全麻下儿童后发性白内障Nd:YAG激光治疗的临床效果

目的探讨氯胺酮全麻下Nd∶YAG激光治疗儿童后发性白内障的临床效果。方法对23例(26眼)儿童后发性白内障在氯胺酮全麻后应用Nd∶YAG激光进行后囊切开,术后随访6个月,观察并分析术后视力及并发症情况。结果激光截囊成功率100%,术后视力提高21眼(80.77%),稳定5眼(19.23%),无视力下降者。并发症有前房积血3眼,人工晶状体损伤6眼,前房炎症反应7眼,眼压升高2眼。结论对不能配合的儿童后发性白内障,在氯胺酮全麻下行Nd∶YAG激光后囊切除术是一种安全有效的治疗方法。     

后发性白内障Nd:YAG激光治疗的分析

目的：观察Nd：YAG激光对各类白内障术后的后发性白内障的疗效、治疗参数和并发症。

方法：对360例382眼各类白内障术后的后发性白内障Nd：YAG激光治疗。观察术后视力及并发症。分1级膜、2级膜和3级膜三组统计激光参数以及分老年性、先天性、并发性和外伤性白内障术后后发性白内障四组统计激光参数进行对照分析。

结果：治疗前后最佳矫正视力比较有显著性差异(P<0.05)。老年性组与外伤性组使用的平均激光总能量和平均激光脉冲数比较均有显著性差异(P<0.05)。并发症包括激光治疗后7眼眼压升高(1.8%),人工晶状体损伤26眼(7.7%)。

结论：Nd：YAG激光是治疗后发性白内障安全有效的方法。外伤性白内障术后发生后囊膜混浊的病例多为3级膜,Nd：YAG激光治疗时使用单次能量,总脉冲数和激光总能量均大。针对患者的情况选择好激光治疗参数,及时处理术后并发症,能提高治疗的有效性和安全性。     

儿童后发性白内障的Nd:YAG激光治疗

目的评价Nd:YAG激光治疗儿童后发性白内障的疗效及安全性,探讨防止其并发症的有效方法.方法对58例68眼儿童后发性白内障行Nd:YAG激光后囊膜切开术,随访观察8～26个月,平均18个月,并进行分析讨论.结果截囊成功率100%,所有患儿视力均有不同程度提高;术后眼压暂时性升高4眼(5.9%),轻度人工晶状体损伤6眼(8.8%).结论 Nd:YAG激光后囊膜切开术治疗儿童后发性白内障安全、简便、有效,做到准确瞄准和聚焦,低能量、少击射次数,后囊膜切口大小适当,能有效地防止其并发症的产生.     

先天性白内障的综合治疗

目的 探讨先天性白内障的综合治疗方法和疗效观察。方法 22例42眼先天性白内障分别行白内障超声乳化吸出联合人工晶体植入术，白内障超声乳化吸出联合后囊撕囊，白内障超声乳化吸出联合人工晶体植入及格栅状虹膜植入术，术后出现后发障行Nd：YAG激光治疗。患者随访12～36个月并观察视力情况。结果 22例42眼中，有20例（40眼）术后视力明显提高。10例18眼行Nd：YAG激光治疗后发障安全有效。结论 先天性白内障患儿应尽早手术，小于3．5岁患儿术后应长期配戴框架眼镜、弱视训练。婴幼儿行Nd：YAG激光治疗后发障方便易行，并发症少。     

Nd:YAG激光治疗后发障167例临床观察

目的 探讨Nd：YAG激光治疗后发障的技术、效果及并发症。方法 用Nd：YAG激光对不同类型白内障手术治疗后并发后发障患者167例(174只眼)进行了治疗。结果 所有患者术后随访4～24个月，174只眼中170只眼术后视力有不同程度提高，增视率97．7％，4例视力不提高者患有不同类型的眼底疾病，未见严重并发症发生。结论 Nd：YAG激光后囊膜切开术治疗后发障操作简易、安全且疗效确切，但术中应准确聚焦和严格掌握激光能量，避免严重并发症发生。     

Nd∶YAG激光治疗后发性白内障的临床评价

目的:评价Nd∶YAG激光治疗后发性白内障的临床疗效、安全性及治疗要点。方法:对723例770眼明显影响视力的后发性白内障患者用Nd∶YAG激光进行治疗,根据患者的不同情况选择术前处理方式,切开能量以切开囊膜的最小能量开始。结果:一次截囊成功率99.1%;所有患者术后随访4～12mo,术后视力均明显提高,由术前平均视力0.22提高到0.50。并发症有人工晶状体小凹86眼(11.2%),一过性眼压升高7眼(0.9%),玻璃体疝2眼(0.3%)。结论:Nd∶YAG激光后囊膜切开术治疗后发性白内障安全且疗效肯定;掌握治疗时机,针对患者的具体情况选择术前处理方式能提高治疗的效果及安全性。     

Nd:YAG激光治疗后发障的临床研究

目的:探讨Nd:YAG激光治疗后发障的疗效和方法。方法:应用Nd:YAG激光仪,对325例(325眼)后发障患者行后囊膜切开术,术后随访时间3mo。结果:激光截囊前后视力有显著性差异(P <0.01),而激光截囊后与后发障发生前视力无显著差异(P > 0.05),人工晶状体损伤47例(17.3%),但对视力预后无明显影响。结论:Nd:YAG激光治疗应采用合适的激光方法和能量,能较大程度地提高视力,且并发症发生率低,是治疗后发障最有效的方法。     

Nd:YAG激光治疗后发性白内障的临床评价

目的:评价Nd:YAG激光治疗后发性白内障的临床疗效、安全性及治疗要点.方法:对723例770眼明显影响视力的后发性白内障患者用Nd:YAG激光进行治疗,根据患者的不同情况选择术前处理方式,切开能量以切开囊膜的最小能量开始.结果:一次截囊成功率99.1%;所有患者术后随访4～12mo,术后视力均明显提高,由术前平均视力0.22提高到0.50.并发症有人工晶状体小凹86眼(11.2%),一过性眼压升高7眼(0.9%),玻璃体疝2眼(0.3%).结论:Nd:YAG激光后囊膜切开术治疗后发性白内障安全且疗效肯定;掌握治疗时机,针对患者的具体情况选择术前处理方式能提高治疗的效果及安全性.     

Nd:YAG激光治疗人工晶状体术后后发障的分析

目的 探讨Nd：YAG激光治疗人工晶状体植入术后后发障的方法和效果。方法 应用Nd：YAG激光机。对400例后发障行激光后囊切开术。结果 切开术成功率为100％，视力增加者96．75％。结论 激光治疗后发障视力提高显著。     

Nd：YAG激光治疗后发性白内障的时机的探讨

目的 探讨Nd:YAG激光治疗后发性白内障的最佳时机。方法 对20例（22眼）白内障术后后发障形成的不同时间行Nd:YAG激光治疗。人工晶状体与后囊间存在微小间隙者，自视轴中心开始做离心击射；若后囊有张力线，先垂直张力线切开。人工晶状体紧贴后囊者，将爆破焦点置于后囊平面后，自视轴区外开始做向心击射。在后发性白内障形成后的不同时间进行激光治疗，并分组统计比较其治疗效果。结果 后发障形成后3～6月，治疗所需激光能量最低，视轴区囊碎片小，易吸收，眼前飞蚊症发生率低。结论 白内障术后成人后发性白内障Nd:YAG激光治疗的最佳时机为其形成后的3～6月，儿童后发性白内障应尽早进行激光治疗，以促进视功能恢复。     

Homeostasis of the retinal micro-environment: I. Magnesium,potassium and calcium distributions in the avian eye

The concentrations of Mg²⁺, K⁺ and Ca²⁺ in the intraocular fluids (IOFs) and blood plasma of chickens and pigeons were determined by atomic absorption spectrophotometry. The Mg²⁺ concentration in the IOFs of both species was greatest in the liquid vitreous adjacent to the retina followed by aqueous > blood plasma > plasma dialysate. In contrast the concentration of K⁺ in the IOFs of both chickens and pigeons was greater in the aqueous than in the liquid vitreous. The concentrations of Ca²⁺ in all IOF compartments of chicken eyes were virtually identical and were lower than that of blood plasma. The concentrations of Mg²⁺ in the IOFs of the chicken, especially in the liquid vitreous, was remarkably stable; experimentally lowering or raising the plasma Mg²⁺ concentration over a relatively wide range had little or no effect on the Mg²⁺ concentration in the IOFs of these animals. We can conclude that a high Mg²⁺ and low K⁺ concentration in the extracellular fluids of the retina is maintained in the avian eye, as in the mammalian eye, by active transport processes across the blood-retinal barrier systems. Because the avian retina is completely avascular, the site of these homeostatic transport processes must be the epithelium of the retinal choroid and/or the pecten. These findings support the concept that the contribution of the vitreous to the homeostasis of the retinal micro-environment is inversely related in vertebrates to the degree of retinal vascularization.     

Vergleich der Durchmesserreaktion retinaler Arterien und Venen auf Flickerlicht

ZusammenfassungZiel In dieser Studie soll die durch Flickerlicht verursachte Durchmesserreaktion retinaler Arterien und Venen hinsichtlich Ausmaß und zeitlichem Ablauf verglichen werden.Methoden In die klinische Studie wurden 26 gesunde Probanden einbezogen. Der Durchmesser der retinalen Gefäße jeweils eines Auges wurde kontinuierlich mittels eines Retinal vessel analyzer gemessen. Jede Untersuchung bestand aus 100 s Baseline sowie 5 Perioden von 20 s Flickerlichtstimulation, gefolgt von 80 s Beobachtung.Ergebnisse Unmittelbar nach Flickerlicht dilatierten die Arterien um 6,9±2,8% (MW±STD) und die Venen um 6,5±2,8% (Unterschied nicht signifikant). Der Quotient aus arterieller und venöser Dilatation (AVDQ) betrug 1,25±0,69 (Spannweite 0,2 bis 2,8). Es konnte keine signifikante Altersabhängigkeit der arteriellen bzw. venösen Dilatation oder des AVDQ nachgewiesen werden. Die arterielle Dilatation ging nach 25,9±10,8 s in eine leichte Konstriktion von –2,7±1,4% über. Im Gegensatz dazu waren die Venen zum Zeitpunkt des individuellen Konstriktionsmaximums noch um 0,5±1,3% dilatiert (p<0,001).Schlussfolgerungen Die flickerlichtinduzierte Durchmesserreaktion retinaler Arterien und Venen unterscheidet sich bei Gesunden nicht in ihrem mittleren dilatativen Maximum, aber in Form und zeitlichem Verlauf des Abklingens der Dilatation.Unterstützung durch: BMBF 13N7999.Vortrag gehalten auf der 101. Jahrestagung der DOG, Berlin, September 2003.     

Acute Multifocal Placoid Pigment Epitheliopathy Associated with Cavernous Sinus Thrombosis

Acute multifocal placoid pigment epitheliopathy (AMPPE) has been associated with disease of the central nervous system. In this case report, we discuss a patient presenting with AMPPE in the setting of a new central nervous system association: cavernous sinus thrombosis.     

Dual nonlinearities regulate contrast sensitivity in pattern discrimination tasks

Many current psychophysical models propose that visual processing in cortex is hierarchical, with nonlinearities sandwiched between linear stages of processing. In earlier publications, we proposed a model of this type to account for masking effects found with spatial frequency and orientation discriminations. Our model includes two nonlinear mechanisms that regulate contrast sensitivity in early cortical mechanisms. The first is a local within-pathway nonlinearity that accelerates at low contrasts but is compressive at high. The second is a pooled nonlinear gain control process that operates over a broad range of neurons with different tuning characteristics. Here, we test predictions of the model for spatial frequency discriminations. The model predicts that at low contrasts, adding a grating mask oriented parallel to test gratings will improve discrimination performance via operation of the within-pathway nonlinearity, analogous to the "dipper effect" found with contrast discriminations. Adding an orthogonally oriented mask is predicted to have no effect at low contrasts, where pooled gain control processes contribute little to performance. At high contrasts, the model predicts that performance will asymptote and become independent of contrast with either parallel or orthogonal masks. The results confirm model predictions.