Before deep diving into Age-related Macular Degeneration, also known as AMD, we need to understand what Macula is.
Macula
The macula is a tiny area of your retina which is very important for seeing detail, colour and things directly in front of you. When light enters your eye, it is focused on your retina at the back of your eye. The retina has many layers, but the most important for vision is a layer made up of cells called photoreceptors.
Photoreceptors are cells which are sensitive to light. Retina Macula Optic Nerve Vitreous gel Iris Cornea Pupil Lens 11 The macula contains a few million specialised photoreceptor cells called cone cells.
These cone cells work best in bright light and allow you to see fine detail for activities like reading, writing, and recognising colours. When someone develops AMD, the cone cells in the macular area become damaged and stop working as well as they should.
The peripheral retina is further away from the central macula. It is mainly made up of the other type of photoreceptors called rod cells. They allow us to see when light is dim and provide peripheral vision (also known as side vision) outside of the main line of sight. AMD does not affect the peripheral retina, meaning that side vision remains good. AMD does not cause you to lose all your sight.
Age-related Macular Degeneration (AMD)
Age-related macular degeneration is the most common cause of severe loss of eyesight among people aged 50 and older. Only the centre of vision is affected by this disease. It is important to realise that people rarely go blind from it.
AMD affects the central vision and, with it, the ability to see fine details. In AMD, a part of the retina called the macula is damaged. In advanced stages, people lose their ability to drive, see faces, and read small print. In its early stages, AMD may have no signs or symptoms, so people may not suspect they have it.
Types of Age-Related Macular Degeneration and Their Causes
Macular degeneration is a disease in which a breakdown begins in the light-sensitive cells lining your retina's back. It usually affects vision at the center of your field of vision, such as when you read or drive. There are two types of age-related macular degeneration: Dry and Wet.
Dry:
This is the most common type. The damage to the vital membrane support under the retina is believed to contribute to dry age-related macular degeneration. The loss of vision in this condition is slow and gradual. It's unknown, but genetic and environmental factors are considered to play a role.
Wet:
It is the most common cause of severe loss of vision. Wet AMD happens when abnormal blood vessels start to grow beneath the retina. They leak fluid and blood—called "wet AMD"—and can create a large blind spot in the center of the visual field. Though this type is less common, it usually leads to more severe vision loss in patients than dry AMD.
Symptoms of Age-Related Macular Degeneration:
Everyone can have different symptoms, but usually, the first thing you’ll notice is that it’s harder to see details, such as small print. You may find that your vision has a small, blurred area in the center. Straight lines may look distorted or wavey. You may also find that you are sensitive to bright light.
AMD can make things like reading, watching TV, driving, or recognising faces difficult.
- Other symptoms include:
- Seeing straight lines as wavy or crooked
- Objects to look smaller than usual.
- The colours seem less bright than they used to.
- Hallucinations
AMD is not painful and does not affect the appearance of your eyes.
Sometimes, AMD may be found during a routine eye test before you have symptoms.
Diagnosis of Age-related Macular Degeneration:
In addition to a complete medical history and eye exam, your eye doctor may perform the following tests to diagnose age-related macular degeneration:
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Visual acuity test: This standard eye chart test measures vision ability at various distances.
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Pupil dilation: The pupil is widened with eye drops to allow a close-up examination of the eye’s retina.
- Fluorescein angiography: It is used to detect wet age-related macular degeneration. It involves having a special dye injected into a vein in the arm. Pictures are taken as the dye passes through the blood vessels, helping the doctor evaluate whether the blood vessels are leaking.
- Amsler grid: Used to detect wet age-related macular degeneration, this test uses a checkerboard-like grid to determine if the straight lines in the pattern appear wavy or missing to the patient. Both indications may signal the possibility of age-related macular degeneration.
Treatment for Age-related Macular Degeneration
Dry AMD:
Although there is no cure for AMD, treating dry AMD consists of managing the symptoms. However, there are some vitamins that many people with AMD take as supplements that may help reduce the impact of AMD and provide some relief from eye symptoms. There is also some evidence that eating a balanced diet filled with fresh fruit and vegetables will help give your eyes nutrients that can boost eye health.
Wet AMD:
According to the RNIB The treatment available on the NHS for wet AMD is a group of anti-vascular endothelial growth factor (anti-VEGF) drugs. As new blood vessels form in your eye, your body produces a chemical which encourages further new blood vessel growth. Anti-VEGF drugs interfere with this chemical and stop the vessels from growing, minimising further damage to your sight. The medication is injected into the vitreous, a gel-like substance inside your eye. This is called an intravitreal injection. This injection must be given in an operating theatre or a “clean room” to avoid infection. A clean room is a sterile room which may not have the full facilities of an operating theatre.
Before the injection, you will be given anesthetic eye drops to make your eye numb and an antibiotic drop to help prevent you from getting an infection. The injection shouldn’t be painful thanks to the anesthetic, but your vision may be a little sore after the anesthetic wears off. There is a slight chance that the pressure inside your 25 eyes may rise slightly, but it shouldn’t cause pain or change your vision. The sight in your treated eye may be blurry because of the treatment, but this should wear off within a day. You may notice a small black circle in the lower part of your vision. This is caused by a small air bubble which will disappear after a few hours. You may also have slight swirls in your vision for a few days following the injection, but this doesn’t always happen to everyone. Your eye may water a bit more after the injection and may be slightly red or irritating. This usually gets better after 26 a few days. If your eye becomes very painful or red and hot to the touch, or if you notice any worsening of your vision, you should let your hospital know as soon as possible. The main complications of this treatment are the chance of a rise in pressure in your eye, retinal detachment (where the retina at the back of the eye peels away from its normal position) and eye infections. These complications are rare, happening to less than one percent of people having the injections. There are treatments available if any of these complications occur to you.
Coping with Age-Related Macular Degeneration
Age-related macular degeneration can result in severe loss of central vision but rarely causes blindness. It can, however, make it difficult to read, drive or perform other daily activities that require fine central vision. In AMD, the health of the peripheral retina is unaffected, so patients can rest assured that their peripheral (side) vision and ability to walk around without bumping into things are usually preserved.