How successful are injections for wet macular degeneration?
Wet macular degeneration is an age-related disease.
Clinical studies have documented a definite success of intraocular (into the eye) injections for wet macular degeneration. After one year of intraocular therapy, the vision improved by about 25-34% compared with 5% in those who did not choose intraocular injections.
Avastin (bevacizumab), Lucentis (ranibizumab), and Eylea (aflibercept) are the medications used for the treatment of wet macular degeneration. These are injected into the eye every four weeks for around one year. After one year, the frequency at which you require injections may be decided by your eye doctor.
These injections have shown to halt the ongoing vision loss and, in some cases, even improve the vision. The therapy is most effective if started between 7 and 21 weeks of the onset of symptoms.
In many studies, improvements were consistent and maintained for two years after starting the treatment. A continued treatment showed an improvement in the retinal structure and reduced retinal scarring in the various scans conducted.
What is wet macular degeneration?
The retina is a thin layer at the back of the eye. It contains the receptors (cells) for light and color detection. These cells trigger the nerve signals for image formation in the brain. The retina plays a central role in our vision.
The macula is the oval area near the center of the retina where the visual receptor cells are concentrated. The macula is involved in visual sharpness and color vision. Any damage to the macula can cause permanent blindness.
Wet macular degeneration is an age-related disease. It may be seen after 50 years of age. In this disease, there is an abnormal growth of blood vessels over the retina. These blood vessels leak fluid, lipids, and blood all over the retina. The leaks damage the retinal structure and cause scarring of its layers. People with a damaged retina experience the following issues:
- A gradual loss of vision
- Haziness when they see
- Distorted images
- New blind spots or an increase in the number of the blind spots
- Complete blindness is rare, but there is a reduction or loss of central vision over time
The main culprit behind the blindness seen in macular degeneration is the growth of abnormal blood vessels over the retina and macula. These vessels grow because of a substance called vascular endothelial growth factor (VEGF) in the retina. The VEGF in the retina may be produced in response to a compromised blood supply causing poor oxygen supply to the cells within.
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What conditions can put you at a risk of wet macular degeneration?
The following conditions predispose the person to a risk of wet macular degeneration:
Age: After the age of 50 years, a person is at a high risk of the condition.
Ethnicity: It appears to be more prevalent in Caucasians.
Genetics and family history: Individuals who have a family member who has macular problems are at risk of macular degeneration. Certain genetic changes are known to put you at risk of macular problems.
Smoking: Smoking increases the risk of macular damage. Smokers have a rapid progression to blindness and have poorer treatment response. This is because the nicotine in cigarettes is toxic to the eye cells.
Alcohol use: More than three drinks per day is associated with an increased risk of macular degeneration.
Cardiovascular disease: A history of a stroke or heart disease may put you at an increased risk of wet macular degeneration. Individuals with diabetes also have an increased risk of wet macular degeneration.
Acquired immunodeficiency syndrome (AIDS): Patients with AIDS have been reported to have a 1.75-fold increase in the incidence of macular degeneration.
Chronic myeloproliferative diseases: Patients with chronic myeloproliferative diseases (diseases of the blood and bone marrow) have an increased risk of macular degeneration. These include:
- Essential thrombocythemia (below normal platelets, causing a tendency to bleed)
- Polycythemia vera (abnormally high red blood cells)
- Myelofibrosis (scarring of the bone marrow causing low blood cell production in the bone marrow)
Medications: Aspirin and certain drugs used in heart conditions (nitroglycerin and beta-blockers) may put you at a high risk of macular disease, although this claim needs further studies for validation.
Do intraocular drugs have any side effects?
Drugs injected in the eye have certain side effects. However, it must be remembered that in most cases, the benefits outweigh the risks.
- Eye pain and bleeding into the eye
- Retinal detachment (separation of the retinal membrane from the blood vessels of the eye)
- Increased floaters (moving spots in the vision)
- Eye infection
- Increased eye pressure that can adversely harm the optic nerve
- Endophthalmitis (a serious condition that can cause severe eye swelling and blindness if not treated)
- Increased risk of stroke and blood clots