have dry macular degeneration. However, the dry form can also grow into the wet form. About 10 percent of patients with this condition have wet macular degeneration.
Symptoms associated with macular degeneration
Macular degeneration worsens with time. It is a progressive condition and in the initial stages, the person might not notice any problems with the vision. Besides, when the condition affects both eyes, any changes in the vision are also less likely to be seen.
Both dry and wet macular degeneration have their own set of symptoms which can be noticed at later stages.
Dry macular degeneration symptoms include the following:
- Distorted vision of the straight lines which appear in the vision field
- Reduced central vision
- Feeling the need to brighten the light
- Discomfort while adapting one’s vision to low lighting
- Blurred vision
- Problems with recognizing faces
The symptoms of dry macular degeneration progress slowly and do not include complete blindness. But with time, these symptoms can worsen and start affecting the daily routine activities of a person, such as driving, reading, and recognizing people. Reduced night vision is also a symptom often experienced by people with dry macular degeneration. In addition to this, dry macular degeneration patients also usually complain of strain on the eyes.
There are some symptoms of dry macular degeneration that overlap with the wet form. These include distorted vision and problems with central vision.
Besides these, patients of wet macular degeneration also experience the following symptoms:
- The appearance of a spot which is blurry in the vision field
- Haziness in the vision
- Worsening of symptoms at a rapid rate
Causes of macular degeneration
Macular degeneration, which is also known as age-related macular degeneration, is most commonly caused because of aging. However, it isn’t just aging that can lead to the condition. There are some causes, such as genetics, that can also play a role in the development of the disease. Some other factors can include:
- Poor diet
- High blood pressure
Causes of dry macular degeneration
This form of macular degeneration accounts for as many as 85 to 90 percent of the total macular degeneration cases. The cause of this form is often linked with the deposit of drusen, which is a protein. When drusen start building up under the retina, they can interfere with vision. The origin of drusen is yet to be determined. However, it is believed to be waste pieces coming from the retina. By the time a person turns 50, some hard drusen have already started building up the eyes. These cause no harm and a part of a natural process as long as they stay away from the macule, which is the central part of the retina. If the drusen start to take a large shape and reach the center of the retina, they lead to dry macular degeneration.
Drusen formed in the early stages of macular degeneration are quite small. However, they keep growing in size as the condition progresses to intermediate and then the advanced stage. By the time the condition reaches its advanced stage, the drusen have grown in number and in size, and they start blocking the oxygen supply to the eyes.
Causes of wet form macular degeneration
The wet form of macular degeneration progresses more rapidly than the dry form. This is usually a result of the formation of extra blood vessels under the macula. These extra blood vessels start leaking blood along with some other fluid in the eye resulting in damage. The origin of these extra vessels is yet to be determined. However, it is believed by some experts that these vessels are formed as a part of an attempt to remove the drusen.
Risk factors associated with macular degeneration
There have been 20 or more genes that have been found to be associated with over 50 percent cases of macular degeneration. This has helped in determining why a person can be at higher risk of developing the condition if they have a family member already suffering from it. But it isn’t just about genetics. Several other factors also come into the picture when which, when combined with the gene factor, it can increase the chances of a person to have macular degeneration.
These include the following:
This is the most common risk factor associated with the condition. Only two percent of macular degeneration patients are found to be in their 50s. But about one-third of people who are above 75 suffer from the condition.
- Ethnicity and race
The highest risk of macular degeneration is found in whites. They are followed by the Chinese and the Latino population. Africa Americans are found to be the least at risk of developing this condition. It has also been found that whites are more likely to experience complete blindness is compared to African Americans. Almost one-third of the population of whites has been found to carry the gene associated with macular degeneration. Those with light-colored eyes also have a higher risk of developing the condition. The probable cause behind this is to be believed the less ability of light-colored eyes to deflect ultraviolet rays as compared to dark-colored eyes.
Around 2/3 of macular degeneration patients are women. The condition is less relatively less prevalent in men. This can be due to a simple reason that women have a longer life than men.
- Smoking habit
A smoker is four times more likely to develop the condition as compared to a non-smoker. Smoking can directly impact the amount of oxygen supplied to various parts of the body, even to the eyes. Hence, it can put one at risk.
- High blood pressure
When a person suffers from high blood pressure, the amount of oxygen supplied to the eyes and other parts of the body becomes limited. Hence, it puts them at a greater risk of developing macular degeneration.
- Heart problems
A person who has suffered from a stroke or a heart attack or has angina is 1 ½ time more prone to the condition. People with high cholesterol problems are also at a higher risk.
There have been studies that suggest that people with a body mass index of more than 30 are at two times more prone to developing macular degeneration. However, shreds of evidence to support this are yet to be found.
- Excessive exposure to the sun
The harmful ultraviolet rays of the sun have long-term damaging effects on the eyes. Therefore, overexposure can put a person at a higher risk of developing macular degeneration.
- Certain medications
Some medications have been found to be linked with macular degeneration. These include some medications for heart problems, aspirin, etc. However, this is not certain. But one must speak to their doctor about the side-effects of this medicine before taking them.
- Alcohol consumption and diet
A diet rich in high fat and sugar content can also increase the chances of macular degeneration. Also, people who have over three alcoholic drinks a day are also at a greater risk of developing the condition.
- Surgery for cataract
People who have undergone cataract surgery are also at a higher risk of getting macular degeneration.
- Macular degeneration affecting one eye
If the condition has affected one eye, it is highly likely to affect the second eye as well.
Diagnosis for macular degeneration
Even if one is not experiencing any problems with their vision, it is always recommended to get an annual eye check-up done. If there are any changes with the vision, it is important to talk to one’s doctor about it. There can be a variety of tests recommended by the doctor to diagnose macular degeneration. For example, the doctor can use certain eye drops for the dilation of the eyes. He will then look for any signs of blood, fluid, or drusen deposits at the back of the eye. While one is getting checked for macular degeneration, the doctor can also check the field of vision of the eye by asking the patient to look at a grid. In case the grid looks broken or faded, it can point toward macular degeneration.
There are some other tests done to diagnose macular degeneration. These include:
- Fluorescein angiography
- Indocyanine green angiography
- Optical coherence tomography
Macular degeneration treatment options
A cure for macular degeneration is yet to be found. However, there are some treatment options that can make slow down the progress of the condition.
- Dry macular degeneration treatment options
When a person is diagnosed with this form of macular degeneration, they are recommended to see someone who specializes in the rehabilitation of low vision. With the help of the specialist, the patient can learn different ways to deal with the loss of vision. Surgery can also be recommended in some cases.
- Wet macular degeneration treatment options
Patients with this form are also sent to a low vision rehabilitation expert. Besides, some medication can be administered directly to prevent the growth of any new blood vessels under the retina. Photodynamic therapy is another treatment option for this form of macular degeneration.
Macular degeneration prevention tips
Although no preventive measures have been determined for the condition so far, there are certain tips that can reduce the risk of the disease. These are:
- Have a healthy diet
- Quit smoking
- Have a healthy body weight
- Exercise regularly
Diet tips for macular degeneration patients
Having a balanced and healthy diet can reduce the risk of developing macular degeneration. Foods rich in omega-3 fatty acids, antioxidants, vitamins, minerals, and nutrients that fight inflammation can help in fighting the risks of the condition and keep the eyes healthy even in old age.