Boston type I keratoprosthesis

Successful corneal solid tissue transplantation,beginning with penetrating keratoplasty(PKP),and evolving to include contemporary lamellar and endothelial keratoplasty,has been a tremendous advancement in the struggle to combat corneal blindness.However,there remain patients with high-risk features predictive of transplant failure,for whom donor keratoplasty is not a viable option.Prosthetic corneas have therefore been developed in order to meet the needs of these patients.The Boston type I keratoprosthesis(BKPro)is the most widely used prosthetic cornea in the treatment of corneal blindness.In the years since the BKPro’s introduction,refinement of surgical technique and clinical management as well as improvements in prosthetic design have contributed to promising patient outcomes,particularly in the short term.As such,patients with keratoprosthesis implants continue to grow in number,and the indications for the BKPro have commensurately increased.However,risks of permanently blinding complications after implantation persist over all stages of follow-up.For the foreseeable future,the success of keratoprosthesis(KPro)implantation will continue to depend on refined patient selection,preoperative optimization,and incisive postoperative management.Here we explore indications,surgical technique and postoperative outcomes as well as several core tenants in the management of BKPro patients:limiting glaucomatous progression,controlling inflammation,and optimizing the ocular surface.The exquisite sensitivity of the BKPro-implanted eye to perturbations in any one of these areas showcases the intimate relationship between the prosthetic device and its surrounding environment.

Experimental study on the biocompatibility of keratoprosthesis with improved titanium implant

AIM：To investigate whether hydroxyapatite（HAp）coating can improve keratoprosthesis（KPro）implant biointegration,ultimately to decrease the risk of implantassociated complications.METHODS：The modified titanium implant was designed and prepared for artificial cornea.The titanium implant was treated with sandblasting and hydroxyapatite coating by acid-base two-step method.Surface was analyzed by scanning electron microscopy（SEM）,KPro implants coated with HAp and KPro implant sandblasted were implanted in rabbits.Tissue adhesion to the implant was assessed and compared to an unmodified implant by histopathology（HE）,transmission electron microscopy（TEM）and SEM.RESULTS：SEM demonstrated successful deposition of HAp on titanium implant sandblasted（HA/SB-Ti）.The hydroxyapatite coatings caused enhancement of keratocyte proliferation compared with unmodified implant surfaces.HAp coating significantly increased adhesion forces.HAp coating of implants reduced the inflammatory response around the KPro implants in vivo.CONCLUSION：HAp-coated surfaces for use in titanium KPro implant greatly enhanced adherence of the titanium KPro implant in the rabbit cornea.

Forty-five years of keratoprosthesis study and application at the Filatov Institute: a retrospective analysis of 1060 cases

AIM: To present results of the keratoprosthesis method used at The Filatov Institute of Eye Diseases and Tissue Therapy. ·METHODS: A retrospective case series analysis was used to describe the development of new types of keratoprostheses and methods of implantation as well as different ways of leukoma strengthening. ·RESULTS: Keratoprosthesis was performed in 1 060 eyes of 1 040 patients with leukomas of different etiology: burns, 725 eyes (68.4% ); trauma, 120 eyes (11.3% ); keratitis and ocular pemphigoid, 108 eyes (10.2% ); and bullous keratopathy, 107 eyes (10.1% ). Visual acuity before keratoprosthesis consisted of light perception in 962 eyes (92% ), and 98 eyes (8% ) had minimal visual acuity (1/200-1/50). Both eyes were blind (visual acuity less than 1/200) in 955 patients (91.8% ). The period of blindness varied from 1 to 52 years. As a result of keratoprosthesis, visual acuity of ≥1/200 was restored in 1 023 of 1 060 eyes (96.5%). Visual acuity of 20/200-20/20 was achieved in 716 eyes (67.5%). At the last follow-up visit visual acuity of ≥1/200 was preserved in 806 eyes (76%), visual acuity of 20/200-20/20 was measured in 583 of 1 060 eyes (55%) and good keratoprosthesis fixation in the cornea was achieved in 986 of 1 060 eyes (93%). The minimal follow-up was 12 months (range, 12 months to 37 years, median 5 years). · CONCLUSION: Our techniques of keratoprosthesis effectively restore vision in patients with leukomas that cannot be treated by optical corneal grafting.

Implantation of Iakymenko keratoprosthesis in patients with severe ocular injury

AIM: To present the results of implantation of Iakymenko keratoprosthesis in five patients with vascularized corneal leukoma caused by severe ocular injury. METHODS: Iakymenko keratoprosthesis was implanted into 5 eyes of 5 patients: 4 patients were suffered from chemical burns and 1 patient from explosive injury. The preoperative visual acuity ranged from light perception to hand motion. The implantation surgery was composed of two-stage procedures. The follow-up period was from 9 months to 11 years. The outcome measures were visual acuity, retention, and complications of the keratoprosthesis. RESULTS: Vision improvements were achieved in most patients. All keratoprosthesis were retained within the follow-up period. Corneal melting occurred in one patient and fibrous closure in another patient, both of which were successfully treated. Retinal detachment occurred in one patient after surgery. CONCLUSION: Iakymenko keratoprosthesis seems to be a promising alternative for the patients with severe corneal injury, but further investigation is needed to evaluate the role of Iakymenko keratoprosthesis.

Osteo-odonto keratoprosthesis in Stevens-Johnson syndrome:a case report

·AIM:To report a successful osteo-odonto keratoprosthesis(OOKP) procedure in a case of end stage of corneal blindness due to Stevens-Johnson syndrome (SJS).·METHODS:An interventional case report.·RESULTS:We describe a 35-year-old Indian woman,a known case of SJS with bilateral dry eyes and corneal blindness (failed corneal graft with vascularised total corneal opacity in the right eye and non-healing corneal ulcer in the left eye).Vision was hand movement only in both eyes.The corneal ulcer healed with medical treatment resulting in vascularised total corneal opacity with no improvement in vision.OOKP was performed in the right eye and the vision was improved from hand movement to 6/6.The same vision was maintained in the right eye at the last follow-up 5 years after surgery.·CONCLUSION:OOKP provides good visual rehabilitation with long-term anatomically stable prosthesis in patients with end-stage of ocular surface disorders and corneal blindness secondary to SJS.·

A novel temporary keratoprosthesis technique for vitreoretinal surgery

AIM:To investigate the safety of vitreoretinal surgery when using a soft contact lens as a temporary keratoprosthesis(TKP)in patients with severe corneal opacifications.METHODS:Three patients with simultaneous corneal and vitreoretinal pathology were treated with a soft contact lens that was used as a TKP to facilitate vitreoretinal surgery.The soft contact lens was fixated with sutures onto the globe so that no leakage was possible.RESULTS:Vitreoretinal surgery with excellent fundus view was possible in all cases.The soft contact lens allowed safe central and peripheral vitrectomy.Surgery was successful in all cases.CONCLUSION:A soft contact lens properly fixated on the globe can successfully replace a TKP.This surgical procedure has several advantages like one size fits all,low costs,and easy access to the material.

Surgical Cooperation during Implantation of a Boston type-Ⅰ Keratoprosthesis

This study was designed to summarize the key points of surgical cooperation involving penetrating corneal transplantation combined with implantation of keratoprosthesis. Preoperative preparation and intraoperative procedures were fully implemented to ensure cooperation with the physicians,.to observe the the severity of the disease, and to guarantee the success of the surgery.

AB088.Quality of life and visual function in patients with Boston type I keratoprosthesis

Background:To determine patient-reported vision-related quality of life(VR-QoL)following Boston type I keratoprosthesis(BI-KPro)surgery and its association with postoperative best-corrected visual acuity(BCVA).Methods:Descriptive cross-sectional study.Consecutive consenting patients with BI-KPro were included.The French National Eye Institute Visual Function Questionnaire-25 administered at 51±18 months postoperatively measured VR-QoL.Clinical charts were reviewed for demographics,indications for BI-KPro,baseline and postoperative(at time of interview)BCVA.For patients operated unilaterally,stratification of VR-QoL scores based on BCVA in the non-operated eye was performed.Multivariate linear regression was carried out,using VR-QoL scores as dependent variables,and demographics and postoperative BCVA as covariates.For patients operated bilaterally,Spearman correlation between VR-QoL scores and BCVA was performed.P<0.05 indicated statistical significance.Results:Sixty-four patients,aged 59±14 years,52%male,with a follow-up of 54±19 months,were included.Postoperative BCVA increased from baseline in all operated eyes(P=0.000).In patients with unilateral BI-KPro(n=52),the VR-QoL overall score was 70.7±25.1.Scores on all questionnaire subscales were greater when BCVA in the non-operated eye was>20/200 compared to 20/200(P=0.000).BCVA in the non-operated eye was positively associated with all subscales(P<0.01)independently of age,sex,follow-up duration and postoperative BCVA in the operated eye.In patients with bilateral BI-KPro(n=12)the VR-QoL overall score was 63.0±18.7.BCVA in the best eye positively correlated with Near/Distance activities,and social functioning subscales(P<0.05).There was no significant difference between VR-QoL scores of patients operated unilaterally vs.bilaterally.Conclusions:We describe VR-QoL more than 4 years after BI-KPro surgery.Compared to data at 1 year previously reported,our results suggest that,as vision progressively deteriorates in the operated eye,patients increasingly rely on their non-operated eye.VR-QoL after bilateral BI-KPro is assessed for the first time,and appears comparable to that after unilateral surgery.Larger,prospective,long-term studies,with assessment at baseline,are warranted.

9.999K纯金的生物相容性及其与角膜生物愈合特性的研究

目的 :研究 9.999K纯金的生物相容性及其与角膜的生物愈合特性 ,寻找理想的人工角膜周边制作材料。方法 :将制作有 70～ 80个小孔、厚 0 .1mm、直径 8mm、曲率半径 7.8mm的弧形 9 999K纯金薄片植入兔角膜板层中 ,裂隙灯观察并照相 ,不同时间点取材进行光镜、扫描电镜以及透射电镜检查。结果 :最长观察 7个月无脱出 ,在组织中稳定、无析出、无包裹、对周围组织无毒性。角膜成纤维细胞能长入人工制作的小孔内并合成胶原 ;8眼出现植入物前角膜基质层钙质沉积。术后第 2、3周出现不同程度的角膜水肿与新生血管 ,10天左右自行消退。结论 :纯金具有良好的生物相容性 ,通过人工制作的小孔与角膜产生生物愈合 ;植入物一定程度地影响了角膜的内环境 ;增加小孔面积后 ,可增加其生物相容性。

经羟基磷灰石处理的纯钛表面有利于角膜成纤维细胞的粘附和增殖(英文)

目的:研究与纯钛相比,经羟基磷灰石表面改性处理的纯钛是否能增加兔角膜基质成纤维细胞在其表面的粘附和增殖。方法:利用生物活性的羟基磷灰石对纯钛进行表面改性。将第4代兔角膜基质成纤维细胞接种于羟基磷灰石表面改性的钛、纯钛及玻璃表面,24,48,72h后,使用丫啶橙染色的方法观察材料表面细胞的粘附和增殖情况,电镜观察材料表面的细胞形态。结果:各个时间点,羟基磷灰石表面改性的钛表面的细胞数都多于其他材料(P<0.05)。24h,羟基磷灰石表面改性的钛表面和玻璃表面的细胞扩展面积要大于纯钛表面。72h电镜观察发现羟基磷灰石表面改性的钛表面的细胞扩展面积最大,细胞张力丝最长。结论:与纯钛相比。

改良PHEMA-PMMA一体化人工角膜治疗兔角膜碱烧伤的实验研究

目的评价改良聚羟乙基丙烯酸甲酯（PHEMA）-聚甲基丙烯酸甲酯（PMMA）一体化人工角膜时兔角膜碱烧伤的治疗效果。方法通过两阶段化学聚合结合车床机械切削合成改良的一体化人工角膜。将PHEMA海绵边裙材料植入10只正常兔角膜板层间，另10只碱烧伤兔眼角膜囊袋内1期植入一体化PHEMA—PMMA人工角膜，术后用组织病理、免疫组织化学和电镜检查观察海绵边裙与角膜组织的生物学愈合情况。术后2个月行II期手术．术后随访观察3～6个月。结果接受板层间植入术的10只兔角膜未见任何并发症。术后2周成纤维细胞长入PHEMA海绵，术后2～3个月多量细胞长入伴有新生血管；海绵孔隙中生长细胞和角膜基质细胞波形蛋白（Vim）免疫反应阳性；电镜下，细胞在海绵材料间隙中生长状态良好，并分泌胶原和细胞外基质。接受人工角膜移植术的10只碱烧伤兔眼中，1眼1期术中角膜穿孔而被排除，另9眼Ⅱ期术后，3眼2周内人工角膜镜柱偏位，6眼观察期间人工角膜在位。结论PHEMA海绵能够与角膜组织达到良好的生物学愈合；人工角膜的片型和整体强度有待进一步改良。

羟基磷灰石人工角膜支架生物相容性的实验研究

目的探讨天然珊瑚羟基磷灰石（ＨＡ）及仿ＨＡ生物陶瓷与角膜的生物相容性及愈合特性，以评价其作为人工角膜支架材料的可行性。方法分别将天然珊瑚ＨＡ支架与相同规格的仿ＨＡ生物陶瓷支架植入碱烧伤后兔角膜板层，于不同时间裂隙灯观察并进行组织病理学检查。结果天然珊瑚ＨＡ组：６例植入物，均获得了良好的稳定性及安全性，观察期最长已达１７个月，组织病理学检查亦证实其与角膜组织具有良好的生物相容性且不影响角膜组织的营养和代谢。仿ＨＡ生物陶瓷组：６例植入物在２个月内全部脱出，前板层角膜溶解、坏死。结论天然珊瑚ＨＡ与角膜组织具有良好的生物相容性，能与受体角膜生物愈合，可用作人工角膜支架。

人工角膜的研究进展

本文较详尽地介绍了人工角膜的研究进展，人工角膜的出现为那些由于所患角膜疾病不能应用穿透型角膜移植术或者缺乏条件而无法施行角膜移植术的患者带来了希望。自人工角膜诞生至今，人们在其材料和结构等方面进行着不断的研究，今后，人工角膜的研究重点是周边支架与受体组织的整合。

生物玻璃陶瓷的生物相容性及其与角膜生物愈合特性的研究

目的:研究生物玻璃陶瓷（Bioglass Ceramic,BGC）在角膜中的生物相容性及其与角膜的生物愈合特性,寻找人工角膜支架材料。方法:将孔径20～70μm、孔隙率37～62％、厚度0.5mm、前后曲率半径7.8 mm、直径6mm的BGC分别植入11只新西兰白兔角膜板层中。裂隙灯观察并照相,不同时间取材进行光镜检查。结果:最长观察8个月,5只实验兔的植入物脱出,其中3只碎裂。术后第2、3周角膜新生血管增生明显。术后2个月,出现角膜浅层轻度混浊。光镜检查见植床内少量大小不一的灰色BGC团块,其间混杂红染物质,周围角膜见大量增生成纤维细胞成同心圆样排列。结论:BGC植入角膜后有较高的脱出率,孔隙率为51％,62％的BGC强度不够,植入后碎裂。BGC植入影响了角膜代谢,导致角膜前板层混浊。目前的切片技术与设备,较难获得良好的切片效果,难以评价BGC在角膜板层中的生物愈合特性。BGC目前的参数不适宜用于人工角膜的支架材料。眼科学报2001;17:198～201。

人工角膜的研究进展

详细介绍了人工角膜 (keratoprosthesis,KPs)的研究情况 ,描述了当前各种类型的人工角膜及其存在的缺点 ,并讨论了理想的人工角膜及组织工程化人工角膜应达到的要求。近年来的研究主要集中于运用多孔高分子材料作为中央 -周边型人工角膜的周边支架材料 ,改善材料的生物结合能力。

严重眼外伤前后段联合手术中临时人工角膜的应用

目的 观察临时人工角膜用于严重眼外伤眼前后段联合手术的远期疗效。方法 分析 3 8例 (3 8眼 )由于眼球破裂伤导致眼前后段严重损伤 ,实施临时人工角膜下的晶状体玻璃体切除、眼内异物摘出、视网膜复位及穿透性角膜移植联合手术的效果及相关因素的影响。结果 术后随访 6月～ 6年 ,平均 2年。保存 0 .0 2以上有用视力者 2 3眼 (61% ) ,眼球萎缩 2眼。 9眼合并眼内异物全部摘出成功 ,2 0眼合并视网膜脱离者 ,术后再脱离 4眼 ,16眼复位 (80 % )。 2 8眼角膜植片保持透明 (74% ) ,2次移植 5眼 ,3次移植 1眼 ,4眼植片半透明仍在观察中。结论 在临时人工角膜下的眼前后段联合手术使部分患者经过 1次手术达到复明目的。

人工角膜支架材料的实验研究

目的 :观察 3种人工角膜支架材料在动物体内的生物学反应。方法 :将多孔材料、Polyester材料和膨体聚四氟乙烯三种材料切成直径 6mm的圆盘状。分为处理组和对照组。处理组的材料经氩等离子体处理。把 4 2只新西兰大白兔分为 7组 ,每组 6只兔 ,3组为实验组 ,3组为对照组 ,1组为手术对照组。将盘状支架材料手术植入角膜板层囊袋内。术后第 4 2、84天取角膜进行角膜组织学及生物化学分析。结果 :材料处理组角膜水肿明显减轻 ,8周后 3种材料中角膜水肿均消失。多孔材料和polyester材料植入后新生血管出现延迟 ,范围较小 ,炎细胞浸润也明显减少。术后 6周纤维细胞迁徙材料内 ,术后 12周空腔填充大量纤维细胞 ,材料的厚度明显增加。同时葡萄糖氨基聚糖分析发现 ,KeratinSulfate (KS)含量降低 ,DermatinSul fate(DS)含量增高 ,并有大分子葡萄糖氨基聚糖出现。材料处理与否不影响胶原蛋白及葡萄糖氨基聚糖的沉积。结论 :支架材料经氩等离子体处理可明显减轻角膜炎症反应 ,增加材料内间质蛋白的沉积 。

人工角膜植入术后患者生活质量及影响因素调查

目的应用国家眼科研究所视觉相关生活质量量表(NEI-VFQ-25)调查人工角膜患者的生活质量并探讨影响其生活质量的主要因素。方法对2005年12月-2015年12月99例在我院行人工角膜植入术患者进行生活质量问卷调查。根据1973年世界卫生组织制订的视力损伤标准^([1])将人工角膜患者视力划分为非低视力(≥0.3)组、低视力(0.05~0.3)组和盲(<0.05)组。结果术后非低视力组得分为65.63±13.35,低视力组得分为44.23±10.61,盲目组得分为20.97±5.77。结论人工角膜患者术后虽可获得一定视力,但生活质量依旧不乐观,生活质量与术后视力和个人收入呈正相关。

人工角膜研究进展

人工角膜的研制在近年来有了较大的进步,非组织工程化人工角膜在材料选择?处理和设计方式上有所创新,同时具有活性的组织工程化人工角膜的出现为人工角膜的研制开辟了一条新途径.

羟基磷灰石表面修饰的人工角膜钛支架体外生物相容性研究

目的采用细胞培养法观察人工角膜纯钛支架经羟基磷灰石(HA)表面修饰后,其生物相容性是否增加。方法采用第4～6代兔角膜基质成纤维细胞直接接种于HA-Ti、Ti及盖玻片表面,培养3、24、48、72h后,用丫啶橙染色法观察材料表面细胞的黏附、伸展和增殖情况,在扫描电子显微镜下观察材料表面的细胞形态及细胞外基质产生情况。结果细胞接种3、24、48、72h后,HA-Ti表面的活细胞数多于其他材料表面(P<0.05)。细胞接种3h,细胞扩展面积:HA-Ti>盖玻片>Ti。48h后扫描电子显微镜观察发现HA-Ti表面的细胞扩展面积最大,细胞张力丝最长。72h后,HA-Ti表面完全被胶原覆盖。结论HA表面修饰增加了人工角膜纯Ti支架的生物活性。