眼科檢查到底在做什麼？
一篇看懂視力、眼壓、眼底大小事 What Exactly Happens During an Eye Exam?
A Guide to Vision, Eye Pressure, and Retinal Health

第一步：你的「視力」到底好不好？ Step 1: How Good Is Your Vision?

任何眼科檢查都始於量化您的視覺能力。 Every eye exam begins with a quantitative measurement of your visual ability.

• 視力檢查 (Visual Acuity)：這就是最經典的「比C」或「看E」的視力表檢查，用來測量您看遠看近的清晰度。所謂「20/20」的視力，代表您在20英尺處能看清的東西，一個正常視力者在20英尺處也能看清。如果是「20/40」，則代表您需要站到20英尺處，才能看清正常人在40英尺處就能看清的東西。 Visual Acuity: This is the classic eye chart test where you read letters or shapes to measure the sharpness of your distance and near vision. “20/20” vision means you can see at 20 feet what a person with normal vision can see at 20 feet. “20/40” means you need to be at 20 feet to see what a person with normal vision can see at 40 feet.
• 屈光檢查 / 驗光 (Refraction)：這就是大家最熟悉的「1號和2號哪個比較清楚？」的環節。驗光師會用綜合驗光儀，找出最適合您的鏡片度數，以矯正近視、遠視或散光。 Refraction: This is the familiar “Which is clearer, 1 or 2?” part of the exam. The optometrist uses a phoropter to find the ideal lens prescription to correct for nearsightedness, farsightedness, or astigmatism.

第二步：用「裂隙燈」把眼睛看個仔細 Step 2: A Closer Look with the Slit Lamp

在確定了基礎視力後，醫生會使用一系列儀器來詳細檢查您眼睛的結構。 After assessing basic vision, the doctor uses a series of instruments for a detailed examination of your eye’s structure.

裂隙燈生物顯微鏡檢查 Slit Lamp Bio-microscopy

這是眼科檢查的核心工具，您可以把它想像成一台給眼睛用的「超級顯微鏡」。您需要將下巴和額頭靠在儀器上，醫生就能透過高倍率的立體視野，從前到後，仔細檢查您的眼瞼、角膜、虹膜、水晶體等精細結構。 This is a core tool in eye exams, which you can think of as a “super microscope” for the eye. You rest your chin and forehead on the machine, and the doctor can use a magnified, three-dimensional view to meticulously examine your eyelids, cornea, iris, lens, and other delicate structures from front to back.

眼壓測量 (Tonometry) Tonometry (Eye Pressure Test)

這是用來測量「眼內壓」(IOP) 的檢查，眼壓過高是青光眼的主要風險因子。常見的方法有： This test measures your “intraocular pressure” (IOP), as high eye pressure is the primary risk factor for glaucoma. Common methods include:

• 非接觸式眼壓計 (NCT)：俗稱「噴氣式」，儀器會向您的角膜噴出一股氣流來測量眼壓，是一種快速的篩檢工具。 Non-Contact Tonometer (NCT): Nicknamed the “air-puff test,” this instrument releases a puff of air onto your cornea to measure eye pressure. It’s a quick screening tool.
• 高曼壓平式眼壓計 (GAT)：這是國際公認的「黃金標準」。在點了麻醉和螢光劑眼藥水後，醫生會用一個測壓頭輕觸您的角膜進行精準測量。 Goldmann Applanation Tonometer (GAT): This is the internationally recognized “gold standard.” After numbing drops and a fluorescent dye are applied, the doctor gently touches your cornea with a probe for an accurate measurement.

進階檢查：角膜的「精密身體檢查」 Advanced Tests: The Cornea’s “Thorough Checkup”

對於需要進行屈光手術或有特殊角膜問題的人，醫生會進行更深入的檢查。 For people who need refractive surgery or have specific corneal issues, doctors will perform a more in-depth examination.

• 角膜地形圖：像繪製「3D地圖」一樣，詳細分析您角膜表面的形狀和曲率，是LASIK等手術前的必備項目。 Corneal Topography: Like creating a “3D map,” this test provides a detailed analysis of your cornea’s shape and curvature and is essential before procedures like LASIK.
• 角膜厚度測量：角膜的厚度會影響眼壓測量的準確性。一個較厚的角膜可能會讓眼壓讀數「虛胖」，反之亦然。 Corneal Pachymetry: The thickness of the cornea affects the accuracy of eye pressure measurements. A thicker cornea can give an artificially high reading, and vice versa.
• 角膜內皮細胞顯微鏡：檢查角膜後方一層無法再生的「幫浦細胞」，它們負責維持角膜的清澈。在白內障手術前評估這層細胞的健康狀況非常重要。 Specular Microscopy: This test examines the health of the “pump cells” on the back layer of the cornea, which cannot regenerate and are responsible for keeping the cornea clear. Assessing the health of these cells is crucial before cataract surgery.

第三步：「散瞳」一窺眼底的秘密 Step 3: Dilating Your Pupils to Uncover Retinal Secrets

為了清楚地看到眼球後方的視網膜、視神經和血管，醫生通常需要幫您「散瞳」。 To get a clear view of the retina, optic nerve, and blood vessels at the back of the eye, a doctor will often need to “dilate” your pupils.

眼底攝影 Fundus Photography

散瞳後，醫生常會用「眼底照相機」為您的視網膜拍攝一張高解析度的數位照片。這就像是為您的眼底健康拍下一張「存證照」，建立一個永久、客觀的紀錄，對於未來追蹤比較微小的變化至關重要。 After dilation, the doctor will often use a “fundus camera” to take a high-resolution digital photograph of your retina. This is like taking an “evidence photo” of your retinal health, creating a permanent, objective record that is crucial for tracking subtle changes over time.

高科技儀器：眼科的「電腦斷層」與「血管攝影」 High-Tech Instruments: The “CT Scan” and “Angiography” of the Eye

當需要更深入的資訊時，醫生會使用更高階的影像技術。 When more detailed information is needed, doctors use advanced imaging technologies.

• 光學同調斷層掃描 (OCT)：被譽為「眼睛的光學斷層掃描」。它利用光波，能拍攝出視網膜和視神經的超高解析度「剖面圖」，讓我們能看到視網膜的各個分層。對於診斷青光眼和黃斑部病變，這是不可或動的利器。 Optical Coherence Tomography (OCT): Known as the “optical CT scan of the eye.” It uses light waves to capture ultra-high-resolution “cross-sectional” images of the retina and optic nerve, allowing us to see the various retinal layers. This is an indispensable tool for diagnosing glaucoma and macular degeneration.
• 眼部超音波：當醫生的視線被擋住時（例如有非常嚴重的白內障或玻璃體出血），就需要用「超音波」來探測眼球後方的結構，就像用聲波來看路。 Ocular Ultrasound: When the doctor’s view is obstructed (e.g., by a severe cataract or vitreous hemorrhage), an “ultrasound” is needed to probe the structures at the back of the eye, like using sound waves to navigate a path.
• 螢光眼底血管攝影 (FA)：這是一項動態檢查。從手臂靜脈注射顯影劑後，用相機連續拍攝顯影劑流經視網膜血管的過程，能精準找出血管是否有滲漏、阻塞或異常增生。 Fluorescein Angiography (FA): This is a dynamic test. After a dye is injected into a vein in your arm, a camera takes a series of rapid photos as the dye flows through the retinal blood vessels. This precisely identifies any leakage, blockages, or abnormal new vessel growth.

第四步：檢查眼睛與大腦的「連線品質」 Step 4: Checking the “Connection Quality” Between Your Eyes and Brain

最後，還需要評估您的眼睛如何與大腦溝通，以及雙眼如何協同工作。 Finally, your doctor will assess how your eyes communicate with your brain and how they work together.

• 視野檢查：這是在一台碗狀儀器中進行的檢查，用來繪製您完整的視覺範圍圖，也就是測試您的「餘光」是否正常。這是診斷和追蹤青光眼的基石。 Visual Field Test: This exam, performed in a bowl-shaped instrument, maps your complete visual field, testing if your “peripheral vision” is normal. This is a cornerstone for diagnosing and monitoring glaucoma.
• 眼球運動與遮蓋測試：醫生會讓您用眼睛追蹤物體，並進行經典的「遮眼測試」，來檢查控制眼球的六條肌肉功能是否正常，以及雙眼是否有協調對位，排除斜視（鬥雞眼）等問題。 Ocular Motility and Cover Test: The doctor will have you follow an object with your eyes and perform the classic “cover test” to check if the six muscles that control eye movement are functioning correctly and if both eyes are aligned, ruling out issues like strabismus (crossed eyes).