淚器結構 Blocked Tear Duct (Nasolacrimal Duct Obstruction)

A blocked tear duct occurs when your nasal passageways cannot properly drain tear liquid from your eyes. 
You may have itchy, irritated or watery eyes. 
Sometimes, babies are born with blocked tear ducts. 
A clogged tear duct may heal on its own, or you may need surgery. 
With treatment, most people experience total symptom relief. 
Overview
 What is a blocked tear duct?
The tears that moisturize your eye drain through a tiny opening in the corner of your eye. 
The liquid enters your nose, where your body absorbs and disposes of it.
A blocked tear duct is a full or partial obstruction (blockage) in the nasal (nose) passageways that drain tears. 

If you have a blocked tear duct, your eyes may be itchy, irritated and watery. 
Another name for a blocked tear duct is nasolacrimal duct obstruction. 
Lacrimal refers to tears.
 How does the tear system work?
Typically, your tear system keeps your eyes slightly wet but not too watery. 
Your tear system has three parts:
Lacrimal glands create tears.
Puncta are small openings at your eye corner where tears flow out.
Nasolacrimal ducts connect to the puncta and drain the rest of your tear fluid into the nose.
 What are the tear ducts?
Tear ducts are another name for the nasolacrimal ducts. 
They form at the corner of your eye nearest your nose. 
They run underneath the skin and connect to your facial bones and nose.
 How does a clogged tear duct affect my body?
When you have a clogged tear duct, tears can’t drain into the nose through the nasolacrimal ducts. 
Instead, your tears stay in your eye. 
The result is uncomfortable, watery eyes.
 What is a partial tear duct blockage?
Sometimes, a narrow tear duct (dacryostenosis) can lead to a partial tear duct blockage. 
When you have a partial blockage, your tears may build up and not drain properly. 
This tear buildup can lead to infection. 
If you have a partial blockage, your provider will likely use similar treatments as a full blockage.
 Who might get a blocked tear duct?
Blocked tear ducts are common in newborns. 
Usually, a blocked tear duct in a baby goes away without treatment.
Adults are more likely to develop a tear duct blockage if they have:
Chronic eye inflammation, such as uveitis.
Glaucoma.
History of eye or sinus surgery.
Previous cancer treatment, such as radiation therapy or chemotherapy.
Symptoms and Causes
 What causes a blocked tear duct?
Blocked tear ducts can happen to anyone of any age. 
Causes of blocked tear ducts include:
Age: As you get older, your puncta may naturally narrow.
Congenital blockages: Some babies are born with tear ducts that are narrow or not fully formed (dacryostenosis).
Infection: Chronic sinus infections or eye infections can lead to blockage.
Injury: Any eye injury near the tear ducts, even a scrape from tiny dirt particles, can cause a blockage.
Tumors: A tumor anywhere near the tear ducts, such as in the nose, can cause blocked tear ducts.
 What are the symptoms of a blocked tear duct in adults?
The most common sign of a blocked tear duct is watery eyes or excessive tearing. 
You may also experience:
Blurred vision.
Crusting around the eyelids.
Drainage, such as mucus or pus around the eyes.
Redness in the white part of your eye.
Swelling near your eye’s inner corner.
 What are the symptoms of a blocked tear duct in infants?
Babies don’t start making tears until they are a few weeks old. 
You may not notice a blocked tear duct in a newborn right away. 
As babies get older, blocked tear duct symptoms might include:
Redness around the eye, usually from your baby rubbing the eye.
Tears draining down the baby’s cheek instead of out of the eye corner.
Tears pooling near the corner of the eye but not draining.
Yellowish discharge or mucus in the baby’s eye.
Diagnosis and Tests
 What tests can help diagnose a blocked tear duct?
To diagnose a blocked tear duct, your healthcare provider asks about your symptoms. 
Your provider may also use tests that examine the eyes and nose, including: 
Tear drainage test: Your provider places one drop of dye on each eye. 
If the dye does not drain from your eye, it could mean you have a blocked tear duct. 
Eye imaging: Your provider puts a special, safe dye in your eye. 
This dye travels through your tear drainage system. 
It shows up on an X-ray, CT scan or MRI to help your provider find the blockage. 
Irrigation and probing: Irrigation uses a fluid to clean out your tear ducts. 
Your provider may insert a small instrument through the corner of your eye to find the obstruction.
Management and Treatment
 What is the treatment for a blocked tear duct in adults?
Blocked tear duct treatment depends on the cause. 
For example, if you have a tumor, your treatment focuses on removing or shrinking the tumor. 
Additional treatment options may include: 
Medications: If an eye infection caused the blockage, your provider may prescribe oral antibiotics or medicated eyedrops.
Dilation, probing and flushing: Your provider enlarges the opening at the corner of your eye. 
Then, using a small probe, your provider sends fluid through the tear duct. 
Usually, this “flushing” removes the blockage at least temporarily. 
Stenting: Your provider places a small, hollow tube (stent) through the puncta and into the tear duct. 
The tube allows tears to drain properly. 
The tubes stay in place for about three months. 
You will see a small portion of the tube out of the corner of your eye. 
Balloon catheter dilation: Your provider places a small, deflated balloon into the tear duct. 
Then your provider inflates the balloon a few times to clear the blockage. 
You are usually under general anesthesia (medication to help you remain asleep) for this procedure. 
Snip punctoplasty: Your provider makes two or three small incisions around your puncta. 
These incisions create a larger tear duct opening. 
Snip punctoplasty is a common treatment for partial blockages. 
 What is dacryocystorhinostomy for blocked tear ducts?
If less-invasive options don’t bring relief, your provider may recommend surgery. 
Providers usually use dacryocystorhinostomy (DCR). 
This procedure creates a new route to drain tears into your nose. 
On the day of surgery, you receive anesthesia to help you stay calm and numb during the operation. 
During the procedure, your surgeon: 
Creates a connection between your lacrimal sac and nose. 
The surgeon may use small incisions or place tools through the nose.
Places stents (small, hollow tubes) to hold open the new route as it heals.
A dacryocystorhinostomy is usually an outpatient surgery, meaning you can go home the same day. 
Typically, your surgeon removes the stents after three to four months. 
 What is the treatment for a blocked tear duct in babies?
Often, a blocked tear duct in a newborn resolves without treatment. 
In the first few months of life, the baby’s tear ducts may mature and get rid of the blockage. 
Sometimes, a baby still has a small piece of tissue blocking the flow of tears inside the nose. 
Your baby’s provider may teach you a special eyelid massage technique. 
This massage helps open the tissue so tears can drain as they should. 
If a watch-and-wait approach does not work, providers may use dilation and flushing, balloon catheters or stents. 
These treatments work the same way in babies as they do in adults. 
However, providers use general anesthesia to keep babies still and calm during the procedure.
Prevention
How can I prevent a blocked tear duct?
The best way to avoid a blocked tear duct is to get care right away for eye problems, such as inflammation, infection or injury. 
To prevent eye inflammation or infections: 
Avoid rubbing or excessively touching your eyes. 
Avoid sharing eye products, such as eyedrops or cosmetics. 
Clean contact lenses according to your eye doctor’s instructions.
Replace cosmetics, such as mascara, eyeliner or eyeshadow, every three to six months. 
Wash your hands frequently and thoroughly.
Outlook / Prognosis
What is the outlook for blocked tear ducts?
If the blocked tear duct is because of an injury, it usually clears up on its own once the injury heals. 
Blocked tear ducts in babies often open up in time or with home care. 
People who receive blocked tear duct treatment typically have an excellent outlook. 
In particular, dacryocystorhinostomy has around a 90% success rate. 
Most people don’t have any further symptoms after treatment.
A note from Cleveland Clinic
Blocked tear ducts occur when your nasolacrimal passages cannot drain tears as they should. 
If you have a blocked tear duct, you may have watery, irritated eyes. 
Some newborns have blocked tear ducts that often heal without treatment. 
In adults, treatment may include flushing out the tear duct or surgery. 
Treatment completely relieves symptoms for most people.
 淚器的結構和溢淚症的成因


淚水有滋潤、過濾、補充養份、保護眼角膜和保持視力清的作用，與眼睛的健康息息相關。
淚腺 (Lacrimal Gland) 位於眼眶外上方淚器窩內，負責分泌淚液。
排淚的淚道包括淚小點 (Punctum)、淚小管 (Canaliculus)、淚囊 (Lacrimal Sac) 和鼻淚管 (Nasolacrimal Duct)。
正常情況下，淚液從淚腺分泌，入結膜囊後經淚道的引流進入上下眼瞼內側端的淚小點，跟淚小管連結，並匯合於淚囊，再流至鼻淚管，最後入鼻腔內而從喉嚨排走。
淚水分泌過多和淚道阻塞均會導致淚液引流不及，使淚液溢於眼眶外，臨床稱之為溢淚症。
眼球感染、發炎、沙眼、敏感、眼瞼內翻等各類刺激，都會增加淚液。
而鼻淚管或涙小管阻塞或收窄、鼻瘜肉、眼瞼外翻等，則會導致排出受阻。
這好比道路渠道的運作，在傾盤大雨過後，或渠道堵塞的情況下，往往難以避免雨水泛濫。
 何謂急性淚囊炎
急性淚囊炎 (Acute Dacryocystitis) 是指淚囊數天內含膿發炎，伴隨眼睛與鼻樑之間的急性紅、熱、疼痛的囊腫腫脹。
除了退化性鼻淚管阻塞之外， 急性淚囊炎的原因還有淚囊外傷、淚道探通中造成假道，或在淚囊手術後細菌感染。
急性淚囊炎病發時，淚囊區皮膚變得紅腫熱痛，並向下瞼、鼻根及頰部蔓延。
其他常見徵狀包括結膜充血水腫、溢淚加劇、淚小點溢膿、耳前和颚下淋巴結腫大和壓痛等。
在膿腫比較嚴重時，更可以從皮膚表面爆破，在面部形成一條瘘道 (Fistula)。
更罕有的併發症包括引起鄰近的眼腔蜂窩組織炎 (Orbital Cellulitis)，若不及時治療可以導致複視和視力下降。
 處理急性淚囊炎 不能坐以待斃
急性淚囊炎患者都需要滴抗生素眼藥水和服用口服抗生素。
嚴重患者更可能需要靜脈抗生素注射。
若囊腫持續，醫生可能需要在表皮上剖開淚囊(Incision and drainage) 或以小探針放膿。
急性發炎過後，淚道探通檢查 (Probing and Syringing) 可以幫忙檢查淚道是否通暢及確定阻塞部位。
醫生會將一枝載有生理鹽水的小探管經淚小孔注入淚小管。
若鹽水未能到達喉嚨，即鼻淚管阻塞，並需要再用儀器斷定阻塞的位置。
淚囊鼻腔吻合術 (Dacryocystorhinostomy) 是鼻淚管阻塞的最終治療，將局部鼻腔黏膜和淚囊通過手術接合在一起，建立一條新的引流淚液通道。
現代微創淚管手術利用內窺鏡於鼻腔內進行淚囊鼻腔吻合，沒有外在疤痕，而且過程可以全身或局部麻醉， 比傳統的淚管手術外觀更勝一酬，且成功率相若（九成以上）。
 淚囊按摩五步曲
淚管長期阻塞，會使淚水和分泌物大量貯留於淚囊， 引致淚囊擴張，形成淚囊黏液囊腫 (Mucocele)。
病徵除了長期淚水溢出外， 在眼睛與鼻樑之間會出現一個囊腫， 用手按壓淚囊區域會有黏液性分泌物自淚小孔流出， 間中亦會有紅眼症的症狀。
長期積聚淚液，會成為細菌生長、繁殖的場所。
若久不處理，可以引發急性淚囊炎。
因此，勤力地按摩淚囊可以幫助滯留在內的分泌物排出，減少淚囊發炎的機會。
清潔雙手及將指甲剪短後，可以用以下方法按摩淚囊：
1. 將食指按於面頰近鼻孔側位置，向上推壓至眼角旁近鼻樑處，按摩淚囊部位
2. 重覆以上動作20至30次
3. 如有分泌物排出，可用棉花球及凍開水清潔眼睛
4. 如有處方眼藥，完成按摩後才使用
5. 每天按摩3至4次
 防患於未然
鼻淚管阻塞會引起溢淚症及慢性淚囊炎，而細菌的滋生繁殖更可以引起急性淚囊炎。
所謂病向淺中醫，若你經常溢淚，甚至發現淚小點溢膿和淚囊區發痛，請及早諮詢你的眼科醫生，不要輕視徵狀。


淚水有滋潤、過濾、補充養份、保護眼角膜和保持視力清的作用，與眼睛的健康息息相關。
淚腺 (Lacrimal Gland) 位於眼眶外上方淚器窩內，負責分泌淚液。
排淚的淚道包括淚小點 (Punctum)、淚小管 (Canaliculus)、淚囊 (Lacrimal Sac) 和鼻淚管 (Nasolacrimal Duct)。

正常情況下，淚液從淚腺分泌，入結膜囊後經淚道的引流進入上下眼瞼內側端的淚小點，跟淚小管連結，並匯合於淚囊，再流至鼻淚管，最後入鼻腔內而從喉嚨排走。
淚水分泌過多和淚道阻塞均會導致淚液引流不及，使淚液溢於眼眶外，臨床稱之為溢淚症。
眼球感染、發炎、沙眼、敏感、眼瞼內翻等各類刺激，都會增加淚液。

而鼻淚管或涙小管阻塞或收窄、鼻瘜肉、眼瞼外翻等，則會導致排出受阻。
這好比道路渠道的運作，在傾盤大雨過後，或渠道堵塞的情況下，往往難以避免雨水泛濫。