醫學

不想戴眼鏡?快來瞭解視力矯正新趨勢

醫學

不想戴眼鏡?快來瞭解視力矯正新趨勢
文 / 台安醫院 黃峰霖醫師

不是每個人都適合做視力手術

眼球為一光學系統,其介質包括有角膜、前房、水晶體、玻璃體,而影響眼屈光最主要為角膜、水晶體的屈折力和眼球軸長,理論上若角膜或水晶體的屈折力太強或眼球軸太長或以上因素組合均可形成近視。

根據我們的觀察,近視發生年紀越小加深速度越快,變為高度近視的機會越高,導致失明的機會就越大。

因此近視的防治應從小做起,亦即絕不要讓發育的幼童太早過度使用眼力。近視度數太深的缺點,就是容易引起視網膜剝離,黃斑部出血等種種近視併發症。因此近視大於600度以上,宜定期做視網膜檢查,以防視網膜併發症的發生。

近視矯正的方法除了眼鏡、隱形眼鏡以外就是手術治療了。坊間也有所謂的角膜塑形術,其實也是一種硬式隱形眼鏡利用晚上睡覺時配戴,角膜因壓迫而變形達到矯正近視的效果,不過它只是一種暫時性矯正近視的方法,並無法有效根除與預防近視。

至於手術,由於科技的進步已由傳統的鑽石刀切割手術(RK),演進到雷射手術如Lasik,來矯正近視、遠視及散光,由於時間短、安全性高、不會疼痛、視力恢復快、準確度好對於長期戴眼鏡、隱形眼鏡不適者,提供另一項的選擇。

準分子雷射它是一種超紫外線的短波冷光雷射,能量高卻不具有穿透性,可以打斷角膜組織的分子鏈,達到改變角膜弧度矯正近視度數的目的,且不會造成眼球傷害,目前都是使用電腦控制,手術後的癒合情況也很好;所以患者不需要過於擔心因人為的安全性的問題,由於手術還是有其風險存在,因此手術前宜做詳細檢查與評估,才能達到最好的效果。

那些人才適合做手術

年滿18歲,一年內度數增加不超過50度以上,沒有合併眼睛疾病,如嚴重乾眼症、青光眼、白內障或網膜病變。

最佳矯正視力最好0.5以上、戴眼鏡、隱形眼鏡不適者。未罹患自體免疫系統疾病或結締組織疾病者、非孕婦、曾動過眼睛手術者但經醫師評估可進行手術者。


手術後可能會有的後遺症及須知

術後會有短期乾眼症。晚上出現眩光可能性會增加,多數一個月消失,少數可能會持續3至6個月,若有影響開車時宜暫停開車。

術後度數仍有可能回退,若度數回退太多,可再檢查角膜厚度,若厚度足夠眼球無其他禁忌,經醫師評估後可再次矯正。

術後一個月內不可游泳,眼部不要化妝,洗頭洗臉注意髒水不要進到眼內,以避免感染。

Lasik術後一個月內,避免用力揉眼睛及撞擊眼球以防角膜瓣脫離。

Lasik手術隔天可正常上班,但避免用眼過多工作及空氣污濁環境。


目前雷射手術準確度很高,只要與醫師配合好,手術時放鬆勿緊張,效果就會好,但手術仍有風險,因此建議戴眼鏡或隱形眼鏡不舒服或不方便時,才選擇手術矯正。

對於年近40歲以上者,術後仍會有老花眼的可能,看近距離吃力時仍要戴老花眼鏡。目前近視手術仍無法有效解決老花眼問題。

術後為確保手術安全無慮,建議術後定期回診檢查,隔天、一星期、一個月、3個月、6個月各檢查一次。

在手術前一定要先了解這些後遺症,慎選醫療院所,評估自我是否能接受這些風險,經醫師詳細檢查再考慮做手術。

本文作者【台安醫院 黃峰霖醫師】
本文由【KingNet國家網路醫院】提供


(A Practical Guide to Clinical Medicine)
  • Hooking Edge of the Liver

  • Place your right hand at the inferior and lateral border of the ribs, pushing down as you push up from behind with your left hand. If the right kidney is massively enlarged, you may be able to feel it between your hands.
  • Now examine the left upper quadrant. The normal spleen in not palpable. When enlarged, it tends to grow towards the pelvis and the umbilicus (i.e. both down and across). Begin palpating near the belly button and move slowly towards the ribs. Examine superficially and then more deeply. Then start 8-10 cm below the rib margin and move upwards. In this way, you will be able to feel enlargement in either direction. You can use your left hand to push in from the patient's left flank, directing an enlarged spleen towards your right hand. If the spleen is very big, you may even be able to "bounce" it back and forth between your hands. Splenomegaly is probably more difficult to appreciate then hepatomegaly. The liver is bordered by the diaphragm and can't move away from an examining hand. The spleen, on the other hand, is not so definitively bordered and thus has a tendency to float away from you as you palpate. So, examine in a slow, gentle fashion. The edge, when palpable, is soft, rounded, and rather superficial. Repeat the exam with the patient turned onto their right side, which will drop the spleen down towards your examining hand.
  • Exploration for the left kidney is performed in the same fashion as described for the right. Kidney pain, most commonly associated with infection, can be elicited on direct examination if the entire structure becomes palpable as a result of associated edema. This is generally not the case. However, as the kidney lies in the retroperitoneum, pounding gently with the bottom of your fist on the costo-vertebral angle (i.e. where the bottom-most ribs articulate with the vertebral column) will cause pain if the underlying kidney is inflamed. Known as costo-vertebral angle tenderness (CVAT), it should be pursued when the patient's history is suggestive of a kidney infection (e.g. fever, back pain and urinary tract symptoms).
  • test


    Laboratory and Imaging - Heart Sounds & Murmurs Exam - Physical Diagnosis Skills - University of Was

    Laboratory and Imaging: Heart Sounds & Murmurs

    Given the imperfect physical examination in diagnosing fluid overload and decreased left ventricular function, other studies are often helpful. These include radiography and echocardiography.

    Radiography

    Normal chest x-ray with normal pulmonary veins





    Click to see larger image and use back button to return to content.*

    Click to see larger image and use back button to return to content.*
    Chest x-ray with pulmonary edema

    Click to see larger image and use back button to return to content.*
    *Unless otherwise noted, all images are from the Cardiovascular Resources Videodisc.

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    Echocardiography

    Guidelines for Diagnostic Testing
    (American College of Cardiology / American Heart Association (AHA))
    Echocardiography Guidelines
    Murmurs in ASYMPTOMATIC Individuals
    Echocardiography Recommendation Murmur Heard
    Strong evidence or opinion in favor of Echo(I) Diastolic or continuous murmurs
    Holosystolic or late systolic murmurs
    Grade 3 or greater midsystolic murmurs
    Conflicting evidence or opinion but generally favoring (IIa) Murmurs associated with abnormal physical examination findings on cardiac exam
    Murmurs associated with abnormal EKG or chest x-ray
    Evidence or opinion that not useful or may be harmful Grade 2 or softer midsystolic murmur identified as innocent
    Murmurs in SYMPTOMATIC Individuals
    Echocardiography Recommendation Murmur Heard
    Strong evidence or opinion in favor of echo(I) Symptoms or signs of CHF, MI or syncope
    Symptoms or signs consistent with infective endocarditis or thromboembolism
    Conflicting evidence or opinion but generally favoring (IIa) Symptoms or signs most likely noncardiac but cardiac disease not excluded by standard evaluation.
    Evidence or opinion that not useful or may be harmful Symptoms or signs most likely non cardiac with an isolated midsystolic"innocent" murmur.

    Class I Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful or effective
    Class II Conditions for which there is conflicting evidence and/or divergence of opinion about the usefulness/efficacy of a procedure or treatment agreement that a given procedure or treatment is useful or effective
    Class IIa Weight of evidence/opinion is in factor of usefulness/efficacy
    Class IIb Usefulness/efficacy is less well established by evidence/opinion
    Class III Conditions for which there is evidence and/or general agreement that a given procedure is not useful and in some cases may be harmful

    About Yung-Hsiang Chang

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