晶状体半脱位或脱位（Wills眼科手册）
本文来自：尖峰眼科
晶状体不在正常位置时该如何诊治？
第十节 晶状体半脱位或脱位
【定义】
1.晶状体半脱位 晶状体悬韧带部分断裂，晶状体偏离中心区，但通过瞳孔仍可见到一部分。
2.晶状体脱位 晶状体悬韧带完全断裂，晶状体完全偏离瞳孔区。
【症状】
视力下降；遮盖一眼时，复视不消失，是为单眼复视。
【体征】
见图13.10.1。
【主要体征】
晶状体偏离中心或移位，虹膜震颤、晶状体震颤。
【其他体征】
屈光度改变，严重的散光，白内障，瞳孔阻滞造成闭角型青光眼，获得性高度近视，玻璃体进人前房，前房深浅不一致。
【病因学】
1.外伤 最常见的原因，如果悬初带断裂超过25%则造成晶状体半脱位。应排除其他的致病因素。
2.假性剥脱综合征 絮片状物质如“靶”屏一样位于晶状体前囊，合并青光眼，瞳孔难以散大。由于悬韧带无力，白内障手术中发生并发症的风险很高。
3.Marfan综合征 双眼晶状体常向上方和颞侧半脱位，视网膜脱离发生率升高。常染色体显性遗传，患有心肌病、主动脉瘤、体型瘦长、指(趾)长，脊柱后侧凸。
4.同型胱氨酸尿症 双眼晶状体向下和鼻侧半脱位。视网膜脱离发生率升高。为常染色体隐性遗传。智力低下；骨骼畸形；体型与Marfan综合征相似；血栓发生率高，特别是在全身麻醉时。轻症患者的晶体半脱位可能是首发体征。
5.Weill-Marchesani综合征 小的晶状体可脱位入前房，引起可逆性的瞳孔阻滞。通常为常染色体隐性遗传。短指，矮胖，癫痫发作，小球形晶状体(晶状体小而圆)，近视，无智力低下。
6.其他 获得性梅毒、先天性晶体异位、无虹膜症、Ethlers-Danlos综合征(广泛性弹力纤维发育异常Crouzon病、高赖氨酸血症、亚硫酸盐氧化酶缺乏症、高度近视、慢性炎症、过熟期白内障等。
【检查】
1.病史 有无上述疾病的家族史?有无外伤?有无全身病，如梅毒、癫痫发作?
2.全面的眼科检查 裂隙灯检查，观察是单侧还是双侧发病，以及晶状体移位的方向；检查有无假性剥脱；嘱患者转动眼球以观察晶状体是否有轻微的震颤。
3.请内科医生做全身检查 观察体型、四肢、手、指(趾)。硝普钠试验或尿色谱分
析，以排除同型膀胱氨酸尿症。超声心动图检查，在疑似Marfan综合征的患者用以排除主动脉瘤。
4.即使有明确的外伤史，也应做快速血浆反应素(RPR)和螺旋体抗体吸附荧光测定(FTA-ABS)检查。
【治疗】
1.晶状体脱入前房 选择以下方法之一。
(1)散瞳，嘱患者仰卧，通过改变头位，使晶状体退入后房。必要时在表麻(如艾尔卡因)下用Zeiss前房角棱镜或棉鉴轻压角膜，使晶状体复位。晶状体进入后房后，滴用0.5%~1%毛果芸香碱缩瞳，并行周边激光虹膜切开术。
(2)手术摘除晶状体：如果已形成显著的白内障、上述治疗失败、晶体再次脱位、使用毛果芸香碱有不良反应者均需行手术摘除，并植入人工晶体。
2.晶状体脱入玻璃体
(1)晶状体囊膜完整，患者无症状、无炎症，可随访观察，或经睫状体平坦部行晶状体切除术和人工晶体植入。
(2)晶状体囊膜破裂、眼内炎症，经睫状体平坦部行晶状体切除术和人工晶体植入。
3.晶状体半脱位
(l)无症状者，观察。
(2)高度散光不能矫正或单眼复视：手术摘除晶状体并植入人工晶体。
(3)有症状的白内障，可进行如下治疗：手术摘除晶体，散瞳(如0.25%东莨菪碱日1次)+无晶体眼视力矫正，缩瞳(如4%毛果芸香碱凝胶，每晚睡前滴用)+有晶状体眼的视力矫正，或大范围的光学虹膜切除术(远离晶状体区)。
4.瞳孔阻滞 同无晶状体性瞳孔阻滞的治疗。参见第九章第十六节手术后青光眼。
5.如果怀疑Marfan综合征 请心内科医生对患者每年检查一次超声心动图，治疗心脏病变。患者若需手术或做牙齿治疗，应预防性全身应用抗生素，以预防心内膜炎。
6.如果怀疑同型胱氨酸尿症 请内科医生诊治。常规治疗包括:
(1)吡哆醇(维生素B6)50~1000mg，口服，日1次。
(2)减少食物中的蛋氨酸，补充半胱氨酸。
(3)因可能出现血栓，应尽量避免手术。若必须手术，需要抗凝治疗。
【随访】
随访间隔时间取决于致病原因、晶状体脱位或半脱位的程度、症状。
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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