圆锥角膜患者表面角膜镜片术后镜片细胞和神经重建的活体动态观察

目的：应用共焦显微镜观察圆锥角膜患者表面角膜镜片术（epikeratophakia,EP)后不同时期的镜片组织,了解低温冷冻脱水角膜材料移植后组织细胞和神经重建的动态过程。方法：对24例（24只眼）圆锥角膜患者行EP,应用共焦显微镜分别对术后不同时期的角膜镜片组织细胞、神经重建过程进行活体动态观察,并摄像记录。结果：镜片上皮层：术后3或4d,组织镜片表面已被角膜表层上皮细胞覆盖,镜片边缘可见翼状细胞及形态不规则、低密度的基底细胞;术后1个月,上皮基底细胞完全覆盖角膜镜片;术后6个月,基底细胞密度及形态趋于正常,可见上皮下散在神经丛;术后2年,神经丛形态接近正常。镜片基质层：术后1年内,镜片基质细胞无变化,细胞少、形态不规则;术后2年,镜片边缘偶见正常形态的基质细胞;术后5年,镜片中央仍未见正常形态的基质细胞,镜片前后基质细胞相同。镜片基质神经：术后6个月,有神经干伸入镜片基质内,术后2年,基质神经数量增多;术后5年,基质神经尚未达到正常密度。结果：冷冻的非活性角膜组织行EP后组织镜片各层细胞、神经重建的时间各不相同,但并不影响植片透明度。     

异种表面角膜镜片术

目的介绍异种表面角膜镜片术（ＨＥＰ）的动物实验和临床应用。方法异种（人给猴）表面角膜镜片术（ＥＫＰ）动物实验进行了８例，术后不同时间进行了组织病理学检查。临床上给４例圆锥角膜和９例无晶体眼进行了异种（猴→人）ＥＫＰ术。结果８例实验动物有７例异种表面角膜镜片获得透明，术后镜片上皮化４～６ｄ完成，基质内角膜细胞再分布一般在９个月完成，观察时间６～２４个月。９例无晶体眼７例成功，４例圆锥角膜全部成功，观察时间５～３２个月，视力均有提高。结论异种ＥＫＰ术可以成为治疗圆锥角膜和单眼无晶体眼的一种改良手术     

异种表面角膜镜片术的动物实验和初步临床应用

对５只实验猴进行了异种（人→猴）表面角膜镜片术，术后７￣１０天上皮完全覆盖镜片，３￣６个月角膜细胞再生，排列正常，结果４只实验镜片透明愈合，没有发生排斥反应。１只实验猴术后发生层间上皮植入性囊肿。观察时间：３￣２４个月。在临床上为２例单眼无晶体眼进行了异种（猴→人）表面角膜镜片术，术后镜片稍有水肿，以后逐渐消失，５￣８天上皮完全修复，镜片一直透明，没有发生排斥反应，视力也得到了明显改善。     

异种表层角膜镜术的实验研究

在猴-猴表层板层角膜移植术成功的基础上,进行了三例人-猴异种表层角膜镜片术。术眼均获透明愈合。观察期分別为1个月、3个月和2年。对3例表层角膜镜片术的术眼角膜进行了组织学检查,发现上皮厚度及基质角膜细胞正常,进行异种表层角膜镜片术必须根据以下三个因素:供受体组织结构和屈光参数相近;供体角膜要有前弹力膜和一定的厚度。另外,对手术方法也进行了某些改进。     

表层角膜镜片术的进展

表层角膜镜片术是在去除上皮的患眼角膜表面移植经切削加工而具有不同屈光度的角膜板层移植片,用以矫正屈光状态的一种屈光性手术。近年来取得了不少进展,冷冻切削角膜表层镜片更加精细及准确。为能保存活细胞,使术后视力及透明度迅速恢复,实验研究了各种非冷冻切削镜片方法,临床应用大有前途。不作角膜楔形切除的术式已被大多数学者接受。术后并发症种类有所增加,术后上皮化异常及欠矫,过矫为主要并发症。为减少这两种并发症,进行了大量的临床研究。生物粘合剂(Tisseel MAP-COX)、激光可代替缝线或减少缝线针数,但尚处于实验阶段,可望用于临床。临床应用表层镜片术治疗无晶体眼,圆锥状角膜,高度近视及角膜病变取得较好效果。异种表层镜片术仍处于实验阶段,其前景广阔。     

角膜表面镜片术的实验研究

目的研究兔角膜表面镜片术后不同时期的角膜变化及免疫状态的改变。方法应用组织学及免疫组化染色法对２０只兔角膜表面镜片术后的角膜上皮修复、层间愈合、内皮细胞及上皮中郎格罕细胞（Ｌａｎｇｅｒｈａｎｓｃｅｌ，ＬＣ）进行动态观察。结果术后第４～１２天，平均７．７天上皮修复，１个月恢复正常形态和功能。术后第７天和１４天分别在镜片的周边部和上皮侧中央部出现少量角膜细胞，２个月时角膜细胞恢复正常。术后３天角膜缘部ＬＣ开始增加，１４天达高峰，２个月恢复正常。结论该手术对内皮细胞无明显影响，２个月时层间愈合良好，各层恢复正常，未发现免疫反应，为一种简便、安全的屈光手术。     

准分子激光角膜切削术治疗角膜表面镜片术后散光

评价准分子激光角膜切削术治疗角膜表面镜片术后散光的效果。采用Ｃｏｈｅｒｅｎｔ产ＳＣＨＷＩＮＤＫＥＲＡＴＯＭ准分子激光治疗系统对８例１２只眼角膜表面镜片术后散光进行治疗，均为圆锥角膜术后病例，术前柱镜屈光度为－１．７５—－１０．００Ｄ，平均－５．４９Ｄ±３．２１Ｄ。术后随访６—１５月，平均１１．８月，显示裸眼视力均明显提高，矫正视力与术前相比提高者７只眼（５８．３３％）。柱镜平均屈光度由－５．４９Ｄ下降至－２．７７Ｄ，均无明显术后痛疼，术后角膜雾状混浊均不显著。说明准分子激光角膜切削术可有效地治疗角膜表面镜片术后的角膜散光，能显著地提高角膜表面镜片术治疗圆锥角膜的最终效果。     

异种表面角膜镜片术与泪液前列腺素E2含量的变化

目的对正常人和异种表面角膜镜片术（ｅｐｉｋｅｒａｔｏｐｈａｋｉａ，ＥＫＰ）后患者泪液前列腺素Ｅ２（ＰｒｏｓｔａｇｌａｎｄｉｎＥ２，ＰＧＥ２）含量的变化进行了测定，以评价异种ＥＫＰ与免疫反应之间的关系。方法对９例９眼施行了异种（恒河猴）ＥＫＰ，术前及术后１、３、７、１４、３０和６０天分别对９例患者的泪液ＰＧＥ２含量进行放免测定，随机选择１０名健康志愿者作为对照。结果异种ＥＫＰ术后泪液ＰＧＥ２含量显著增加，术后第２周达最高水平，为２７．２９μｇ／Ｌ，比正常对照组高出３．１倍，随后逐渐下降，但术后２个月仍高于术前水平。结论作者认为异种ＥＰＫ能诱导ＰＧＥ２的释放，进而导致免疫反应。术后ＰＧＥ２含量的早期变化可能是手术炎症与免疫应答的综合结果，而后期则与异种镜片抗原持续刺激单核—巨噬细胞释放ＰＧＥ２有关。术后早期局部应用类固醇激素和环氧酶抑制剂如消炎痛有利于减少ＰＧＥ２的释放从而抑制排斥反应的发生。     

表面角膜镜片术后视力不良病例的角膜地形图研究

报告5例无晶体眼行表面膜镜片术后9个月,视力不良病例的角膜地形图变化,发现所有病例角膜组织镜片明显偏中心,角膜前表面屈率呈极不规则性改变,这些提示手术中定角膜光学中心,进行标准的角膜组织镜片切削,按正规方法手术是表面角膜镜片术取得满意效果的基础。     

表面角膜镜片术治疗Terrienˊs边缘角膜变性初步报告

目的:探讨用表面角膜镜片术治疗严重的Terrien＇s边缘角膜变性的效果方法:全部病例为严重的周边角膜环形或部份变薄,厚度小于正常1/3,用带2mm环形巩膜的全角膜板层移植片移植到去除上皮的角膜植床。手术前及手术后定期行角膜曲率,散瞳验光检查。结果:本组病例随访时间3～13个月,平均10个月。随访期间,镜片全部透明。术前角膜散光平均11.5D,术后散光平均3.9D。术后矫正视力除一例稍降外,3例有提高。术后合并症和其它表面角膜镜片术一样,主要是镜片下混浊。本组一例因层间上皮植入性混浊位于视轴区而作了镜片更换术。结论:角膜表面镜片术治疗严重Terrien＇s边缘角膜变性,具有操作简单、方便、有效。它不但增加病变区的角膜厚度,而且手术是在角膜表面操作,不损伤Bowman氏膜,使中央角膜透明度得以保护。同时也降低角膜的散光度。眼科学报1997;13:79～81。     

Detection of HLA antigens in human epikeratophakia lenticules

We compared the distribution of HLA-ABC (Class I) and HLA-DR, -DQ, and -DP (Class II) antigens in fresh, non-lyophilized human cornea with that of rehydrated lyophilized epikeratoplasty lenticules. Class I antigens were detected at similar levels in both the control corneas and the epikeratophakia lenticules. Class II antigens, which were limited to cells at the limbus of control corneas, were absent from the epikeratophakia lenticules. Although epikeratophakia lenticules are not necessarily immunogenic, these results clearly demonstrate that they are antigenic and express selected major histocompatibility antigens. In the context of these findings, we discuss the lack of reports of immunologic rejection following epikeratoplasty.     

Corneal sensitivity after epikeratophakia

Corneal sensitivity was tested in 60 eyes of 30 patients who underwent unilateral epikeratophakia for the correction of aphakia (20 patients) or keratoconus (10 patients). Postoperative recovery time ranged from 2 months to 21 months (mean: 10 months). Our results indicate a relative hypesthesia of the epikeratophakia lenticule when compared with the peripheral host cornea and contralateral control cornea. However, corneal sensitivity tested in 11 patients with more than 1 year follow-up was increased compared with the sensitivity of 19 patients whose postoperative recovery was less than 1 year. Histopathologic findings in two lenticules from a nonhuman primate demonstrated sparse epithelial axon terminals. Host corneal nerves appear to innervate the lenticules by intraepithelial extension and by penetration of the superficial keratectomy scar.     

Long-term reversibility of epikeratophakia

PURPOSE: To assess the long-term reversibility of epikeratophakia. METHODS: Three human epikeratophakia lenticules (from 3 patients) were removed 7-14 years after refractive keratoplasty for aphakia (n = 1) and myopia (n = 2). Reasons for removal were irregular astigmatism (n = 1), opacities in the graft and host cornea, and progressive myopia (n = 2). After removal, 2 patients underwent cataract extraction and 1 underwent secondary implantation of AC-IOL. Visual acuity, refraction, keratometry, and corneal topography were assessed before and after removal of the lenticule, as well as after the cataract and IOL implantation, and were compared with the initial visual acuity and corneal curvature before epikeratoplasty. RESULTS: After removal of the lenticule, the 3 patients regained the initial curvature of the cornea (pre-epikeratoplasty), and remained stable during 6 months of follow-up. Initial best-corrected visual acuity and refraction before epikeratoplasty were restored after removal of the epikeratoplasty lenticule in the aphakic patient. Original best-corrected visual acuity was restored in the 2 myopic cataract patients after cataract extraction and IOL implantation. CONCLUSIONS: In a small care series, epikeratophakia was found to be a reversible procedure even after 7-14 years.     

Refractive keratoplasty. Histopathology of clinical specimens

Two keratophakia (KF), one epikeratophakia (EKP), three myopic keratomileusis (MKM), and three hypermetropic keratomileusis (HKM) specimens obtained 3.5 to 31 months following refractive keratoplasty were evaluated. The corneas were removed at keratoplasty due to postoperative complications, such as corneal edema, irregular astigmatism, delayed reepithelialization, stromal ulceration, epithelial interface ingrowth, and loss of visual acuity. The KF specimens demonstrated viable epithelium in the recipient-donor lenticule interface, disruption of the normal collagen lamellar pattern in the lenticule, and absence of keratocytes. All of the keratomileusis lenticules and the one epikeratophakia lenticule had variable keratocyte repopulation. All specimens showed irregular epithelial maturation. In one case of myopic keratomileusis, ferritin-like particles were found in the epithelial intercellular spaces. Folds in Bowman's membrane were seen in several keratomileusis lenticules; in one case, breaks in Bowman's membrane (BM) were seen.     

Fate of lyophilized xenogeneic corneal lenticules in intrastromal implantation and epikeratophakia

The antigenicity of intrastromal and epikeratophakia xenografts of lyophilized corneal tissue was evaluated in nonimmune and immune recipients. Lyophilized feline lenticules were implanted into intrastromal pockets in unsensitized rabbits and rabbits sensitized to the donor cat. In both cases, the grafts remained clear. Sensitized rabbits with clear intrastromal grafts received fresh tissue penetrating keratoplasty grafts from the same donor cat, placed adjacent to the intrastromal grafts. The fresh tissue penetrating keratoplasty grafts were rapidly rejected, while the lyophilized intrastromal grafts remained clear. Cats sensitized to rabbits received lyophilized and rehydrated epikeratophakia grafts shaped from rabbit cornea; these lyophilized grafts also remained clear for the 3-month period of the study. The results indicate that lyophilized and rehydrated corneal stroma, which is devoid of living cells, is not antigenic and is not subjected to immunologic attack, even in cases where the donor and host are of different species and the host has been previously immunized to the donor.     

飞秒激光辅助的角膜基质透镜植入术矫正远视的早期临床观察

目的　探讨飞秒激光辅助的角膜基质透镜植入术矫正远视的早期安全性及疗效。方法　前瞻性研究。对7例9眼远视患者行飞秒激光辅助的角膜基质透镜植入术，术后随访6个月。观察术后裸眼远视力、裸眼近视力、最佳矫正远视力、等效球镜度数、眼压、角膜曲率、角膜一般情况及神经生长情况等。结果　所有患者手术均顺利完成，仅1例（1眼）术后4个月发生角膜排斥反应。术后早期角膜基质水肿，术后1个月、3个月水肿消失；术后6个月，透镜与周边组织完全融合，无法识别边界。术后各时间点裸眼近视力、裸眼远视力、等效球镜度数均较术前改善，角膜平坦轴曲率、角膜陡峭轴曲率、中央角膜厚度均较术前明显增加。术后角膜平均曲率及眼压与术前比较变化不大，差异均无统计学意义（均为P＞0.05）。术后角膜OCT检查显示（除发生角膜排斥反应的1眼外）角膜表面光滑，基质透镜透明、在位。术后角膜激光共聚焦显微镜检查:术后1周，角膜组织水肿，透镜组织及角膜基质层均可见活化的角膜基质细胞，随时间延长，角膜水肿消退，基质细胞逐渐呈静止状态，并可见神经纤维。结论　飞秒激光辅助的角膜基质透镜植入术矫正远视早期是安全有效的，但其可预测性有待提高，远期疗效还需进一步随访观察。     

Experimental epikeratophakia using tissue lathed at room temperature.

This report presents for the first time the results of carrying out epikeratophakia with tissue lathed at room temperature. Using an experimental model of epikeratophakia in the rabbit, we evaluated tissue handling techniques for the preparation of donor lenticules. Details of the technique are described and the in-vivo and histopathological findings reported.     

准分子激光角膜切削术治疗圆锥角膜行角膜表层镜片术后的屈光不正

目的探讨角膜表层镜片术（EP）联合Ⅱ期准分子激光角膜切削术（PRK）治疗圆锥角膜完成期的临床疗效。方法（1）病例入选标准：①EP入选标准：圆锥角膜完成期患者,角膜中央区无瘢痕,最佳矫正视力（BCVA）≤0．3,角膜曲率≤60．0D;②Ⅱ期行PRK入选标准：角膜拆线后3个月内散光变化〈0．5D,年龄〉18岁,无其他眼部疾病。（2）手术治疗：对进入手术入选标准的患者常规Ⅰ期行EP,Ⅱ期行PRK。（3）术后随访：观察术后植片情况,记录视力、散光变化及并发症发生情况。结果8例（10只眼）患者接受了Ⅰ期EP联合Ⅱ期PRK,术后平均随访时间为40．6（30～94）个月。（1）视力：EP术后12～18个月（角膜全拆线行PRK术前）,10只眼BCVA均〉0．3,其中0．3～0．5者1只眼,≥0．5者9只眼;行PRK术后〉12个月,10只眼BCVA均≥0．5,其中5只眼BCVA达到1．0。（2）角膜散光：EP术前平均角膜散光为（7．3±1．8）D,EP术后12～18个月平均角膜散光为（3．8±1．6）D,PRK术后24个月以上,平均角膜散光为（1．6±0．9）D。（3）植片情况：EP术后所有植片透明,无免疫排斥反应发生。PRK术后1只眼发生0．5级的角膜上皮下雾状混浊,未见圆锥角膜复发。（4）术后并发症与处理：1例（1只眼）患者EP术后当天继发青光眼,前房消失,急诊行前房重建后缓解;1例（1只眼）患者EP术后植床出现较大皱褶,1例（1只眼）患者EP术后3个月内缝线松动,行植片重缝后缓解。结论Ⅰ期EP联合Ⅱ期PRK可能是治疗圆锥角膜完成期的有效方法,行PRK术后视力长期稳定。     

Physiologic analysis of corneal healing after epikeratophakia.

The evaluation of epithelial permeability, stromal transparency, and endothelial cell density is essential to determine the resumption of normal function in each corneal physiologic unit after refractive surgical procedures. The authors report the results of a prospective study conducted in 55 consecutive patients undergoing epikeratophakia using prelathed, lyophilized tissue lenses. Epithelial permeability was evaluated by means of fluorophotometry preoperatively and 1, 2, 4, 8, 12, 24, and 52 weeks after epikeratophakia. With few exceptions, Scheimpflug photography also was performed at the same examination times to assess stromal optical density. Endothelial cell counts were performed in each patient preoperatively and between 6 and 12 months postoperatively. The epithelial barrier function resumed normal values within 8 weeks after epikeratophakia. The optical density of both donor lenticule and recipient corneas was initially increased but returned to values comparable with those of unoperated corneas by 12 weeks postoperatively. Endothelial cell density was not affected by epikeratophakia. These results confirm the authors' preliminary observation that epikeratophakia allows a relatively quick recovery of normal corneal functions and should prompt investigators to demonstrate the safety of other refractive surgical procedures in a similar way.