Age-related macular degeneration (ARMD) is a dreadful ocular disease mainly affecting people above 50 and is the result of damage to the central area of the retina called the macula, which is responsible for reading and driving vision. In conversation with THE HEALTH PIONEER, well-known Ophthalmologists Dr. Rohan Chawla and Dr Mahipal Singh Sachdev throw insight into the disorder and warn that as diagnosis usually occurs in later stages when a visual loss has already occurred, no effective treatment can be given. Hence, early detection is the key to ensuring the quality of life of the eyes.
ARMD causes central irreversible vision loss in the older population, resulting in disability and significantly affecting the quality of life. It is caused due to age, genes, smoking, high blood pressure or high cholesterol, obesity, eating lots of saturated fat, being light-skinned, being female, and having a light eye color.
In Wet form, blood vessels grow from underneath your macula. These blood vessels leak blood and fluid into your retina. Your vision is distorted so that straight lines look wavy. You may also have blind spots and loss of central vision. These blood vessels and their bleeding eventually form a scar, leading to permanent loss of central vision. The wet form of macular degeneration is a leading cause of permanent vision loss. If it’s in both eyes, it can hurt your quality of life. Wet macular degeneration may need repeated treatments. Test your vision regularly, and follow your doctor’s advice.
Most people with macular degeneration have a dry form, which may lead to a wet form. Only about 10% of people with macular degeneration get the wet form.
It is extremely important for people above the age of 50 years to get regular dilated ophthalmic examinations done. The risk factors associated with ARMD are advancing age, genetic factors, cigarette smoking, comorbidities such as cardiovascular disease, hypertension, female gender, hypercholesterolemia, obesity, family history, light irides, etc.
Early on, you might not have any noticeable signs of macular degeneration. It might not be diagnosed until it gets worse or affects both eyes. But if you feel that your vision is getting blurry, and it is hard to read fine print or drive, go to an eye doctor as soon as possible.
If you are above 50 years of age, your doctor can check you for ARMD when you see them for a routine eye exam and have your eyes dilated. They'll test your vision and also examine your retina -- a layer of tissue at the back of your eye that processes light. They'll look for tiny yellow deposits called drusen under the retina. It's a common early sign of the disease.
Your doctor may also ask you to look at an Amsler grid -- a pattern of straight lines that's like a checkerboard. If some of the lines appear wavy to you or some of them are missing, it could be a sign of macular degeneration. ARMD can also be Early or Advanced, the advanced form further divided into atrophic or neovascular variants. The neovascular form is responsible for more than 90% of the vision loss associated with ARMD and causes swelling and fluid accumulation in the retina.
If your doctor finds ARMD, you may have a procedure called angiography or one called OCT. In angiography, your doctor injects dye into a vein in your arm. They take photographs as the dye flows through the blood vessels in your retina. If there are new vessels or vessels leaking fluid or blood in your macula, the photos will show their exact location and type. OCT is able to see fluid or blood underneath your retina without dye.
It’s important to see your eye doctor regularly to find signs of macular degeneration early. Treatment can slow the condition or make it less severe.
According to a study, India has 23.5 per cent of global blindness, which suggests that the surveillance of various risk factors and controlling them is the need of the hour so that we can prevent this disease at an early stage before causing significant visual impairment.
The earliest symptoms of ARMD include difficulty near vision, wavy or distorted appearance of letters while reading, the appearance of black spots in the visual field, lack of vision improvement with glasses, loss of contrast, slow recovery of vision after coming from bright light, etc.
At present, there are more than 70 million people above the age of 60 years in India. The improving life expectancy means that the burden of this disease is imminent in the near future. The estimated number of people above the age of 60 years are expected to reach about 180 million by the year 2026 and so is the expected increase in age-related degenerative retinal disease. But these changes are not easily identifiable unless a thorough eye examination is carried out by an ophthalmologist.
The neovascular form however requires special injections into the eye known as anti-VEGF (vascular endothelial growth factor). However, once the swelling subsides, the consequent scarring distorts the retinal architecture. Therefore, a prompt diagnosis, early intervention is the key to preserving good vision in ARMD. Regular screening for ARMD should be conducted in people above 50 years including periodic dilated fundus examination.
Because usually women live longer than men, we find there are more women suffering from ARMD than men.
—Dr Mahipal Singh Sachdev.
Professor in Ophthalmology and Padamashri Awardee
Senior Consultant, Chairman and Medical Director,
Centre For Sight Group of Eye Hospitals
There are two main types of age-related macular degeneration. One is a dry form in which people's eyes may have yellow deposits, called drusen, in their macula. A few small drusen may not cause changes in your vision. But as they get bigger and more numerous, they might dim or distort your vision, especially when you read. As the condition gets worse, the light-sensitive cells in your macula get thinner and eventually die. In the atrophic form, you may have blind spots in the center of your vision. As that gets worse, you might lose central vision.
Preventive measures to stop ARMD progression include cessation of cigarette smoking, blood pressure control with anti-hypertensives, and reduction in cholesterol levels. Eat green leafy vegetables and carrots for better health of the eyes. There are certain formulations of eye vitamins containing antioxidants and Omega 3 fatty acids that have shown to retard the progression of ARMD.
It is estimated that a total of 30-50 million people are suffering from ARMD world over, and this number is rising dramatically as age advances. According to the World Health Organization, 288 million people will suffer from ARMD by 2040, if it remains uncontrolled and untreated. Dry ARMD is more prevalent than wet ARMD in India.
—Dr Rohan Chawla.
Assistant Professor of Ophthalmology,
Dr. RP Centre for Ophthalmic Sciences, AIIMS, Delhi
treatment options
There’s no cure for macular degeneration. Treatment may slow it down or keep you from losing too much of your vision. Your options might include:
Anti-angiogenesis drugs:
These medications -- aflibercept (Eylea), bevacizumab (Avastin), faricimab-svoa (Vabysmo), pegaptanib (Macugen), and ranibizumab (Lucentis) -- block the creation of blood vessels and leaking from the vessels in your eye that cause wet macular degeneration. Many people who’ve taken these drugs got back some vision that was lost. You might need to have this treatment multiple times.
Laser therapy: High-energy laser light can destroy abnormal blood vessels growing in your eye.
Photodynamic laser therapy: Your doctor injects a light-sensitive drug -- verteporfin (Visudyne) -- into your bloodstream, and it’s absorbed by the abnormal blood vessels. Your doctor then shines a laser into your eye to trigger the medication to damage those blood vessels.
Low vision aids: These are devices that have special lenses or electronic systems to create larger images of nearby things. They help people who have vision loss from macular degeneration make the most of their remaining vision.
Is New Gene Therapy a ray of hope?
Researchers from Trinity College Dublin have developed a new gene therapy approach that shows promise for treating the dry form of (ARMD). The gene therapy, ophNdi1, developed by the team in Trinity’s School of Genetics and Microbiology, is the first of its kind to directly target mitochondrial function in cells that are malfunctioning in ARMD.
In adults, many diseases of aging have been found to have defects of mitochondrial function, including ARMD.
Mitochondria are known as the “powerhouses” of the cell because they manage the production of energy but their performance dips greatly in dry ARMD and this is linked to a deterioration in sight.
The new gene therapy cleverly uses a virus to access the cells that are suffering and deliver the code needed to give the failing mitochondria a lifeline, enabling them to generate extra energy and continue to function in supporting the vision.
The therapy has shown benefits in multiple models of dry ARMD.
Professor Jane Farrar, the senior author, said, “Critically, this study provides the first evidence in models that directly modulating bioenergetics in eye cells can provide benefit and improve visual function in dry ARMD. In doing so, the study highlights the energy powerhouses of the cell, mitochondria, as key targets for dry ARMD.”
Dr. Sophia Millington-Ward, first author and research fellow in Trinity’s School of Genetics and Microbiology, said, “The novel gene therapy targeting cellular energy, or mitochondrial function, that we explored for dry AMD consistently provided benefit in the model systems tested.”
