正确选择角膜内皮移植的适应证

角膜内皮移植具有许多独特的优点,有望取代穿透性角膜移植成为治疗角膜内皮失代偿的首选术式.然而,内皮移植也存在术后内皮细胞密度偏低的缺陷,而且,我国的大泡性角膜病变主要见于白内障等眼内手术造成的角膜内皮损伤,病情严重且伴多种眼内异常,使角膜内皮移植面临较大的困难,术后内皮细胞密度下降更明显.根据患者的病情特点,选择合适的术式和适应证是保证手术成功的关键.采用一些改良技术也能减轻内皮细胞的损伤,提高手术成功率.     

角膜内皮移植术

角膜内皮移植是一种新的治疗角膜内皮病变的手术方法,主要是采用健康的角膜内皮片替代病变内皮层.该方法因为几乎不改变患者的角膜曲率和屈光状态,损伤小,视力恢复快,近年来在临床上逐渐被推广应用,取得较好愈后效果.该方法是角膜移植手术不断精细化和向屈光性手术转化的具体体现.角膜内皮移植术后良好的屈光效果和可能的低排斥率,使其有望成为角膜内皮病变治疗的重要方式.但是,目前内皮移植手术仍然需要完善,改进植入方法以减少脱片率和内皮细胞损失率,利用飞秒激光等进一步提高屈光效果,以及观察术后免疫排斥率是今后眼科学者的研究重点.     

无内皮移植的后弹力层剥离手术促进中央角膜内皮再生的研究进展

角膜内皮功能损害传统上被认为是不可逆的,角膜内皮移植几乎是目前唯一的治疗方式。然而,近来出现的仅剥离Descemet膜而无内皮移植的手术(DWEK)可使Fuchs角膜内皮营养不良患者中央角膜内皮细胞再生,而局部Rho相关激酶抑制剂可以促进其疗效。     

不撕除后弹力层的角膜内皮移植治疗大泡性角膜病变一例

角膜内皮移植已逐渐用于治疗大泡性角膜病变，并取得了较好的临床效果。目前，被广泛接受的手术方式是撕除病变的后弹力层和内皮，然后植入带有小于100μm厚度的供体角膜内皮片，通过前房注气使其贴附于后表面。这种方式被称为后弹力层撕除自动内皮移植（Descemet stripping automated endothelial keratoplasty，DSAEK）。尽管这种手术方式对患者眼部角膜损伤小，术后恢复快，但是很多情况下除了做常规角巩膜切口供内皮植入外，还要在角膜做切口以便撕除后弹力层。[第一段]     

角膜内皮移植技术的发展

角膜内皮移植术已成为治疗各种原因引起的角膜内皮功能失代偿的首选术式.角膜内皮移植手术与穿透性角膜移植手术相比,其较好地保持了眼前节的生物学完整性,术后视力恢复更快、更好,大大降低术后并发症等.本文就角膜内皮移植技术的发展过程,主要手术方式,手术的优缺点及术后并发症等进行综述,以期为临床应用提供参考.     

组织工程角膜内皮移植研究进展

由于角膜供体材料严重短缺, 穿透角膜移植术及角膜内皮移植术的临床广泛开展受到严重制约, 其根本原因在于健康角膜内皮的增生能力有限。随着组织工程技术和细胞工程技术不断发展, 组织工程角膜研究已取得一定进展, 应用组织工程技术体外培养高密度、具备健康内皮功能的角膜内皮细胞进行移植是当前研究的热点。组织工程角膜内皮技术研发的关键在于种子细胞、载体材料和移植方式的选择。目前, 国内外大量研究的种子细胞来源包括人角膜内皮细胞、干细胞、血管内皮细胞及人羊膜上皮细胞等。常见的载体材料包括羊膜、脱细胞角膜基质、后弹力层、晶状体前囊膜等。体外培养的细胞采用穿透角膜移植术、角膜内皮移植术或前房注射细胞的方式进行移植。本文从角膜内皮种子细胞来源、移植载体选择以及角膜内皮移植方法等方面就组织工程角膜内皮移植研究进展进行综述, 总结目前研究面临的问题并展望其前景。     

角膜后弹力膜内皮移植术研究进展

角膜后弹力膜内皮移植术由于具有相对较低的移植排斥率以及较好的视力预后等优势,目前已成为部分发达国家治疗角膜内皮失代偿的主流手术方式,但限于手术难度较高,学习曲线较长,中国人前房偏浅,加之国内角膜内皮病变往往合并有其他较复杂的眼部疾病,目前国内尚未普遍开展这一手术。本文就角膜后弹力膜内皮移植术的手术适应证、供体植片制备(...     

组织工程角膜内皮的体外构建及在猕猴角膜移植中的应用

目的体外构建出形态结构功能正常的组织工程人角膜内皮（TE-HCE）,并以猕猴动物模型验证其维持角膜透明的作用。方法实验研究。以非转染人角膜内皮单克隆细胞株细胞（mcHCE细胞）为种子细胞,以去上皮层修饰羊膜（mdAM）为载体支架体外构建出TE-HCE,对其透明度、形态、细胞密度、组织学结构、超微结构、功能蛋白的荧光表达进行检测;采用穿透性角膜移植手术（PKP）对猕猴右眼分别移植TE-HCE（3眼,TE-HCE组）和mdAM（3眼,mdAM组）,未移植的左眼作为正常对照眼（6眼,对照组）,利用裂隙灯显微镜、角膜内皮镜、角膜测厚仪和眼压计对术后动物的角膜透明度、角膜内皮细胞密度（ECD）、中央角膜厚度（CCT）和眼压（IOP）进行在体检测,并利用荧光显微镜检测移植眼角膜内皮细胞的CM-DiI标记。数据处理均采用单因素方差分析。结果体外构建的TE-HCE透明度高,具有与活体角膜内皮近似的形态结构,单层细胞密度高达（3 602±45）个/mm2,细胞连接蛋白和膜运输蛋白呈阳性表达;术后跟踪观测结果显示,TE-HCE移植眼的角膜没有出现明显的炎症和免疫排斥反应,角膜维持透明,虽然出现了轻度角膜水肿,但随着时间的推移CCT逐渐下降,术后181 d时单层细胞密度为（2 796±157）个/mm2;而mdAM移植眼的角膜则出现了明显的炎症反应,长入了新生血管,角膜持续混浊与水肿,厚度没有明显的下降趋势;各组间IOP的变化无明显差异。CM-DiI荧光检测结果显示TE-HCE移植眼的角膜内皮移植区的细胞均带有CM-DiI标记（来自于移植的TE-HCE）。结论体外构建的高密度TE-HCE具有正常的形态结构,且功能蛋白表达正常,移植后能使猕猴角膜逐渐恢复透明度和厚度,表明TE-HCE在体内可重建出功能正常的角膜内皮,有望用于角膜内皮异常疾病的临床治疗。     

迎接角膜移植手术发展的新阶段

穿透性角膜移植已经不是角膜手术的唯一标准和手段,成分移植的理念带来了手术方式的新突破,由此涌现出的深板层移植、内皮移植等显著降低了术后的排斥反应等并发症,提高了视觉质量和供体角膜的利用度。飞秒激光的应用将角膜移植手术带入了屈光手术时代。角膜胶原交联技术的出现,丰富了医生的治疗手段,使圆锥角膜等角膜疾病大幅度摆脱了对角膜移植手术的依赖。这一系列进步使角膜移植手术进入了精准医疗的范畴。     

角膜内皮移植手术的进展

随着对角膜生理和光学作用认识的深入,以及眼科新技术,新设备的不断涌现,角膜内皮移植手术取得了飞速的发展.从DLEK到DSEK,DSAEK再到后来的DMEK,手术操作日趋简便,切口逐渐缩小,更多的保留了正常角膜组织的形态和功能,减少了术后并发症的发生,加快了患者视力恢复速度.随着手术操作的不断改进,角膜内皮移植在临床应用中取得了良好的疗效并显示出诸多优势.目前,角膜内皮移植正在取代传统的穿透性角膜移植,成为治疗角膜内皮疾病的重要术式,使角膜移植由治疗性手术逐渐向屈光性手术过渡.     

Descemet-stripping automated endothelial keratoplasty: a successful alternative to repeat penetrating keratoplasty

Background: Although Descemet‐stripping automated endothelial keratoplasty has replaced penetrating keratoplasty for primary treatment of endothelial disorders, many patients have already undergone penetrating keratoplasty. It is unclear when repeat penetrating keratoplasty is necessary or when endothelial keratoplasty may restore clarity to a failed graft. Design: Retrospective case series of patients undergoing Descemet‐stripping automated endothelial keratoplasty after penetrating keratoplasty by three surgeons at an academic tertiary care centre. Participants: Eight patients with Descemet‐stripping automated endothelial keratoplasty after penetrating keratoplasty from 2006 to 2009. Methods: Microkeratome‐prepared Descemet‐stripping automated endothelial keratoplasty donor tissue was used. In seven cases, the penetrating keratoplasty bed was neither stripped nor scraped, and in one, scraping only was performed. Main Outcome Measures: Preoperative and 6‐month postoperative best‐corrected visual acuities in logMAR (logarithm of the minimum angle of resolution). Results: The average pre‐Descemet‐stripping automated endothelial keratoplasty best‐corrected visual acuity was 1.375, and the average best‐corrected visual acuity 6 months postoperatively was logMAR 1.0, a 2.5‐fold improvement in the minimum angle of resolution (P = 0.22). Seven of the eight patients showed an improvement in best‐corrected visual acuity, and one patient had failure of Descemet‐stripping automated endothelial keratoplasty and required penetrating keratoplasty. Five had a postoperative event: one had a gap that resolved spontaneously, three required rebubblings (injections of air only without otherwise repositioning the graft), and one experienced graft failure. Conclusions: Descemet‐stripping automated endothelial keratoplasty can successfully rescue a prior penetrating keratoplasty, even with a fairly high detachment rate. Given these favourable visual outcomes, further study of this promising strategy is justified.     

Descemet's stripping with automated endothelial keratoplasty (DSAEK)

BACKGROUND: Although penetrating keratoplasty remains the gold standard for surgically treating corneal endothelial pathologies, tremendous progress has been made in recent years to improve the technology of (posterior) lamellar keratoplasty. METHODS: Literature review from PubMed and own data. RESULTS: Posterior lamellar keratoplasty using a microkeratome (Descemet's stripping with automated endothelial keratoplasty, or DSAEK) is a reliable surgical technique for Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation is faster with lamellar keratoplasty than penetrating keratoplasty. CONCLUSION: Posterior lamellar keratoplasty techniques such as DSAEK will become an important surgical treatment option for corneal endothelial pathologies.     

Endothelial keratoplasty: a revolution in evolution

Endothelial keratoplasty (EK) is continually evolving both in surgical technique and clinical outcomes. Descemet's stripping endothelial keratoplasty (DSEK) has replaced penetrating keratoplasty (PK) as the treatment of choice for corneal endothelial dysfunction. It is safe and predictable and offers early visual rehabilitation. Newer iterations include Descemet's membrane endothelial keratoplasty, Descemet's membrane automated endothelial keratoplasty, and other hybrid techniques. Early data on these newer EK techniques suggests that they provide significantly better visual outcomes compared to DSEK. Initial 5-year survival data indicates that EK is at least comparable to PK, and more widespread survival data is anticipated. Further work is needed to simultaneously optimize visual outcomes, refractive predictability, and endothelial cell survival, as well as surgical techniques of donor preparation and insertion.     

Endothelial keratoplasty: improvement of vision after healthy donor tissue exchange

OBJECTIVE: To report 3 cases of graft exchange by using a microkeratome-prepared donor tissue in place of a manually prepared donor tissue for inadequate postoperative visual acuity after deep lamellar endothelial keratoplasty and to discuss possible etiologies. METHODS: Prospective, observational case series. The patients were 3 consecutive patients who underwent endothelial graft replacement for unsatisfactory vision after initial deep lamellar endothelial keratoplasty. This is a review of clinical findings in 3 cases of endothelial keratoplasty that underwent graft exchange for unacceptable vision after deep lamellar endothelial keratoplasty. RESULTS: Two patients benefited from graft exchange by using a microkeratome-prepared donor in place of a manually prepared donor with improvement in best spectacle-corrected visual acuity and 1 did not because of recipient bed irregularities. Vision improved in this patient with penetrating keratoplasty. CONCLUSIONS: Endothelial keratoplasty results in rapid visual recovery and excellent vision. However, fewer eyes achieve 20/20 vision than with full-thickness penetrating keratoplasty. This report shows that some patients with suboptimal vision after endothelial keratoplasty felt to be caused by interface optical problems may benefit from either graft exchange or penetrating keratoplasty.     

Endothelial cell loss after autologous rotational keratoplasty

Purpose To investigate whether it may be possible to ascertain the influence of immunological factors on chronic endothelial cell loss by comparing chronic endothelial cell loss after autologous rotational penetrating keratoplasty and after homologous penetrating keratoplasty.Methods For six patients who had undergone autologous rotational penetrating keratoplasty the relative annual loss of endothelial cells was calculated by means of an exponential regression analysis. The findings were compared with those in a homogeneous historical control group (53 patients undergoing homologous penetrating keratoplasty for keratoconus).Results After autologous rotational keratoplasty relative annual loss of endothelial cells was 1.1%±2.6% (mean ± standard deviation). Relative annual loss of endothelial cells in the control-group was 16.7%±20.8%.Conclusions The results of the study lead to the assumption that immunological influences might be the main cause for chronic endothelial cell loss after homologous penetrating keratoplasty.Presented as a lecture during the annual convention of the German Ophthalmological Society (DOG) in Berlin, 25–28 September 2003     

Posteriore lamelläre Keratoplastik (DSAEK)

Penetrating keratoplasty has been the gold standard for the surgical treatment of corneal endothelial pathologies, but tremendous progress has been made in recent years in improving the technology of posterior lamellar keratoplasty techniques such as Descemet’s stripping automated endothelial keratoplasty (DSAEK). This progress is shown by a literature review using PubMed sources and our own clinical and experimental data. Posterior lamellar keratoplasty using a microkeratome is a reliable surgical technique for Fuchs’ endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation is faster with lamellar compared with penetrating keratoplasty, but final visual acuity seems to be a bit reduced. Posterior lamellar keratoplasty techniques such as DSAEK may replace penetrating keratoplasty as the gold standard for treating a large proportion of corneal endothelial pathologies.     

Descemet's stripping with endothelial keratoplasty in iridocorneal endothelial syndrome.

An interventional case is described to report on the clinical outcome of Descemet's stripping automated endothelial keratoplasty performed for iridocorneal endothelial syndrome. A Descemet's stripping automated endothelial keratoplasty was performed in the eye of a 53-year-old woman with decompensated cornea secondary to iridocorneal endothelial syndrome. The transplant and the angle were evaluated with optical coherence tomography. Within 10 months postoperatively, the graft was clear and best-corrected visual acuity improved from 20/400 to 20/30. Descemet's stripping automated endothelial keratoplasty appears to be an effective measure to treat corneal decompensation, improve vision, and facilitate the examination of the optic disc and retina in patients with iridocorneal endothelial syndrome.     

Immune cells in the anterior chamber of patients with immune reactions after penetrating keratoplasty.

PURPOSE: Lymphocytes, monocytes, and macrophages are the predominating immune cells in graft rejection after keratoplasty in animal models. This study focuses on the isolation of immune cells from the anterior chamber of patients with slight, moderate, and severe endothelial immune reactions after penetrating keratoplasty. METHODS: Anterior chamber puncture was performed in five patients with cataract without inflammation and without penetrating keratoplasty (C1), in three patients undergoing penetrating keratoplasty without immune reactions (C2), in four patients undergoing penetrating keratoplasty after complete resolution of endothelial immune reactions (C3), in seven patients undergoing penetrating keratoplasty with slight endothelial immune reactions (IMI), in 10 patients undergoing penetrating keratoplasty with moderate endothelial immune reactions (IM2), and in eight patients undergoing penetrating keratoplasty with severe endothelial immune reactions (IM3). In each patient, approximately 0.1 mL of aqueous humor was examined. Cells in suspension were directly centrifuged on glass slides using a Cytospin centrifuge, stained, and evaluated under the light microscope. RESULTS: Groups C1, C2, and C3 did not contain cells. Immune cells were identified in three of seven patients in IM1, in eight of 10 patients in IM2, and in eight of eight patients in IM3. Predominating cells were macrophages and monocytes followed by lymphocytes. Regarding all patients in IMI, IM2, and IM3, a statistically significant correlation between detected cells and patient age, period between penetrating keratoplasty and anterior chamber puncture, or period between first symptoms and anterior chamber puncture could not be revealed. Granulocytes were found statistically significantly less often in patients with high-risk indications, in patients with a history of immune reactions and under immunosuppression. Lymphocytes were found statistically significantly less often in patients with a history of immune reactions. CONCLUSIONS: The probability to isolate immune cells from the anterior chamber of patients undergoing penetrating keratoplasty correlates with the severity of the endothelial immune reactions. This study is a first step to evaluate how detailed immunologic findings from animal keratoplasty models fit to clinical reality in patients undergoing keratoplasty. In the next step, cells found in the aqueous humor of patients with endothelial immune reactions should be further characterized directly (determination of molecules on the surface of the cells) or indirectly (determination of cytokine levels in the aqueous humor).     

DMEK: posteriore lamelläre Keratoplastiktechnik

Background

Penetrating keratoplasty is at present the gold standard for surgical treatment of corneal endothelial pathologies but tremendous progress has been made in recent years in improving the technology of (posterior) lamellar keratoplasty techniques, such as Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods

A review of the literature was carried out using PUBMED and own clinical and experimental data.

Results

Isolated transplantation of Descemet’s membrane with endothelial cells after stripping the host Descemet’s membrane is a new surgical technique for Fuchs endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation seems to be faster and better with DMEK compared to penetrating keratoplasty.

Conclusion

Posterior lamellar keratoplasty techniques such as DMEK will replace penetrating keratoplasty as the gold standard for treatment of a large segment of corneal endothelial pathologies.