Age-related macular degeneration (AMD, formerly known as age-related macular degeneration) can be divided into early, intermediate, and progressive stages, with progressive AMD causing irreversible central damage in people over 50 years of age in the Western world. The prevalence of early and progressive AMD increases with age: Western statistics show that AMD affects 14.4% of people aged 55–64 years, 19.4% of people aged 65–74 years, and 36.8% of people aged 75 years or older. As the average age of the population in the Western world increases, so does the incidence of AMD. Domestic statistics: 50-59 years old, 5.7%, 60-69 years old, 13.5%, 70-79 years old, 20.2%, >80 years old, 23.5%, with the aging of China’s population, the incidence of AMD is also on the rise. visual acuity in patients with AMD: blindness (daily life visual acuity < 0.05) 5.1%, low vision (daily life visual acuity > 0.05 but < 0.3) 31.3%. 31.3%. Progressive AMD can be divided into two types: non-neovascular (including map-like atrophy of the retinal pigment epithelium in the center of the macula) and neovascular CNV). 80-90% of severe vision loss in AMD is due to neovascularization. Due to the increasing incidence of neovascular AMD and the threat to vision, it is important to inform the public about AMD and the benefits of its treatment. The structure of the eye can be simply compared to a camera (Figure 1). The retina is the equivalent of the film, which is light-sensitive. The macula is a special structure with a diameter of about 2mm located in the center of the posterior pole of the retina, which is the most sensitive and critical part of human vision. Its functions include: fine vision, color vision recognition, including our daily watching TV, reading and reading newspapers. Once the macula is damaged, vision will be severely damaged. Figure 1:The eye and the camera II. About age-related macular degeneration (AMD) Age-related macular degeneration (AMD) refers to the development of vitreous warts, map-like atrophy, and/combined with choroidal neovascularization in the macula of people over the age of 50 and the hemorrhage, oozing, edema, neuroepithelial detachment, pigment epithelial detachment it causes, etc. The pathogenesis of AMD is still not clear, and the rate of public awareness is very low (2%), and the effective treatment for AMD is very limited. There are very limited effective treatments for AMD, and it is recognized as one of the most difficult eye diseases to treat in ophthalmology. Risk factors associated with AMD include: 1. age: significant age correlation, with a high risk above 50 years of age; 2. gender: women are twice as likely as men; 3. ethnicity: Caucasians are more likely to suffer from CNV AMD than blacks and browns; 4. high blood pressure and heart disease; 5. family history; and 6. light pigmentation, overly transparent crystals, and a tendency to have a darker, more transparent iris than a darker, more brown iris. light pigmentation, excessively clear crystals, aphakia, and hyperopia; 7. smoking; 8. regular exposure to blue light and bright light; and 9. nutrition, such as carotene deficiency. Figure 2:Dry AMD: posterior pole vitreous warts AMD is the leading cause of blindness in Western populations over 50 years of age, severely damaging central vision, and the risk of developing the disease increases significantly with age, affecting approximately 2.5 million people in developed countries.AMD can be classified as dry AMD (80%, Figure 2) and wet AMD (20%, Figure 3), with dry AMD visible as vitreous warts on the fundus. Wet AMD: characterized by the formation of choroidal neovascularization Figure 3: Wet AMD: CNV causes macular hemorrhage and edema (CNV), which is the most harmful, often causing hemorrhage, exudation, edema, neuroepithelial detachment, pigment epithelial detachment, etc. If not treated in time, it will lead to severe vision loss, loss of central vision or blindness, and will be in the range of 3 to 5 years. The main symptoms of AMD include: decreased visual acuity, dark spots in the center of the visual field, decreased visual contrast, distorted vision, difficulty in performing normal visual tasks such as reading, telling time, recognizing faces, driving, and other daily living functions, requiring the assistance of family members and caregivers, and the inability to work and fulfill occupational aspirations. The quality of life is seriously affected. Since the cause and pathogenesis of AMD are still unclear, prevention is very difficult. However, recent studies have shown that the active metabolism and high oxygen consumption of the retina, which is often exposed to visible light and prone to oxidative damage, may be the cause of AMD. Therefore, more and more scholars believe that antioxidants can stop free radicals from damaging cells, which may be of some significance in the prevention of AMD, and recommend appropriate supplementation of lutein, zinc, vitamin C, vitamin E, carotenoids and so on. Numerous studies have shown that taking antioxidants has a protective effect on the retina and can reduce the conversion of dry AMD to wet. For the treatment of wet AMD, neovascularization is primarily targeted. For neovascular AMD located outside of the macular central pucker, treatment is relatively simple and can be achieved by directly sealing the neovascularization with laser photocoagulation. Unfortunately most neovascular AMD occurs in the central or paracentral macula and cannot be treated with direct photocoagulation because photocoagulation destroys the retina and impairs central vision. For neovascular AMD located in the subcentral concavity or paracentral center, the most effective method that preserves useful vision is photodynamic therapy (PDT): i.e., intravitreal injection of highly selective Visudyne photosensitizer liposomes (7 ml of water for injection to make 7.5 ml, calculate the dose to be given according to the body surface area of 6 mg/m² dilute and make up to a 30 ml of solution and infused at 3 ml/min over 10 minutes). Fifteen minutes after starting the injection, the drug in the eye was activated with a non-thermal laser of 689 nm wavelength, which led to an energy jump through photochemical reaction, generating singlet oxygen and oxygen radicals, destroying the endothelial cells of the neovasculature and further occluding the choroidal neovasculature without affecting the normal tissues around it. In contrast, before the advent of Visudyne therapy, laser coagulation used a high-energy thermal laser to directly irradiate the fundus and destroy CNVs without selectivity, instantly damaging normal retinal tissue. PDT has been carried out in the West for 8 years, and a small number of clinical trials began in China in 2000, and it has only been 3 years since it was actually approved by the state for clinical treatment. Many doctors who are not specialized in retina do not understand PDT, let alone patients. Studies at home and abroad have shown that PDT treatment can stabilize the vision of more than half of wet AMD patients and greatly improve the quality of life of patients.After PDT treatment, patients need to pay attention to avoiding photosensitivity: within 48 hours, they should pay attention to avoiding exposure to strong light, such as strong sunlight, especially bright lobby, halogen light at home and office, stomatology and surgical light source, etc.; the treatment is arranged in the afternoon as much as possible. Patients should wear and bring the following items to the hospital on the day of treatment: wide-brimmed hat, long-sleeved top and pants, dark-colored sunglasses, gloves, etc.; wearing sunglasses can be used to watch TV and movies, and should not stay in the dark room all the time, because proper exposure to indoor light will help inactivate the photosensitizers in the skin. 7 years of more than 2 million people around the world for the PDT treatment confirms its effectiveness and good safety for wet age-related macular degeneration. and a favorable safety profile. Of course, any treatment may have adverse effects, and the adverse effects of PDT include: skin reactions at the injection site, infusion-related back pain, temporary blurring of vision or visual deficits, and severe vision loss (significant loss of vision within 1 week of treatment in about 1%-4% of cases, with most recovering after 1 week). Numerous publications have reported that the incidence of the above adverse reactions is very low and mild, mainly in the early stages of PDT development, and is now relatively rare. It should be noted that although PDT treatment is very effective and has few side effects, it still treats the symptoms, not the cause, and there is currently no cure for AMD. Therefore, there is still a possibility of AMD recurrence after PDT treatment, and once recurrence occurs, PDT treatment is needed again. Therefore, it is necessary for the patient to cooperate with close follow-up observation after treatment, and it is required to have a review one week, one month, and every three months thereafter. The review items include: visual acuity, fundus examination, fluorescence angiography (FFA &ICG), optical tomography (OCT), etc., in order to evaluate the efficacy of the treatment and to determine whether to have another treatment or not. In addition, if the lesion is large, the history of the disease is long, and the vision is very poor before receiving treatment, then even if the vision can be stabilized, it will be stabilized at a lower level of vision. Therefore, we suggest that patients with indications for PDT should be treated as early as possible. Studies have shown that patients with small lesions, a short history of disease, and good visual acuity can maintain good visual acuity and their quality of life will not be affected by the treatment. This requires vigilance on the part of the patient and the ophthalmologist. Patients with decreased vision, distorted vision, and dark shadows should be examined by an ophthalmologist as soon as possible; the ophthalmologist, based on the patient's complaints, may first perform a visual acuity examination, Amsler's form examination (Fig. 4), and fundoscopy, and find that the grid is blurred, distorted, or has an abnormal color, and that further investigations are necessary: fluorescence angiography (FFA & ICGA), OCT, etc. If neovascular AMD is identified, referral to a retinal specialist is made as soon as possible so that PDT can be performed as soon as possible to preserve useful vision. Finally, in order to completely close the choroidal neovascularization, reduce the chance of AMD recurrence and reduce the number of PDT treatments, foreign countries have carried out combination therapy. That is, PDT combined with intravitreal injection of anti-neovascularization drugs can improve the efficacy and visual acuity of patients. However, it is still quite some time before these drugs are approved for use in China, and PDT will remain the most effective treatment for wet AMD in the next few years.