高度近視是導致不同眼疾的風險因素

高度近視一般定義為近視度數達六百度或以上。有研究統計出在亞洲地區青年人患有高度近視的比率為6.8% – 21.6%,1 當中人口稠密的大城市有高度近視的比率遠比偏遠的郊區為高,相信從這些數字估算出香港有高度近視人口比率絕不少於15%。高度近視患者視力一般能透過配帶近視鏡片矯正過來,但高度近視或會導致某些眼疾,令患者的視力不能原全矯正過來,本篇網誌便會探討一下高度近視與不同眼疾的關係。

病理性近視

高近視患者的眼球長度比沒有近視的長很多,就是因為眼球被拉得過長的緣故,導致視膜網黃班區和視膜網背後的脈絡膜出現病理性變化。新加坡近年有研究指出大概每100患有高近視的青年就有8名出現病理性近視的情況,2 由此可見,病理性近視的發生率絕不低。病理性近視被歸類為5種臨床表徵,當中“黃斑部脈絡膜新增血管病變”就是其一種較快令到視力永久受損的情況,如發現視網出現新增血管或滲血,眼科視光師便會立刻轉介病人到眼科醫生處為眼球進行 “眼內注射血管內皮生長素抑制劑”,從而希望減低其對視力帶來的永久損害及為視力帶來某情度的恢復。而高近視患者亦應多加注意,每年進行定期眼睛檢查,如發現視力突然變差或直線變曲,便應盡快進行全面眼睛檢查。

視網膜脫落

由於高近視患者視網膜前的玻璃體比起沒有度數的正常眼睛較早出現退化和液化,導致視網膜較易出現裂痕甚至脫落。有研究曾指出高近視的眼睛較沒有近視度數的眼睛出現視網膜脫落的風險高達20倍,4 所以高近視患者如出現飛蚊和閃光的視網膜脫落症狀,就應立刻進行放瞳眼底檢查,查明完因。

青光眼

眼球過長除了令黃班區較易出現病理性變化外,亦有可能因此而拉扯到視神經,導致較大機會出現青光眼。近年一個從北京進行的研究指出,在同等的眼壓下,高近視患的眼睛比沒有近視度數的眼睛出現青光眼的風險高約7.5倍。5 早期的青光眼是沒有明顯的病徵,患者必需透過眼底檢查才能知悉是否患有青光眼。

白內障

高近視患者是否較大機會患有白內障於現階段還未有確切的答案,一些研究找到有關聯性,一些沒有。6 不過,有一點值得一題就是高近視患者完成白內障後較一般人口較大機會出現視網膜脫落的併發症(高近視的發生率為2.2%,而一般人口的發生率為0.93%)。7, 8

註冊眼科視光師(第一部份) 陳家豪


以上護眼資訊由瑞士寶視光中心提供

地址 : 香港新界荃灣海盛路11號 One Midtown 23樓全層

查詢/預約電話 : +852 2751 8491

綢址: www.swisscoat.com.hk


參考文獻:

  1. Wong YL, Saw SM. Epidemiology of Pathologic Myopia in Asia and Worldwide. Asia-Pacific journal of ophthalmology (Philadelphia, Pa) 2016; 5(6): 394-402.
  2. Koh V, Tan C, Tan PT, et al. Myopic Maculopathy and Optic Disc Changes in Highly Myopic Young Asian Eyes and Impact on Visual Acuity. American journal of ophthalmology 2016; 164: 69-79.
  3. Akiba J. Prevalence of posterior vitreous detachment in high myopia. Ophthalmology 1993; 100(9): 1384-8.
  4. Pierro L, Camesasca FI, Mischi M, Brancato R. Peripheral retinal changes and axial myopia. Retina (Philadelphia, Pa) 1992; 12(1): 12-7.
  5. Xu L, Wang Y, Wang S, Wang Y, Jonas JB. High myopia and glaucoma susceptibility the Beijing Eye Study. Ophthalmology 2007; 114(2): 216-20.
  6. Pan CW, Cheng CY, Saw SM, Wang JJ, Wong TY. Myopia and age-related cataract: a systematic review and meta-analysis. American journal of ophthalmology 2013; 156(5): 1021-33.e1.
  7. Neuhann IM, Neuhann TF, Heimann H, Schmickler S, Gerl RH, Foerster MH. Retinal detachment after phacoemulsification in high myopia: analysis of 2356 cases. Journal of cataract and refractive surgery 2008; 34(10): 1644-57.
  8. Norregaard JC, Thoning H, Andersen TF, Bernth-Petersen P, Javitt JC, Anderson GF. Risk of retinal detachment following cataract extraction: results from the International Cataract Surgery Outcomes Study. The British journal of ophthalmology 1996; 80(8): 689-93.
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.
Cookies settings
Accept
Privacy & Cookie policy
Privacy & Cookies policy
Cookie name Active

Privacy Policy

What information do we collect?

We collect information from you when you register on our site or place an order. When ordering or registering on our site, as appropriate, you may be asked to enter your: name, e-mail address or mailing address.

What do we use your information for?

Any of the information we collect from you may be used in one of the following ways: To personalize your experience (your information helps us to better respond to your individual needs) To improve our website (we continually strive to improve our website offerings based on the information and feedback we receive from you) To improve customer service (your information helps us to more effectively respond to your customer service requests and support needs) To process transactions Your information, whether public or private, will not be sold, exchanged, transferred, or given to any other company for any reason whatsoever, without your consent, other than for the express purpose of delivering the purchased product or service requested. To administer a contest, promotion, survey or other site feature To send periodic emails The email address you provide for order processing, will only be used to send you information and updates pertaining to your order.

How do we protect your information?

We implement a variety of security measures to maintain the safety of your personal information when you place an order or enter, submit, or access your personal information. We offer the use of a secure server. All supplied sensitive/credit information is transmitted via Secure Socket Layer (SSL) technology and then encrypted into our Payment gateway providers database only to be accessible by those authorized with special access rights to such systems, and are required to?keep the information confidential. After a transaction, your private information (credit cards, social security numbers, financials, etc.) will not be kept on file for more than 60 days.

Do we use cookies?

Yes (Cookies are small files that a site or its service provider transfers to your computers hard drive through your Web browser (if you allow) that enables the sites or service providers systems to recognize your browser and capture and remember certain information We use cookies to help us remember and process the items in your shopping cart, understand and save your preferences for future visits, keep track of advertisements and compile aggregate data about site traffic and site interaction so that we can offer better site experiences and tools in the future. We may contract with third-party service providers to assist us in better understanding our site visitors. These service providers are not permitted to use the information collected on our behalf except to help us conduct and improve our business. If you prefer, you can choose to have your computer warn you each time a cookie is being sent, or you can choose to turn off all cookies via your browser settings. Like most websites, if you turn your cookies off, some of our services may not function properly. However, you can still place orders by contacting customer service. Google Analytics We use Google Analytics on our sites for anonymous reporting of site usage and for advertising on the site. If you would like to opt-out of Google Analytics monitoring your behaviour on our sites please use this link (https://tools.google.com/dlpage/gaoptout/)

Do we disclose any information to outside parties?

We do not sell, trade, or otherwise transfer to outside parties your personally identifiable information. This does not include trusted third parties who assist us in operating our website, conducting our business, or servicing you, so long as those parties agree to keep this information confidential. We may also release your information when we believe release is appropriate to comply with the law, enforce our site policies, or protect ours or others rights, property, or safety. However, non-personally identifiable visitor information may be provided to other parties for marketing, advertising, or other uses.

Registration

The minimum information we need to register you is your name, email address and a password. We will ask you more questions for different services, including sales promotions. Unless we say otherwise, you have to answer all the registration questions. We may also ask some other, voluntary questions during registration for certain services (for example, professional networks) so we can gain a clearer understanding of who you are. This also allows us to personalise services for you. To assist us in our marketing, in addition to the data that you provide to us if you register, we may also obtain data from trusted third parties to help us understand what you might be interested in. This ‘profiling’ information is produced from a variety of sources, including publicly available data (such as the electoral roll) or from sources such as surveys and polls where you have given your permission for your data to be shared. You can choose not to have such data shared with the Guardian from these sources by logging into your account and changing the settings in the privacy section. After you have registered, and with your permission, we may send you emails we think may interest you. Newsletters may be personalised based on what you have been reading on theguardian.com. At any time you can decide not to receive these emails and will be able to ‘unsubscribe’. Logging in using social networking credentials If you log-in to our sites using a Facebook log-in, you are granting permission to Facebook to share your user details with us. This will include your name, email address, date of birth and location which will then be used to form a Guardian identity. You can also use your picture from Facebook as part of your profile. This will also allow us and Facebook to share your, networks, user ID and any other information you choose to share according to your Facebook account settings. If you remove the Guardian app from your Facebook settings, we will no longer have access to this information. If you log-in to our sites using a Google log-in, you grant permission to Google to share your user details with us. This will include your name, email address, date of birth, sex and location which we will then use to form a Guardian identity. You may use your picture from Google as part of your profile. This also allows us to share your networks, user ID and any other information you choose to share according to your Google account settings. If you remove the Guardian from your Google settings, we will no longer have access to this information. If you log-in to our sites using a twitter log-in, we receive your avatar (the small picture that appears next to your tweets) and twitter username.

Children’s Online Privacy Protection Act Compliance

We are in compliance with the requirements of COPPA (Childrens Online Privacy Protection Act), we do not collect any information from anyone under 13 years of age. Our website, products and services are all directed to people who are at least 13 years old or older.

Updating your personal information

We offer a ‘My details’ page (also known as Dashboard), where you can update your personal information at any time, and change your marketing preferences. You can get to this page from most pages on the site – simply click on the ‘My details’ link at the top of the screen when you are signed in.

Online Privacy Policy Only

This online privacy policy applies only to information collected through our website and not to information collected offline.

Your Consent

By using our site, you consent to our privacy policy.

Changes to our Privacy Policy

If we decide to change our privacy policy, we will post those changes on this page.
Save settings
Cookies settings