Age-related macular degeneration (AMD)
Age-related macular degeneration (AMD) is a degenerative disease of the retina that affects the fovea. It is linked to the aging of the retinal tissues. AMD is the leading cause of visual impairment in older adults in France. The first symptoms are decreased vision and distorted vision (metamorphopsia). Unlike glaucoma, for example, AMD never leads to complete blindness (total blackness), but the loss of central vision (central scotoma) can be very debilitating and prevent reading and driving. In advanced stages of the disease, mobility remains possible. Several risk factors exist, including age, smoking, a diet high in fat, being female, and genetic predisposition (a family history of AMD). The role of blue light is a subject of debate.
What is AMD?
Age-related macular degeneration is a degeneration of the retina, specifically in its central part, the macula, which is responsible for detailed vision.
What is the macula?
The functioning of the eye can be compared to a camera, with the pupil being likened to the diaphragm of the lens, the cavity of the eye (vitreous cavity) to a dark chamber, and the retina to the photographic film.
The macula is an area of approximately 5mm, which corresponds to the central part of the retina onto which light rays are projected.
It contains the most sensitive photoreceptors (cones), which allow precise vision (visual acuity) thanks to which it is possible to read small print or recognize facial features.
Central vision, as opposed to peripheral vision, allows for coarser vision but ensures visual field. The latter is never lost during age-related macular degeneration (AMD).
Age-related macular degeneration (AMD)
In its early stages, AMD is asymptomatic. It is called "age-related maculopathy" – AMD.
Only an ophthalmologist can uncover the first signs at this stage in the fundus of the eye, or with OCT by visualizing "drusen".
Simple monitoring and sometimes vitamin supplementation are recommended.
Age-related macular degeneration
Age-related macular degeneration occurs when photoreceptors in the retina are damaged and die.
This degeneration can lead to areas of atrophy (necrosis) of the macula or to abnormal reactions with the formation of a new blood vessel.
The different types of AMD
There are two forms of AMD that can coexist. They are distinguished by their rate of progression and the presence or absence of edema.
Atrophic AMD, also known as "dry AMD"
It is the most common (approximately 80%) and evolves very slowly over several years, or even decades.
Visual cells are gradually lost. This involves atrophy of the retinal tissue and the deep layers of the retina, accompanied by the disappearance of light receptors.
Exudative AMD, also known as "wet AMD"
It can follow a dry form or be an early sign of the disease.
It corresponds to the appearance of chaotic blood vessels (neovascularization) in the retinal tissue, responsible for edema and a rapid decline in vision.
This form is more aggressive than dry AMD, but benefits from a treatment: intravitreal injections.
The symptoms
The three main symptoms of AMD are as follows:
A decrease in visual acuity – Vision is blurry even though the optical correction is appropriate.
A central scotoma – Loss of central vision (the area in the center of vision). As the condition progresses, certain activities such as reading or recognizing faces become difficult, but movement is still possible because peripheral vision remains intact.
Metamorphopsias – Undulations of straight lines, which can be objectified by the Amsler grid test.
What is the vision like with AMD?
In the case of age-related macular degeneration (AMD), your vision will gradually deteriorate. There is no miracle cure, no retinal transplant, no cell transplant, and no bionic eye.
Your central vision will gradually and very slowly deteriorate, accompanied by a scotoma (black spot), metamorphopsia (distorted lines), and a sensation of blurriness. Your peripheral vision will remain intact.
Only regular monitoring and, if necessary, treatment can maintain vision. It is therefore essential to have complete trust in your ophthalmologist, who will provide the necessary follow-up care and administer injections when needed. A delay in treatment often has serious consequences.
Progression and complications of AMD
The main risk of AMD is the progression towards a loss of central visual acuity. Blindness is not total, but the central scotoma can be extremely debilitating.
It is the leading cause of vision loss in industrialized countries. Certain complications can also arise during the progression of age-related macular degeneration (AMD).
Neovascularization – This is the wet form of the disease, which requires intravitreal injections of anti-VEGF to inhibit the growth of uncontrolled blood vessels.
Macular hematoma – This complicates neovascularization and causes a very sudden loss of visual acuity. Urgent vitrectomy surgery, accompanied by a subretinal injection of rt-PA, is essential.
Vitreous hemorrhages – Although less common, vitreous hemorrhages are also possible. They require intravitreal injections, as with any wet form of the condition.
The different exams
The examination at the ophthalmologist's office will include a visual acuity measurement, dilation to perform a fundus examination, and a macular OCT.
Fundus examination – Fundus examination is a simple test that allows observation of the retina and blood vessels. The ophthalmologist uses a light directed through the pupil and a convex examination lens.
Macular OCT – Optical Coherence Tomography is a type of non-irradiating retinal scan that uses optical principles. It provides excellent visualization of the macula and is a key examination in ophthalmological monitoring for detecting the presence of any new blood vessels very early. It is repeated at each consultation.
Retinal angiography – Previously, it was the gold standard examination. OCT, which provides a very precise image, and OCT angiography are tending to replace it. In some cases, however, it remains essential. After intravenous injection of contrast agents (fluorescein +/- indocyanine green – ICG), it allows for perfect visualization of the retinal vasculature and is a valuable diagnostic tool.
Treatments for AMD
If you have any doubts – consult an emergency doctor immediately!
The most important point concerns this. At the slightest doubt, at the appearance of the slightest deformity (metamorphopsia), it is essential to consult a doctor urgently.
A fundus examination and OCT scan will confirm or rule out the diagnosis. Wet forms require treatment within a few days; otherwise, the damage is irreversible.
Dry AMD – The importance of self-monitoring
There is no truly effective treatment for dry AMD.
Dietary supplements (vitamins, antioxidants and zinc) can be taken as a preventative measure.
However, regular monitoring by an ophthalmologist is recommended.
Furthermore, self-monitoring is essential. You can print an Amsler grid and, on a weekly basis, alternately close one eye and then the other, test each eye. If you suspect metamorphopsia, consult a doctor immediately.
Pegcatacoplan: a treatment of the future?
Research and innovation are extremely active in the field of age-related macular degeneration (AMD). Pegcetacoplan, a complement inhibitor, has been approved since February 2023 for the treatment of geographic atrophy (an aggressive form of atrophic AMD). Its authorization in Europe is expected in early 2024.
Wet AMD – Intravitreal injections
The exudative (or wet) form progresses very rapidly without treatment. "Anti-VEGF" drugs (Lucentis ranibizumab – Eyla Aflibercept) inhibit the growth of new blood vessels.
They require intravitreal injection to be effective.
They are administered monthly for three months, then the frequency of injection depends on the progression of the disease.
Intravitreal injections are performed under local anesthesia (more information here) .
They will be repeated for months or even years.
Hematoma treatment – Vitrectomy and rt-PA
Macular hematomas are treated by injection of rt-PA (actilyse) following a vitrectomy.
Vitreous hemorrhages, on the other hand, require treatment by injection alone.
Low vision rehabilitation to support those with chronic, irreversible visual acuity loss
In the event of residual discomfort not amenable to treatment or profound vision loss, your ophthalmologist may refer you to professionals specializing in low vision.
The optician will offer you optical equipment such as magnifying glasses or advise you on optimal lighting. The orthoptist, on the other hand, can offer you rehabilitation to help you optimize your residual vision.
Frequently Asked Questions
Does AMD cause blindness?
No! AMD does not cause blindness, but it does cause visual impairment. Central vision can be severely affected. However, peripheral vision will remain intact.
How to stop the progression of AMD?
AMD is a degenerative disease. Therefore, there is no way to stop it, only solutions to slow it down.
Sun protection
A balanced, varied diet, rich in Omega 3
Vitamin supplementation may be necessary.
Regular ophthalmological checkups
Treatment by intravitreal injections in the case of the wet form
Can AMD be cured?
Yes! AMD can be treated but not cured.
Dry AMD requires appropriate sun protection, a balanced diet and, if necessary, dietary supplements.
Wet AMD requires repeated injections to treat the toxic edema of the retina.