Age-related macular degeneration(from uptodate)
流行病學
AMD 是西方世界成年人嚴重中央視力喪失和失明的最常見原因 [11]。據估計，全球 AMD 盛行率約為 8% 至 9%，影響約 1.9 億人（美國為 1,800 萬）[12-15]。據預測，到 2040 年，全球將有近 2.5 億人受到這種疾病的影響[12]。發病率和盛行率隨著年齡的增長而增加。2004 年美國人口的一項研究顯示，整體盛行率為 1.5%，80 歲以上族群的盛行率增加了十倍（15%）[16,17]。一項針對歐洲患者的研究表明，早期 AMD 的盛行率從 55 至 59 歲人群中的 3.5% 增加到 85 歲以上人群中的 17% 以上 [18]。
EPIDEMIOLOGY
AMD is the most common cause of severe central vision loss and legal blindness among adults in the Western world [11]. The estimated worldwide prevalence of AMD is approximately 8 to 9 percent, affecting approximately 190 million people (18 million in the United States) [12-15]. It is predicted that worldwide, almost a quarter billion people will be affected by this disease by 2040 [12]. The incidence and prevalence increase with age. A study from 2004 of the United States population showed an overall prevalence of 1.5 percent that increases by tenfold (15 percent) for those over the age of 80 [16,17]. A study among European patients showed prevalence of early AMD increasing from 3.5 percent among people aged 55 to 59 to over 17 percent for those over the age of 85 [18].
發病機轉
AMD 的發病機制仍知之甚少。它顯然是一種多因子、多基因疾病[1,2,19-23]。老化仍是最重要的單一風險因子[24-26]。全基因組定序已識別出一組52 個常見變異，映射到34 個基因座，其中最顯著的變化發生在1 號染色體（補體因子H 基因座）[27-31] 和10 號染色體（ARMS2/ HTRA1 基因座）[19]。已確定參與AMD 發病機制的其他因素包括脂質穩態失調[4,32]、自噬受損[33-36]、氧化壓力增加[37,38]、發炎/副發炎[39-41] 、局部鐵超載/鐵死亡[42]，以及有毒玻璃膜疣相關物質的累積[43-46]。
PATHOGENESIS
The pathogenesis of AMD remains poorly understood. It is clearly a multifactorial, polygenic disease [1,2,19-23]. Aging remains the single most important risk factor [24-26]. Whole-genome sequencing has identified a set of 52 common variants mapped to 34 loci, with most notable changes in chromosome 1 (complement factor H locus) [27-31] and chromosome 10 (ARMS2/HTRA1 locus) [19]. Other factors identified to be involved in AMD pathogenesis include lipid dyshomeostasis [4,32], impaired autophagy [33-36], increased oxidative stress [37,38], inflammation/para-inflammation [39-41], local iron overload/ferroptosis [42], and accumulation of toxic drusen-associated materials [43-46].
危險因子
重要的不可改變的危險因子包括年齡較大和遺傳風險，而可改變的危險因子包括吸菸和飲食類型（飲食中抗氧化劑攝取量低）[47,48]。流行病學研究表明，目前吸菸者罹患 AMD 的可能性是不吸菸者的兩倍，而戒菸者的風險明顯較低，且 20 年前戒菸的人風險並沒有增加 [49]。包含水果、蔬菜和魚類的地中海飲食可降低 AMD 風險[50-57]。
RISK FACTORS
Important nonmodifiable risk factors include older age and genetic risk, while modifiable risk factors include smoking and type of diet (low dietary intake of antioxidants) [47,48]. Epidemiologic studies have shown that current smokers are twice as likely to have AMD compared with nonsmokers, whereas ex-smokers had significantly less risk and people who quit smoking >20 years previously were not at increased risk [49]. A Mediterranean diet that includes fruits, vegetables, and fish is associated with a lower risk of AMD [50-57].
關於血壓和 AMD 之間關係的數據不牢固或不可重複 [58,59]。同樣，血脂升高或其他心血管危險因子與 AMD 之間的關係仍有爭議 [60]。
The data on the relationship between blood pressure and AMD are not strong or reproducible [58,59]. Similarly, the relationship between elevated lipid or other cardiovascular risk factors and AMD remains controversial [60].
AMD
在早期可能無症狀。患者往往會出現對比敏感度和對黑暗環境的適應問題。他們可能會抱怨自己需要更明亮的燈光和更多的時間來閱讀，並且在下雨天或陰天等低對比度的情況下，他們的視覺功能會更差。在明亮的日子裡，當他們從明亮的環境進入黑暗的環境時（即，當駕駛並進入隧道時）或當他們從明亮的房間進入黑暗的房間時，他們也會受到影響。最終，隨著疾病的進展，他們的中心視力下降，他們不僅在閱讀方面遇到困難，而且在識別他人的臉和臉部表情方面也遇到困難。幾乎所有患者的周邊視覺功能都與未受影響的個體非常相似。有些患者可能還會注意到直邊的扭曲，例如門或百葉窗。這種後期症狀的突然發作需要在幾天到一周內進行緊急檢查，因為它可能預示著進展為晚期濕型。
據估計，大約 15% 的患者將失明（中心視力低於 20/200），但完全失明並不是這種疾病的典型結果。這種疾病影響雙眼，但可能是不對稱的。如果一隻眼睛轉變為疾病晚期，另一隻眼睛有 50% 的機會在五年內進展到該階段 [8,9]。
CLINICAL PRESENTATION
AMD may be asymptomatic in early stages. Patients tend to present with problems in contrast sensitivity and adaptation to dark environments. They may complain that they need brighter lighting and more time to read and that their visual function is worse in situations with low contrast like rainy or overcast days. They will also be affected on bright days when they go from a bright to a dark environment (ie, when driving and entering a tunnel) or when they go from a brightly lit room to a darkened one. Eventually, as the disease progresses, their central visual acuity declines and they have trouble not only in reading but in recognizing faces and facial expressions of other people. In almost all patients, the peripheral visual function will remain very similar to that of unaffected individuals. Some patients may also notice distortion of straight edges such as doors or window blinds. Sudden onset of this later symptom requires urgent examination within few days to a week since it could herald progression to the advanced wet form.
It is estimated that approximately 15 percent of patients will become legally blind (central visual acuity less than 20/200), but complete blindness is not a typical outcome of this disease. The disease affects both eyes, but it can be asymmetric. If one eye converts to the advanced stage of the disease, the other eye has a 50 percent chance of advancing to that stage within five years [8,9].
