晶狀體半脫位或脫位（Wills眼科手冊）
本文來(lái)自：尖峰眼科
晶狀體不在正常位置時(shí)該如何診治？
第十節 晶狀體半脫位或脫位
【定義】
1.晶狀體半脫位 晶狀體懸韌帶部分斷裂，晶狀體偏離中心區，但通過(guò)瞳孔仍可見(jiàn)到一部分。
2.晶狀體脫位 晶狀體懸韌帶完全斷裂，晶狀體完全偏離瞳孔區。
【癥狀】
視力下降；遮蓋一眼時(shí)，復視不消失，是為單眼復視。
【體征】
見(jiàn)圖13.10.1。
【主要體征】
晶狀體偏離中心或移位，虹膜震顫、晶狀體震顫。
【其他體征】
屈光度改變，嚴重的散光，白內障，瞳孔阻滯造成閉角型青光眼，獲得性高度近視，玻璃體進(jìn)人前房，前房深淺不一致。
【病因學(xué)】
1.外傷 最常見(jiàn)的原因，如果懸初帶斷裂超過(guò)25%則造成晶狀體半脫位。應排除其他的致病因素。
2.假性剝脫綜合征 絮片狀物質(zhì)如“靶”屏一樣位于晶狀體前囊，合并青光眼，瞳孔難以散大。由于懸韌帶無(wú)力，白內障手術(shù)中發(fā)生并發(fā)癥的風(fēng)險很高。
3.Marfan綜合征 雙眼晶狀體常向上方和顳側半脫位，視網(wǎng)膜脫離發(fā)生率升高。常染色體顯性遺傳，患有心肌病、主動(dòng)脈瘤、體型瘦長(cháng)、指(趾)長(cháng)，脊柱后側凸。
4.同型胱氨酸尿癥 雙眼晶狀體向下和鼻側半脫位。視網(wǎng)膜脫離發(fā)生率升高。為常染色體隱性遺傳。智力低下；骨骼畸形；體型與Marfan綜合征相似；血栓發(fā)生率高，特別是在全身麻醉時(shí)。輕癥患者的晶體半脫位可能是首發(fā)體征。
5.Weill-Marchesani綜合征 小的晶狀體可脫位入前房，引起可逆性的瞳孔阻滯。通常為常染色體隱性遺傳。短指，矮胖，癲癇發(fā)作，小球形晶狀體(晶狀體小而圓)，近視，無(wú)智力低下。
6.其他 獲得性梅毒、先天性晶體異位、無(wú)虹膜癥、Ethlers-Danlos綜合征(廣泛性彈力纖維發(fā)育異常Crouzon病、高賴(lài)氨酸血癥、亞硫酸鹽氧化酶缺乏癥、高度近視、慢性炎癥、過(guò)熟期白內障等。
【檢查】
1.病史 有無(wú)上述疾病的家族史?有無(wú)外傷?有無(wú)全身病，如梅毒、癲癇發(fā)作?
2.全面的眼科檢查 裂隙燈檢查，觀(guān)察是單側還是雙側發(fā)病，以及晶狀體移位的方向；檢查有無(wú)假性剝脫；囑患者轉動(dòng)眼球以觀(guān)察晶狀體是否有輕微的震顫。
3.請內科醫生做全身檢查 觀(guān)察體型、四肢、手、指(趾)。硝普鈉試驗或尿色譜分
析，以排除同型膀胱氨酸尿癥。超聲心動(dòng)圖檢查，在疑似Marfan綜合征的患者用以排除主動(dòng)脈瘤。
4.即使有明確的外傷史，也應做快速血漿反應素(RPR)和螺旋體抗體吸附熒光測定(FTA-ABS)檢查。
【治療】
1.晶狀體脫入前房 選擇以下方法之一。
(1)散瞳，囑患者仰臥，通過(guò)改變頭位，使晶狀體退入后房。必要時(shí)在表麻(如艾爾卡因)下用Zeiss前房角棱鏡或棉鑒輕壓角膜，使晶狀體復位。晶狀體進(jìn)入后房后，滴用0.5%~1%毛果蕓香堿縮瞳，并行周邊激光虹膜切開(kāi)術(shù)。
(2)手術(shù)摘除晶狀體：如果已形成顯著(zhù)的白內障、上述治療失敗、晶體再次脫位、使用毛果蕓香堿有不良反應者均需行手術(shù)摘除，并植入人工晶體。
2.晶狀體脫入玻璃體
(1)晶狀體囊膜完整，患者無(wú)癥狀、無(wú)炎癥，可隨訪(fǎng)觀(guān)察，或經(jīng)睫狀體平坦部行晶狀體切除術(shù)和人工晶體植入。
(2)晶狀體囊膜破裂、眼內炎癥，經(jīng)睫狀體平坦部行晶狀體切除術(shù)和人工晶體植入。
3.晶狀體半脫位
(l)無(wú)癥狀者，觀(guān)察。
(2)高度散光不能矯正或單眼復視：手術(shù)摘除晶狀體并植入人工晶體。
(3)有癥狀的白內障，可進(jìn)行如下治療：手術(shù)摘除晶體，散瞳(如0.25%東莨菪堿日1次)+無(wú)晶體眼視力矯正，縮瞳(如4%毛果蕓香堿凝膠，每晚睡前滴用)+有晶狀體眼的視力矯正，或大范圍的光學(xué)虹膜切除術(shù)(遠離晶狀體區)。
4.瞳孔阻滯 同無(wú)晶狀體性瞳孔阻滯的治療。參見(jiàn)第九章第十六節手術(shù)后青光眼。
5.如果懷疑Marfan綜合征 請心內科醫生對患者每年檢查一次超聲心動(dòng)圖，治療心臟病變?；颊呷粜枋中g(shù)或做牙齒治療，應預防性全身應用抗生素，以預防心內膜炎。
6.如果懷疑同型胱氨酸尿癥 請內科醫生診治。常規治療包括:
(1)吡哆醇(維生素B6)50~1000mg，口服，日1次。
(2)減少食物中的蛋氨酸，補充半胱氨酸。
(3)因可能出現血栓，應盡量避免手術(shù)。若必須手術(shù)，需要抗凝治療。
【隨訪(fǎng)】
隨訪(fǎng)間隔時(shí)間取決于致病原因、晶狀體脫位或半脫位的程度、癥狀。
13.10 Subluxed or Dislocated Crystalline Lens
Definition
Subluxation: Partial disruption of the zonular fibers. Lens is decentered but remains partially visible through the pupil.
Dislocation: Complete disruption of the zonular fibers. Lens is fully displaced out of the pupillary aperture.
Symptoms
Decreased vision, double vision that persists when covering one eye (monocular diplopia).
Signs
(See Figure 13.10.1.)
Critical.Decentered or displaced lens, iridodonesis (quivering of the iris), phacodonesis (quivering of the lens).
Other. Change in refractive error, marked astigmatism, cataract, angle-closure glaucoma as a result of pupillary block, acquired high myopia, vitreous in the anterior chamber, asymmetry of the anterior chamber depth.
Etiology
Trauma:Most common. Results in subluxation if >25% of the zonular fibers are ruptured. Need to rule out a predisposing condition (see other etiologies).
Pseudoexfoliation:Flaky material seen as scrolls in a “target pattern” on anterior lens capsule; associated with glaucoma; poor pupillary dilation; patients at higher risk of complications during cataract surgery due to weak zonules.
Marfan syndrome:Bilateral lens subluxation superiorly and temporally with increased risk for retinal detachment. Autosomal dominant with cardiomyopathy, aortic aneurysm, tall stature with long extremities and kyphoscoliosis.
Homocystinuria:Bilateral lens subluxation inferiorly and nasally. Increased risk of retinal detachment. Autosomal recessive with frequent mental retardation, skeletal deformities, high incidence of thromboembolic events (particularly with general anesthesia). Lens subluxation may be first manifestation in patients with mild disease.
Weill–Marchesani syndrome:Small lens can dislocate into the anterior chamber, causing reverse pupillary block. Often autosomal recessive with short fingers and stature, seizures, microspherophakia (small, round lens), myopia, no mental retardation.
Others:Acquired syphilis, congenital ectopia lentis, aniridia, Ehlers–Danlos syndrome, Crouzon disease, hyperlysinemia, sulfite oxidase deficiency, high myopia, chronic inflammations, hypermature cataract, others.
Work-Up
History: Family history of the disorders listed? Trauma? Systemic illness (e.g., syphilis, seizures)?
Complete ocular examination: Determine whether the condition is unilateral or bilateral and direction of displacement. Check for pseudoexfoliation. Evaluation for subtle phacodonesis by observing the lens during back and forth eye movement.
Systemic examination in conjunction with an internist: Evaluate stature, extremities, hands, and fingers; often in conjunction with an internist, including sodium nitroprusside test or urine chromatography to rule out homocystinuria and echocardiography to rule out aortic aneurysms in patients with possible Marfan syndrome.
RPR and FTA-ABS, even if there is a history of trauma.
Treatment
Lens dislocated into the anterior chamber.
—Dilate the pupil, place the patient on his or her back, and replace the lens into the posterior chamber by head manipulation. It may be necessary to indent the cornea after topical anesthesia with a Zeiss gonioprism or cotton swab to reposition the lens. After the lens is repositioned in the posterior chamber, constrict the pupil with pilocarpine 0.5% to 1% q.i.d. and perform a peripheral laser iridotomy.
or
—Surgically remove the lens (usually performed if a significant cataract is present, treatment described previously fails, recurrent dislocations occur, or there are compliance issues with pilocarpine) and consider placing an intraocular lens (IOL).
Lens dislocated into the vitreous.
—Lens capsule intact, patient asymptomatic, no signs of inflammation: Observe versus pars plana lensectomy/possible IOL.
—Lens capsule broken with intraocular inflammation: Pars plana lensectomy and/or possible IOL.
Subluxation.
—Asymptomatic: Observe.
—Uncorrectable astigmatism or monocular diplopia: Surgical removal of the lens and possible IOL placement.
—Symptomatic cataract: Options include surgical removal of the lens, mydriasis (e.g., scopolamine 0.25% q.d.) and aphakic correction, pupillary constriction (e.g., pilocarpine 4% gel q.h.s.) and phakic correction, or a large optical iridectomy (away from the lens).
Pupillary block: Treatment is identical to that for aphakic pupillary block. See 9.16, Postoperative Glaucoma.
If Marfan syndrome suspected: Refer the patient to a cardiologist for an annual echocardiogram and management of any cardiac-related abnormalities. Prophylactic systemic antibiotics are required if the patient undergoes surgery (or a dental procedure) to prevent endocarditis.
If homocystinuria is suspected: Refer to an internist. The usual therapy consists of:
—Pyridoxine (Vitamin B6) 50 to 1,000 mg p.o., q.d.
—Methionine restricted, cysteinesupplemented diet.
—Avoid surgery if possible because of the risk of thromboembolic complications. If surgical intervention is necessary, anticoagulant therapy is indicated.
Follow-Up
Depends on the etiology, degree of subluxation or dislocation, and symptoms.
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