角膜移植的研究进展

角膜移植是用透明、健康的供体角膜组织替换混浊病变的角膜组织,使患者复明或控制角膜病变,达到增进视力或治疗某些角膜疾病的眼科治疗方法.传统角膜移植分为穿透性角膜移植和板层角膜移植.近10a,深板层角膜移植和内皮细胞移植手术逐渐崛起.而目前,人工角膜移植手术的发展为不适合传统穿透性角膜移植手术的患者提供一种新的选择.本文综述了目前角膜移植领域手术技术的适应证、术后并发症等.     

生存质量评价在角膜移植手术前后的应用

角膜移植术是治疗角膜盲的主要方法,生存质量作为一种较全面体现新的健康观和医学模式的评价体系已引入眼科领域,能更全面地反映疾病对患者的影响,是传统视功能评价方法的有益补充.角膜疾病对患者生存质量可产生不同程度的影响,而角膜移植术对于不同患者的生存质量具有不同的改善作用.本文主要对生存质量评价的相关知识以及生存质量测定在角膜疾病和角膜移植术后的应用情况进行综述.     

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。     

角膜移植手术新进展

近10年来,角膜移植手术无论在手术理念、手术设备和器械方面都得到较大的发展。在过去的半个世纪．穿透性角膜移植一直处于治疗角膜盲患者的主导地位,近年来成分角膜移植得到迅速发展,已逐渐代替穿透性角膜移植,成为角膜移植的主流。板层角膜移植可以取代穿透性角膜移植治疗位于角膜深基质层以上的病变,角膜内皮移植则用于治疗发生于角膜内皮的病变。此外,飞秒激光技术的发展使其在角膜移植手术中得到较好的应用,可以替代传统的角膜环钻,辅助角膜移植手术开展。总之．角膜移植手术理念的改进和技术的进步,减少了角膜移植并发症,更加节省角膜供体,并能够获得更快的视力恢复和更好的视觉效果。     

角膜移植手术相关白内障手术治疗的研究进展

角膜移植术后白内障是常见的并发症,与常规白内障手术相比,角膜移植术后白内障手术具有较高的风险。通过在白内障手术前对角膜内皮细胞进行详细全面的评估,判断角膜移植术后进行白内障手术的安全性,在手术时应用先进的白内障手术设备及技术,选择合适的术式,以及术后进行长期的随诊,会让更多角膜移植术后并发白内障的患者获得更好的治疗,拥有更佳的生活视力。     

角膜内皮功能紊乱的易患因素

角膜内皮细胞密度是临床医师评估角膜内皮功能最常用的项目,但角膜内皮功能紊乱却没有得到相应的重视.近年来对各种眼部原发疾病、角膜移植术后等所致角膜内皮功能紊乱的临床数据有了更翔实的更新.眼部原发病中,各种类型的青光眼对角膜内皮的影响不尽相同,其中急性闭角型青光眼对角膜的损伤程度较慢性闭角型青光眼及开角型青光眼严重,青光眼不同的治疗方案对内皮的影响也各有特点.葡萄膜炎患者角膜内皮损伤的严重程度与炎症复发频数、炎症反应程度及病程密切相关.剥脱综合征患者前房含氧量低、细胞外纤维物质在眼前段的堆积、细胞发生纤维化改变等因素均可降低角膜内皮的功能,导致剥脱综合征患者角膜内皮细胞对损伤的耐受性差.对于角膜移植术后的患者,角膜移植排斥反应、手术方式、原发病、继发性晚期角膜内皮衰竭是角膜移植术后患者角膜内皮功能紊乱的重要因素.糖尿病是引起角膜内皮细胞储备能力下降的常见的全身性疾病,糖尿病患者细胞膜Na+/K+-ATP酶泵的功能降低、大量的晚期糖基化终产物的生成、代谢应激作用增强等因素均可降低角膜内皮创伤修复及愈合能力.本文就角膜内皮功能紊乱的易患因素进行综述,以帮助临床医师理解及重视该因素在内眼手术前的评估.     

新型辅助技术在角膜病相关性白内障手术中的应用价值

角膜病相关性白内障,即在角膜病的基础上又发生了晶状体混浊,严重损害视觉质量。为使部分患者免于角膜移植术,恢复部分视功能。全面准确评估角膜混浊对视功能的影响对判定单纯行白内障手术具有重要意义。受限于角膜混浊遮挡,白内障手术操作具有高难度及挑战性。故开发使用新型辅助技术,如囊膜染色技术、辅助照明技术、瞳孔扩张技术、飞秒激光辅助技术等,可规避角膜混浊带来的可视性受限、通光量下降等问题,助力白内障手术顺利进行。本文就角膜病相关性白内障手术辅助技术的有关进展进行综述,望能指导临床应用。     

角膜前弹力层移植术治疗圆锥角膜研究现状

角膜前弹力层分隔角膜上皮和前基质。可能与保持角膜的透明性和稳定角膜形态与生物力学有密切的联系。圆锥角膜出现前弹力层的断裂和基质胶原填充等组织病理表现。角膜前弹力层移植术是一种新型的角膜移植术, 适用于角膜接触镜治疗效果不佳, 且不适合紫外线角膜交联和角膜基质环植入治疗的进展性重度圆锥角膜患者。手术使用完整眼球或前板层角膜植片作为供体来源, 用基质床或基质袋法将植片植入患眼的角膜基质层。手术并发症包括术中角膜穿孔及术后急性角膜水肿。手术后5年总体成功率84%, 术后患者视觉质量、角膜形态有明显改善, 同时可有效预防疾病进展, 推迟或避免进行穿透角膜移植术或深板层角膜移植术。该手术具有创伤小、术中及术后并发症少的优势, 但其手术技术精度高、难度大。本文就角膜前弹力层移植术的理论基础、最新的手术技术及预后和转归情况进行综述。     

准分子激光在板层角膜移植术中的应用

传统的板层角膜移植术后视力恢复不良主要是因为植片、植床剖面粗糙 ,界面间瘢痕形成影响视力。近年来兴起的准分子激光可精确地切削组织 ,切面光滑 ,用准分子激光制作植床、植片将会大大提高界面光滑度 ,减少瘢痕形成 ,改善术后视力。本文就这方面的有关问题作一综述。一、板层角膜移植的主要问题角膜病是最常见的致盲性眼病之一 ,角膜移植是目前公认的治疗这类疾病最有效的方法 ,包括部分穿透性角膜移植术和板层角膜移植术。板层角膜移植术是用相应厚度的健康板层角膜取代病变板层角膜的手术 ,可治疗中浅层角膜白斑、各种实质浅层的角膜营…     

圆锥角膜患者角膜移植术后视功能和生活质量改善的评价

角膜移植是角膜盲患者复明的惟一手段,传统评价角膜移植手术效果的指标主要为视力.然而随着医学模式从生物医学向生理、心理及社会医学的转变和角膜移植的特殊性,人们逐渐认识到单纯的视力检查不能全面反映角膜移植手术对患者生理、心理及社会活动的影响.     

组织工程角膜研究和应用进展

中国角膜供体材料的严重缺乏导致众多的角膜盲患者不能通过角膜移植来复明仍是临床棘手的问题。近年来,细胞生物学、组织工程学和材料学的发展为替代人角膜材料开辟了更广阔的前景;而且以深板层移植和内皮移植为代表的成分板层移植的推陈出新从临床技术上有力地推动了组织工程角膜的研发。现就脱细胞角膜基质板层材料、上皮细胞和内皮细胞组织工程的基础研究和临床应用进展进行述评。     

适宜中国国情的角膜移植技术的挑战和创新

角膜盲是我国仅次于白内障的致盲性疾病,角膜供体材料匮乏造成角膜盲患者绝对数量仍在逐年上升。与欧美发达国家不同,严重的感染性角膜炎、热烧伤、化学伤和各种眼内手术引起的大泡性角膜病仍然是我国角膜移植的主要适应证。我国角膜盲的防盲面临着患者病情重、依从性差、可支付能力低和角膜供体材料严重缺乏的多重挑战。近年来,我国的角膜专科医师根据特殊的国情,发展和创新了一系列深板层移植、内皮移植、人工角膜移植和组织工程角膜异种移植的新技术,从技术层面显著提高了供体角膜材料的利用率,降低了高危移植的排斥反应。然而,由于角膜供体材料极其缺乏的瓶颈依旧,能掌握当代角膜移植新技术的角膜专科医师数量稀少,目前推动角膜捐献的立法工作和深入组织工程异种角膜材料学研究、加强国际间眼库合作迫在眉睫,适宜国情的角膜移植技术的创新和推广工作仍然任重而道远。     

Outcome of penetrating keratoplasty in patients with bilateral corneal blindness

PURPOSE: To evaluate the outcome of penetrating keratoplasty in patients with bilateral corneal blindness. METHODS: Bilaterally blind patients who had undergone optical penetrating keratoplasty (PK) were evaluated on optical and refractive parameters and presence of complications if any. The results at 3 months, 6 months, and 1 year were compared with age-matched and indication-matched unilaterally blind controls. RESULTS: The most common indication for surgery in both the groups was the presence of a corneoiridic scar. Best corrected visual acuity of > or =6/18 was seen in five (16.66%) patients in the study group and in 11 (36.66%) patients in the control group (P = 0.14). In all, 15 (50%) grafts in the study group and six (20%) in the control group failed (P = 0.03). The most common cause of failure was graft infection (40%) in the study group and post-PK glaucoma (20%) in the control group. The percentage of graft rejection as a cause of graft failure was the same in both the groups. A composite socioeconomic status scale based on family literacy and income suggested that 70% of the cases in the study group and 30% in the control group belonged to the low socioeconomic group (P = 0.004). CONCLUSION: The outcome of optical penetrating keratoplasty in patients with bilaterally blinding corneal disease is poorer than those who are unilaterally blind. Low socioeconomic status may be a contributing factor for the poor outcome.     

Surgical strategies to improve visual outcomes in corneal transplantation

The recent years have brought about a sea change in the field of corneal transplantation with penetrating keratoplasty being phased to newer lamellar keratoplasty techniques for a variety of corneal pathology. Improved and innovative surgical techniques have allowed selective replacement of diseased host corneal layers with pre-prepared healthy donor corneal lamellae for anterior corneal disorders such as keratoconus and posterior corneal disorders such as Fuch''s corneal endothelial dystrophy. The results of lamellar techniques are encouraging, with rapid visual rehabilitation and vastly reduced risk of immune-mediated transplant rejection. The techniques of deep anterior lamellar keratoplasty and Descemet''s stripping endothelial keratoplasty (DSAEK) continue to evolve with advent of femtosecond lasers and newer concepts such as pre-conditioned donor corneas for Microthin DSAEK and Descemet''s membrane keratoplasty. This review describes the current developments in lamellar keratoplasty, including the futuristic approach using cell therapy to restore vision in corneal blindness.     

The value of corneal transplantation in reducing blindness

PURPOSE: To analyse the role of keratoplasty in reducing world blindness due to corneal diseases. METHODS: Review of published literature. We collected and analysed articles published in the English language literature related to the prevalence and causes of blindness in different parts of the world, causes of corneal blindness, and outcome of corneal transplantation for various corneal diseases. RESULTS: A total of 80% of the world's blind live in developing countries. Retinal diseases are the most important causes of blindness (40-54%) in established economy nations while cataract (44-60%) and corneal diseases (8-25%) are the most common causes of blindness in countries with less developed economies. Keratitis during childhood, trauma, and keratitis during adulthood resulting in a vascularized corneal scar and adherent leucoma are the most frequent causes of corneal blindness in developing countries. Corneal diseases are responsible for 20% of childhood blindness. Nearly 80% of all corneal blindness is avoidable. The outcome of keratoplasty for vascularized corneal scar and adherent leucoma is unsatisfactory, necessitating repeat surgery in a high proportion of these cases. Other barriers for keratoplasty in these nations are suboptimal eye banking, lack of trained human resources, and infrastructure. CONCLUSIONS: Since the developing world carries most of the load of corneal blindness and the major causes of corneal blindness are corneal scar and active keratitis, development of corneal transplantation services need a comprehensive approach encompassing medical standards in eye banking, training of cornea specialists and eye banking personnel and exposure of ophthalmologists to care of corneal transplants for better follow-up care. However, concerted efforts should be made to develop and implement prevention strategies since most corneal blindness is preventable.     

Bevacizumab在眼表疾病中的应用

眼表疾病是临床常见的致盲眼病,特别是角膜新生血管性眼病因其发病机制非常复杂,治疗棘手而成为眼科新研究领域一大难点和热点。Bevacizumab给药靶向阻断血管内皮生长因子及其受体,有效抑制新生血管生长,其抗淋巴血管性、抗纤维性有望成为角膜移植术后免疫排斥反应、LASIK术前常规及预防用药,现综述如下。     

Current concepts and techniques in keratoprosthesis

PURPOSE OF REVIEW: Diseases affecting the cornea are a major cause of blindness worldwide, second only to cataract in overall importance, with an estimated 10 to 15 million affected people. Although keratoplasty is by far the most successful transplantation surgery, the outcomes in high-risk adult patients, including those with ocular surface diseases and multiple graft rejections, and in pediatric patients with congenital corneal opacities are disappointing. RECENT DEVELOPMENTS: Regrettably, no significant clinical developments have been achieved in the field of corneal transplantation since the introduction of steroids for graft rejection. Furthermore, obtaining donor corneal tissues and eye banking, particularly in the developing countries where corneal blindness is most prevalent, are problematic. Although the postoperative complications may be severe and limit the use of currently available devices, keratoprosthesis--artificial corneal implantation--has a role in the management of corneal blindness in carefully selected patients with complex ocular diseases who are at high risk for graft failure. SUMMARY: This article reviews the recent ophthalmic literature published on the current concepts and techniques of keratoprosthesis surgery.     

HLA B27 scheint Transplantatversagen nach Hornhautverpflanzung bei herpetischen Hornhautnarben zu fördern

BACKGROUND: Herpes simplex virus (HSV) is the leading cause of infectious corneal blindness in the developed world. Eighty percent of the general population develop asymptomatic viral latency in the trigeminal ganglion following orofacial inoculation, but only 0.2% of all such orofacial inoculations are followed by recurrent corneal reactivation. Recurrences still threaten graft survival following penetrating keratoplasty, so that advance identification of patients at increased risk would be helpful in aftercare following penetrating keratoplasty. The HLA B27 phenotype is associated with increased susceptibility to genital HSV. However, no such association has been reported for herpetic eye disease. METHODS: The HLA phenotypes of 129 patients who underwent penetrating keratoplasties for herpetic corneal scars were available for retrospective analysis. Four of these patients were positive for HLA-B27. The 125 HLA-B27-negative patients served as controls. The mean follow-up was 2.2 years. We compared the frequencies of herpetic recurrence and graft failure in the two groups using the Kaplan-Meier method and applied log-rank statistics. RESULTS: After the average period of follow-up, 75% (three patients) of the HLA B27-positive patients experienced either graft failure or at least one reversible recurrence of the herpetic eye disease, as against only 25% of controls. This difference was highly statistically significant (p<0.01). CONCLUSION: This retrospective analysis suggests that the HLA B27 phenotype promotes recurrence of herpetic eye disease following penetrating keratoplasty. HLA B27-positive patients should be closely monitored, and the indications for prophylactic antiviral therapy should be viewed liberally in this group.