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Basics of age-related macular degeneration

Updated: Nov 11, 2024


How to Check Vision Using the Amsler Chart

Check using the chart for checking

How to check

(1) Move about 30 cm away from the patient (with glasses still on).


(2) Always check one eye at a time


(3) Close one eye and gaze at the black dot in the center of the chart.


Understanding Age-Related Macular Degeneration (AMD)

It can be said that the treatment of age-related macular degeneration has changed dramatically over the past 10 years. In this context, treatment using VEGF inhibitors has played an extremely important role, and it has become possible to save the visual function of many patients who previously went blind. However, it remains a major cause of premature blindness, and its prevalence is increasing year by year.

What is age-related macular degeneration?

As people age, the macula, the central part of the retina, is damaged, leading to decreased visual acuity, and is the fourth leading cause of visual impairment in Japan.

Age-related macular degeneration is classified into two types: wet type and atrophic type. In the exudative type, new blood vessels occur in the choroid, and leakage or bleeding from the new blood vessels affects the visual function of the macula. In the atrophic type, the function of the macula decreases due to atrophy of retinal pigment epithelial cells. More than 90% of age-related macular degeneration in Japanese people is of the wet type.

The prevalence of wet age-related macular degeneration in towns has been shown to be increasing year by year, from 0.6% in 1998 to 1.2% in 2007 and 1.5% in 2012. The reason for this is that the elderly population is increasing as the population ages. Furthermore, there is a large difference in the prevalence of age-related macular degeneration between men and women, with men having a prevalence of more than four times higher than women (2012).


Subjective symptoms of age-related macular degeneration

Symptoms of age-related macular degeneration include metamorphopia, where the center of objects is distorted, scotoma, where part of the visual field is missing, and central scotoma, where the center appears dark, and as the condition progresses, vision deteriorates. Masu.


Characteristics of visual impairment due to age-related macular degeneration

Visual impairment caused by age-related macular degeneration is characterized by a decline in central vision because the center of the visual field, that is, the part you want to see most, appears distorted or dark, but you can still see the peripheral areas. Therefore, although I can walk normally, I can't see the center of my field of vision, so for example, even if I meet someone on the street, I can't see their face, and when I try to read a newspaper, I have difficulty reading the part of the text I want to read. It is. However, since you can see the surrounding area, you can notice, for example, trash falling indoors. However, if it progresses without treatment, peripheral areas may become invisible.

On the other hand, in the case of glaucoma, which is the number one cause of visual impairment, visual field is lost from the periphery, and central visual field and central vision are maintained until the terminal stage. The methods are very different.


Mechanism of age-related macular degeneration

In normal retinal tissue, retinal pigment epithelial cells located under the retina have the ability to phagocytose waste products from photoreceptor cells. As this function becomes impaired with age, unphagocytosed waste products thicken under the retinal pigment epithelium.

If the retinal pigment epithelium is damaged, choroidal neovascularization will grow from the choroid, which is rich in blood vessels, toward the retina. New blood vessels are extremely weak and abnormal, so they can easily rupture. Hemorrhage and serous fluid leakage cause macular edema, serous retinal detachment, and retinal pigment epithelial detachment, which destroys the retinal pigment epithelium and photoreceptor cells, leading to vision loss.


What causes age-related macular degeneration?

Research into the cause of age-related macular degeneration is progressing all over the world, but it is still not clear. What we currently know is that age-related yellowing is a disease associated with dominant inflammation and is related to oxidative stress, and that oxidative stress affects retinal pigment epithelial cells, retinal photoreceptors, and choriocapillary plate. Although it is said to be caused by injury, there is currently no unified opinion on the factors that trigger the onset of the disease.

The only common risk factor cited in many studies is smoking, with smokers having four times the risk of developing age-related macular degeneration than non-smokers. The prevalence rate is higher in Japanese men than in women, which may be due to the fact that in the past, Japanese men were overwhelmingly more likely to smoke, while women were less likely to smoke. It is said. However, in addition to smoking, other risk factors include race, gender, genetic factors, high blood pressure and cardiovascular disease, and active oxygen increases oxidative stress in the body. Risk factors include exposure to blue light and stress.


Basic concept of treatment

Regarding treatment, if the lesion is active, that is, if new blood vessels are confirmed, treatment is performed, but if the lesion is inactive, such as a precursor lesion, no treatment is given, and if a transition to the exudative type is observed. We will carefully monitor the progress.


On the other hand, there is currently no treatment for the reduced type, and there is no effective treatment for advanced scar lesions in the exudative type, and there is no hope for improvement, so we will have to wait and see.


If wet age-related macular degeneration goes untreated, it generally worsens over time, although there are individual differences, so treatment should be performed as soon as new blood vessels appear. However, the goal of current treatments is to preserve visual function. If treatment is effective, there may be some improvement, but it will not return to normal. In other words, even if treatment is started after visual function has significantly deteriorated, it is only possible to maintain the visual function at that point, so it is important to find out how to detect it early, treat it early, and maintain visual function. is very important.


Types of treatment

There are three treatment methods for wet age-related macular degeneration:

〇Anti-VEGF therapy

A vascular endothelial growth factor (VEGF) inhibitor is injected into the vitreous from a position 4 mm behind the cornea (the iris of the eye) to inhibit VEGF in the focal area, resulting in new growth. This treatment does not completely eliminate new blood vessels, but rather puts a brake on the progress of new blood vessels, so even if this treatment is performed, new blood vessels will not completely disappear. Recurrence may occur. Therefore, even after a certain period of treatment, it is necessary to continue treatment as a maintenance phase while monitoring the activity of the lesion.

〇Photodynamic therapy (PDT)

Photodynamic therapy (PDT) involves intravenously injecting the photosensitizing substance verteporfin (Visdyne) and irradiating the lesion with low-power laser light, causing a chemical reaction with the drug that reaches new blood vessels. This is a treatment method that causes regression of new blood vessels. Since the retina is not cauterized, it can be treated even if the lesion is located in the center. Because photosensitivity may occur, it is necessary to physically block light for 48 hours after treatment by wearing a hat, sunglasses, a mask, long sleeves, long pants, gloves, etc.

〇lazer solidification method

This treatment uses laser light to cauterize new blood vessels, including those in the retina. Since the normal retina is also cauterized, the visual field at the irradiated area is lost, so this treatment is only possible if there are no new blood vessels in the fovea.


Treatment selection and concept

The treatment guidelines of the Japanese Society for Medical Sciences (2012) indicate that if choroidal neovascularization is not located in the center, laser coagulation should be performed, and if choroidal neovascularization is located in the center, PDT or anti-VEGF therapy should be performed. Masu.


However, the reality is that in many cases the new blood vessels are located near the center, so laser coagulation is not often used at present. In addition, there are a certain number of cases where PDT causes bleeding and sudden loss of vision after the procedure, so it is difficult for people with good eyesight to perform it, so it is no longer performed very often.


Against this background, anti-VEGF therapy has essentially become the current standard treatment for wet age-related macular degeneration.


However, when anti-VEGF drugs are administered to a child, a very small amount passes into the bloodstream, decreasing the blood VEGF concentration, thereby increasing the risk of arterial thromboembolism such as cerebral infarction. Therefore, in patients with a history of cerebral infarction, the frequency of anti-VEGF therapy is reduced and a treatment format that also includes PDT is used. It has been found that the frequency of bleeding, which is a problem with PDT, can be reduced by using it in combination with anti-VEGF therapy, and the effect of reducing the number of anti-VEGF therapy treatments has been confirmed.


Supplement positioning

Another effective treatment is supplements. The Age Related Eye Disease Study (AREDS) study, a large-scale trial conducted in the United States23, provided evidence of the effectiveness of supplement intake in suppressing new blood vessels. It is highly recommended to take AREDS-prescribed supplements. Supplements containing lutein* are sold based on the AREDS prescription. Supplements are strongly recommended for the atrophic type, for which there is no treatment, and during the follow-up phase for precursor lesions.


*Lutein: Lutein is a yellowish pigment found in foods such as spinach and corn, and is called macular pigment because it is abundant in the macula. Lutein has a strong antioxidant effect, which protects the macula from oxidative stress, and by absorbing blue light, it also protects the macula from photooxidative damage, but its amount decreases with age. Since it cannot be synthesized in the human body, it is important to ingest it through food or supplements.

Don't do anything because it's hard to see

People with age-related macular degeneration have visual problems in which they cannot see the central part of their eyes. However, the term visually impaired generally has the image of ``not being able to see at all,'' and people do not understand that it means not being able to see at all.

This is the stress that patients with age-related macular degeneration feel.

For example, when you try to pay your fare on a bus, you can't see what you're paying for, or when you try to look at the fare list at a ticket vending machine at the station when you're about to board a train, you can't see the part you want to see. Therefore, I have to ask the people around me every time.

Being unable to do something without someone's help can be very stressful for patients. Because of this, it is said that patients with age-related macular degeneration are more likely to become withdrawn. However, in the elderly, this directly leads to cognitive decline and frailty.

If you have an IC card, you can ride trains and buses freely without having to ask people about the fare, so I encourage people to go out more often.


How to use tools to see things

Nowadays, various magnifying glasses are sold in shops. I would like you to buy various types of magnifying glasses and use the one that is easy for you to see.Tablet devices like the iPad are also very useful, and you can take pictures of what you want to see at your fingertips. You can enlarge the image to a size that is easy for you to view, which is very convenient for people with visual impairments. It is very important to take steps and train yourself to see on your own before your eyesight deteriorates.

If you still have trouble seeing even after trying your best, you can receive low vision care. In low vision care, we use various aids to find out what magnification is needed to achieve reading speed, using reading speed as a guideline to determine how fast a patient can read text. We will suggest the available aids.

If you still get tired of watching even after trying these methods, there are now audio options available such as Audible. It is very important to utilize various tools to input information and continue to stimulate the brain.


What you can do for prevention

Things that people over the age of 50 can do to prevent the onset of age-related macular degeneration include smoking cessation, taking supplements containing lutein, and eating green and yellow vegetables, but they also need to be careful about sunlight, specifically UV rays and blue rays. It's about protecting your eyes from the light.

Blue light is said to be bad for your eyes because it is emitted by smartphones and PCs, but in fact blue light is also emitted from sunlight, so sunglasses that can block not only UV rays but also blue light (Ultra Guard/Tokai) It is useful to wear a pair of glasses (manufactured by Kogakusha, etc.).


Regularly check your vision with one eye

We perceive objects visually by transmitting information seen with both eyes to the brain. Even if there is an abnormality in the way you see or what you cannot see with one eye, by supplementing the information from the other eye, you will be able to see without feeling any discomfort. Therefore, even if symptoms such as metamorphosis and central scotoma appear in one eye due to age-related macular degeneration, which often starts in one eye, the abnormality may not be noticed, and by the time it is felt, it has progressed. This is often the case.

For this reason, it is extremely important to regularly check your vision with one eye. For this purpose, the Amsler chart is extremely useful as it allows you to easily check symptoms. You can also download it from the Internet (https://www.healthcare.novartis.co.jp/moumaku/selfcheck) and print it out, so even insurance pharmacies can display it in the waiting area or print out the Amsler chart along with drug explanations. If we could carry out awareness-raising activities to encourage patients to regularly check their vision by themselves, such as by handing them out, I think it would be a great help for early detection and early treatment.


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