增视性角膜移植术后角膜植片透明率及影响因素

目的：探讨增视性角膜移植术后角膜植片的透明率及其影响因素。 方法：回顾性病例研究。选择2004-01/2005-12于青岛眼科医院行增视性穿透性角膜移植术（optical penetrating keratoplasty,PKP）的患者97例105眼,包括圆锥角膜,角膜基质营养不良,外伤、感染等因素导致的角膜白斑,单纯疱疹病毒性角膜炎稳定期,角膜内皮细胞功能失代偿等。统计分析术前视力及术后最佳矫正视力、角膜植片透明情况、内皮细胞计数、是否排斥、植片混浊原因,采用R×C表及四格表的χ2检验。 结果：增视性PKP术后角膜植片透明率：术后1a 89.8%,术后2a 83.7%,术后3a 78.3%,术后4a 67.1%,术后5a 63.6%。术后5a时圆锥角膜角膜植片透明率最高,达94.1%,角膜内皮功能失代偿最低,为14.3%。术后最佳矫正视力0.05~1.0,0.8以上者圆锥角膜所占比例最多,达72.5%,角膜内皮功能失代偿最少,占6.3%。导致角膜植片混浊的主要原因为角膜植片免疫排斥及角膜植片内皮细胞功能失代偿。 结论：增视性PKP术后角膜植片透明率逐年稳定下降,相邻两年之间无显著性差异;原发病不同,角膜植片透明率有差异,圆锥角膜手术效果最佳;角膜植片混浊的主要原因为免疫排斥及角膜植片内皮功能失代偿。     

甘油冷冻保存角膜深板层角膜移植术治疗圆锥角膜

目的分析甘油冷冻保存角膜深板层角膜移植术（DALK）治疗圆锥角膜术后角膜内皮细胞密度及屈光状态变化。方法回顾性病例研究。分析圆锥角膜患者用甘油冷冻保存的角膜材料行DALK治疗的44例（49眼）病例资料,其中17例（17眼）患者于术后1个月、1年、2年、3年、4年按期进行随访,且随访资料完整。分析术后角膜内皮细胞丢失率、视力以及屈光状态。结果患者平均随访时间为（39．0±12．6）个月,无一例发生植片免疫排斥。术前平均内皮细胞密度（ECD）为（2597±578）个／mmz．术后1个月、1年、2年、3年、4年时平均ECD为（1790±409）cells／mm2、（1703±443）cells／mm2,（1632±389）cells／mm2、（1638±357）cells／mm2、（1675±283）cells／mm2、（1611±421）cells／mm2。术后4年ECD较术前减少34．2％。术前平均裸眼视力（UCVA）为（1．40±0．60）logMAR,平均最佳矫正视力（BCVA）（0．98±0．54）logMAR,术后1个月、1年、2年、3年、4年平均BCVA分别为（0．44±0．12）logMAR、（0．36±0．20）logMAR、（0．32±0．23）logMAR、（0．29±0．20）logMAR、（0．27±0．16）logMAR。结论使用甘油冷冻保存的角膜材料的角膜移植术治疗圆锥角膜可获得较好的视力,角膜内皮细胞丢失率低．远期疗效较好。     

穿透性角膜移植术后慢性失功移植片的超微结构观察

目的探讨穿透性角膜移植术后慢性失功能移植片的超微结构改变及发生机制。方法角膜植片慢性失功（CCAD）组：穿透性角膜移植（PK）术后因CCAD导致移植失败的12只（12例患者）角膜植片;12例患者两次PK手术的平均间隔时间为69个月,10例患者初次PK术后曾发生1次或以上免疫排斥反应,2例患者未发现免疫排斥反应;正常对照组：由山东省眼库提供的5只角膜植片作为正常供体。对两组角膜片行组织病理学、透射电镜及扫描电镜检查,结合患者的病史进行综合分析。结果透射电镜观察发现CCAD组较正常对照组角膜上皮层变薄,可见大空泡形成,角膜基质层纤维排列紊乱,无明显炎性细胞浸润;后弹力层与角膜内皮细胞之间可见异常的间隙及纤维增生;角膜内皮层萎缩变薄,细胞变形、核染色质浓缩,偶见炎性细胞与角膜内皮细胞黏附。扫描电镜观察发现CCAD组较正常对照组角膜上皮细胞微绒毛数量明显减少,暗细胞增多;角膜内皮细胞数量减少,存在缺失区,内皮细胞可见凋亡小体。结论CCAD植片特征性超微结构改变是内皮细胞的萎缩性改变和非炎性细胞成分的纤维增生。慢性亚临床的抗原依赖与非抗原依赖因素可能共同参与了CCAD的发生,免疫排斥反应可能诱导和促进了CCAD的发生、发展。     

飞秒激光辅助角膜内皮移植术治疗大泡性角膜病变的疗效观察

目的：评估飞秒激光辅助的后弹力层撕除角膜内皮移植术治疗大泡性角膜病变的临床疗效及安全性。方法：回顾性分析2013－03／2014－02在我科住院治疗的大泡性角膜病变患者15例16眼,其中男7例7眼,女8例9眼,平均年龄66．3±18．4岁,采用飞秒激光制作薄层角膜内皮植片,进行后弹力层撕除角膜内皮移植术。术后随访12mo,观察角膜刺激症状消退、植片恢复和并发症等情况,观测指标包括最佳矫正视力、眼压、前节光学相干断层扫描及角膜内皮细胞计数。结果：所有患者手术顺利,无术中并发症发生;术后眼压正常,最佳矫正视力较术前不同程度提高。角膜刺激症状自术后1d 开始逐渐减轻,术后3wk 完全缓解。术后1眼（6％）发生内皮植片脱位,3眼（19％）植片与植床之间存在局灶性层间积液。术后1 mo角膜上皮变光滑,基质水肿消退,中央角膜厚度（638±86．51μm ）较术前（811±137．55μm）明显变薄。随访期间,发生植片急性排斥反应和植片内皮功能失代偿各1眼（6％）。末次随访,角膜内皮细胞计数为1687±507个／mm2。结论：应用飞秒激光辅助后弹力层撕除角膜内皮移植术治疗角膜内皮病变,可以个体化、精确、高效地制作内皮植片,手术安全性高,术后恢复快。     

前部深板层角膜移植治疗急性圆锥角膜的临床研究

目的评价前部深板层角膜移植术治疗急性圆锥角膜的效果。方法采用临床病例观察方法。分析在南京宁益眼科中心接受前部深板层角膜移植术的急性圆锥角膜5例（5只眼）。采用前房注气联合逐步板层分离技术,植床直径7．5～8．0mm。供体为新鲜和冷冻保存角膜。观察术前和术后1、3、6个月和1年以上裸眼视力、矫正视力、移植片透明性、中央区角膜厚度、中央角膜内皮细胞密度和形态以及排斥反应发生的情况。结果术前视力：手动／5～10cm,术后1年平均裸眼视力0．26±0．16,平均最佳矫正视力0．42±0．23;平均球镜度（-2．75±0．94）D,柱镜度（-2．56±0．83）D;术前平均中央角膜厚度（279．33±312．30）μm,术后1年厚度为（557．20±37．48）μm;术前角膜内皮细胞形态和计数不能测量,术后3个月至术后1年内皮细胞数量无明显变化,中央角膜平均内皮细胞计数（1967±228．51）个／mm^2;新鲜植片透明性高于保存植片;超声生物显微镜检查：术前病变角膜向前隆起,基质层有囊泡结构,纤维成分减少,回声增强;术后以上改变均消失。术中2眼发生后弹力层微小穿孔,但没改变术式;术后无双前房或排斥反应发生。结论急性圆锥角膜可不造成角膜内皮细胞数量、形态的严重损害：采用前部深板层角膜移植治疗急性圆锥角膜短期临床效果良好。     

穿透性角膜移植植片内皮慢性失功与细胞衰老

穿透性角膜移植术后角膜植片的远期透明率并不理想,角膜植片内皮慢性失功可能是其主要原因。当前认为,细胞加速衰老现象是多种器官移植物慢性失功的重要原因,角膜植片内皮慢性失功也可能与之有关,而其研究尚处于起步阶段。为此,特对相关领域研究现状作一综述。     

重力液流系统和主动控制液流系统对白内障超声乳化术中累积释放能量及术后视力恢复和角膜内皮参数的影响

目的　对比重力液流系统和主动控制液流系统对白内障超声乳化手术中累积释放能量（cumulative dissipated energy,CDE）及术后视力恢复、角膜内皮参数的影响。方法　选取2017年10月至12月于首都医科大学附属复兴医院眼科行白内障手术患者96例（96眼）。所有患者均患有年龄相关性白内障,LOCS III晶状体核透光性和晶状体核颜色评分为4.0~6.9分。依照液流系统选择情况分为:重力组（48例48眼）,使用Centurion重力液流系统;主控组（48例48眼）,使用Centurion主动控制液流系统。术中记录每例患者CDE;术后1周、1个月、3个月复诊,行眼科常规检查,包括视力、眼压、裂隙灯、眼底镜等;所有患者术前行非接触角膜内皮镜检查,记录角膜内皮细胞密度（endothelial cell density,ECD）、内皮细胞变异系数（coefficient of variance,CV）、角膜六角形内皮细胞比率（percentage of hexagonal endothelial cells,6A）及中央角膜厚度（central corneal thickness,CCT）。每次复查均行角膜内皮镜检查获取ECD、内皮细胞CV、6A、CCT等数据。结果　术前重力组和主控组患者的年龄、性别、晶状体核透光性、晶状体核颜色评分比较,差异均无统计学意义（均为P＞0.05）。术前两组患者最佳矫正视力比较,差异无统计学意义（P＞0.05）,术后1周主控组患者最佳矫正视力较重力组明显提高,差异有统计学意义（P＜0.05）,术后1个月和3个月两组间最佳矫正视力差异均无统计学意义（均为P＞0.05）。重力组与主控组术中CDE差异无统计学意义（P＞0.05）。总体CDE均与术前晶状体核分级呈正相关性（晶状体核透光性:r=0.703,P=0.001;晶状体核颜色评分:r=0.804,P=0.000）,术前晶状体核分级越高术中CDE越大。重力组和主控组术前ECD、内皮细胞CV、6A、CCT相似,差异均无统计学意义（均为 P＞0.05）。术后1周ECD、内皮细胞CV、6A比较,两组间差异均无统计学意义（均为P＞0.05）,但重力组CCT［（570.60±34.99）μm］明显大于主控组［（554.67±30.71）μm］,差异有统计学意义（P＜0.05）;术后1个月和3个月两组ECD、内皮细胞CV、6A、CCT比较,差异均无统计学意义（均为P＞0.05）。结论　Centurion超声乳化手术系统中重力液流系统及主动控制液流系统对术中CDE及角膜内皮的影响相似,主动控制液流系统能够更有效地减轻术后角膜水肿,使患者在术后早期视力恢复更迅速。     

抗青术后白内障行Phaco后角膜内皮和形态学参数的变化

目的:比较抗青光眼术后白内障眼和正常白内障眼行超声乳化手术后角膜内皮和角膜形态学参数的变化。方法:前瞻性系列病例研究。 我院2010-01/12行白内障超声乳化患者160例200眼,其中包括抗青光眼术后白内障和正常眼白内障各100眼。以抗青光眼术后白内障作为实验组,正常眼白内障作为对照组。用非接触角膜内皮显微镜（SP-2000P）分别于术前,术后1, 3mo测量角膜内皮密度（endothelial cell density,ECD）;用Pentacam分析仪分别于术前,术后1,3mo测量角膜形态学参数,包括角膜中央厚度（central corneal thinkness,CCT）和角膜体积（corneal volume,CV）。结果:术前实验组平均的ECD（1203±245个/mm²）比对照组（2648±167个/mm²）小（P＜0.01）,而实验组的平均CCT（543±32μm）值较对照组（525±36μm）大（P＜0.01）,实验组的平均CV(59.14±2.79mm³)值较对照组（57.26±3.24mm³）大（P＜0.05）,有统计学意义。术后1,3mo实验组平均的ECD较对照组明显减少（P＜0.01）,而CCT值较对照组明显增加（P＜0.01）,CV值较对照组也明显增加（P₁＜0.01,P₂＜0.05）,有统计学意义。术后1,3mo角膜内皮细胞丢失百分率（％）在实验组比对照组大（P₁=01145,P₂=0.2018),但无统计学意义。CCT值增加百分率（％）实验组比对照组在1mo时要显著增加（P=0.0142）,有统计学意义,而在3mo时两者无明显差异（P=0.3562）。CV值增加百分率（％）实验组比对照组在1mo时要显著增加（P=0.0134）,有统计学意义,而在3mo时两者无明显差异（P=0.4538）。结论:抗青光眼术后白内障眼术前ECD较正常眼低,行白内障超声乳化手术术后的角膜内皮细胞丢失率比正常眼要大,术后短期角膜水肿较正常眼严重,所以抗青光眼术后白内障眼只有更精密的规划手术和更精细的手术操作,才能在术中尽量减少对内皮细胞的损害,缩短角膜水肿恢复的时间,降低术后角膜内皮失代偿的风险。     

穿透性角膜移植术后慢性失功移植片的免疫学研究

目的检测穿透性角膜移植术后慢性失功移植片的免疫与非免疫相关细胞因子表达的变化,探讨免疫与非免疫因素在角膜植片慢性失功中的作用机制。设计临床实验研究。研究对象分为两组,角膜植片慢性失功（CCAD）组：穿透性角膜移植（PK）术后因CCAD导致移植失败的8例患者的角膜植片;正常对照组：由山东跟库提供的正常角膜供体3只。方法免疫组化法检测两组角膜片免疫相关细胞因子表达,结合患者的临床资料进行综合分析。主要指标角膜中CD4^＋、CD8^＋、F4／80、TGF-β、bFGF、α-SMA的表达。结果免疫组化检测显示正常对照组：角膜各层组织 、α-SMA、bFGF表达阴性,F4／80角膜基质偶见表达,TGF-β在角膜上皮层有表达。CCAD组：所有角膜植片全层均术见CD4^＋及CD8^＋T淋巴细胞浸润;5例失功植片基质层F4／80阳性表达,其余3例角膜植片全层表达阴性;所有角膜植片上皮层可见TGF-β阳性表达,基质层内可见TGF-β表达。所有失功角膜片基质层bFGF表达呈弱阳性;所有患者角膜基质内α-SMA表达阳性,后弹力层附近可见较强表达。结论穿透性角膜移植术后慢性失功移植片免疫组化检查未发现支持临床急性免疫排斥反应的证据,抗原递呈细胞及非免疫特异相关细胞因子的异常表达提示免疫与非免疫因素参与了CCAD的发生和发展。     

重组牛碱性成纤维细胞生长因子对角膜内皮细胞密度低下患者白内障术后角膜内皮的保护作用

目的　研究角膜内皮细胞密度（ECD）低下患者行超声乳化白内障吸除术后应用重组牛碱性成纤维细胞生长因子（re-bFGF）对角膜内皮的保护作用。方法　前瞻性队列研究。选取2019年9月至2022年4月在北京大学第三医院眼科就诊、拟行超声乳化白内障吸除且合并ECD低下的患者80例 (90眼)为研究对象,随机分为两组,试验组41例(45眼),对照组39例(45眼)。术后除常规抗炎治疗外,试验组患眼应用re-bFGF滴眼液每日4次滴眼,对照组患眼应用1 g·L^-1玻璃酸钠滴眼液每日4次滴眼,均使用至术后6个月。对比分析两组患眼术前和术后1个月、3个月、6个月的ECD和中央角膜厚度（CCT）等。结果　术后1个月、3个月、6个月,试验组患眼的ECD和CCT均较术前变化不明显（均为P>0.05）,而对照组患眼的ECD均较术前下降,CCT均较术前增加（均为P<0.05）。术前,试验组和对照组患眼ECD分别为（1120.6±306.1）个·mm^-2、（1040.5±317.3）个·mm^-2 ,CCT分别为（543.1±51.6）μm、（546.8±35.6）μm,两组相比差异均无统计学意义（均为P>0.05）;术后6个月,试验组和对照组患眼ECD分别为（1271.3±288.6）个·mm^-2、（746.5±193.5）个·mm^-2 ,CCT分别为（542.0±55.3）μm、（583.5±45.3）μm,两组相比差异均有统计学意义（均为P<0.05）。术后2眼发生了角膜内皮失代偿,且均发生在对照组。结论　re-bFGF对ECD低下患者行超声乳化白内障吸除术后的角膜内皮有保护作用,可减轻超声乳化手术造成的ECD下降,减少角膜水肿及术后短期角膜内皮失代偿的严重并发症的发生率。     

Corneal endothelium after deep anterior lamellar keratoplasty and penetrating keratoplasty for keratoconus: a four-year comparative study

Purpose:

To compare the status of corneal endothelium and central corneal thickness within the first four postoperative years after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in patients with keratoconus.

Materials and Methods:

Thirty-nine eyes (Group A) which had PK and 44 eyes (Group B) which had DALK for the treatment of keratoconus were included in this retrospective study. The endothelial cell density (ECD), the mean endothelial cell area and the coefficient of variation of cell area were assessed with a non-contact specular microscope, and the central corneal thickness (CCT) was measured with an ultrasound pachymeter.

Results:

Mean ECD loss rate at two years was 36.24% in Group A and 18.12% in Group B (P<0.001). Mean ECD loss rate at four years was 47.82% in Group A and 21.62% in Group B (P<0.001). Mean annual ECD loss rate was calculated 14.12% per year in Group A and 5.78% per year in Group B. In the PK group, increase in mean CCT was 15.60% in two years and 15.03% in four years, while in the DALK group, mean CCT increased by 8.05% in two years and 9.31% in four years.

Conclusions:

As the majority of ectatic disorders such as keratoconus occur in young people, long-term endothelial cell survival following treatment with keratoplasty is essential for the long-term visual ability. Our finding that corneal endothelial cell loss in the DALK group occurs at a slower rate than in the PK group suggests DALK as a safer alternative to PK in these selected patients.     

Pilot study of transepithelial， very high fluence accelerated corneal collagen cross-linking in primary keratoconus

Objective Evaluate the safety and effectiveness of transepithelial, very high fluence accelerated corneal collagen cross-linking （A-CXL） in primary keratoconus. Methods Self-control study. Thirteen primary keratoconus eyes of 13 patients were treated with transepthelial, very high fluence A-CXL with a UVA intensity of 45 mW/cm2, an irradiation time of 2 min 40 s, and a total energy of 7.2 J/cm2. Routine ophthalmologic examination, UCVA, BCVA, refractive error, corneal keratometry, anterior and posterior elevation （AE and PE）, index of vertical asymmetry （IVA）, minimum corneal thickness （CT）, compensated intraocular pressure （IOPcc）, endothelial cell density （ECD） were evaluated pre-operatively and 7-day, 1-month, 3-month, 6-month, 12-month post-operatively. Results The UCVA （F=6.111, P＜0.01） and BCVA （F=9.734, P＜0.01） showed a statistically significant improvement by 12-month post-operatively. The decrease in spherical lens （F=5.871, P＜0.05）, steeper K-value （F=19.651, P＜0.05）, Kmax （F=3.253, P＜0.05）, AE （F=23.958, P＜0.01）, PE （F=20.832, P＜0.01） and IVA （F=4.068, P＜0.05） were statistically significant. CT （F=4.180, P＞0.05）, ECD （F=1.812, P＞0.05） and IOPcc （F=0.332, P＞0.05） were without significant change. Conclusion Transepithelial, very high fluence A-CXL is safe and effective in treating primary keratoconus.     

低渗核黄素角膜胶原交联术治疗圆锥角膜

目的评价低渗核黄素角膜胶原交联术治疗角膜较薄（角膜基质厚度＜400 μm）的圆锥角膜的临床疗效。方法回顾性病例研究。选取圆锥角膜患者8例（8眼）。所有患眼刮除角膜上皮后,行低渗核黄素角膜胶原交联治疗,观察治疗前,治疗后6、12个月,患者的矫正视力、屈光状态、最薄处角膜厚度及角膜内皮细胞密度的变化。结果治疗前患者最薄处角膜的厚度为418.0 μm,刮除角膜上皮后为383.5 μm,交联治疗后12个月为414.0 μm。治疗前角膜顶点的最大K值、BCVA、角膜内皮细胞密度分别为58.2 D、0.52（logMAR）和2 698.5 cells/mm2,治疗后12个月,上述数据分别为58.9 D、0.46和2 685.9 cells/mm2。结论低渗核黄素角膜胶原交联术是治疗角膜厚度＜400 μm的圆锥角膜有效、安全的方式之一。     

Changes in endothelial cell density following penetrating keratoplasty and deep anterior lamellar keratoplasty

AIM: To compare the corneal endothelial cell density (ECD) of clear grafts after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). METHODS: The study included 44 and 54 patients treated with PK and DALK, respectively, between March 2006 and April 2010. Corneal ECD was examined using specular microscopy at postoperative 1, 3, 6, 12, and 18 months, and the values were compared. RESULTS: Corneal ECD reduction in the PK group was 7.4%, 15.2%, 23.5%, and 28.9% at 3, 6, 12 and 18 months respectively after surgery, compared with 4.2 % in the first month (P<0.01). These figures were 3.0%, 6.7%, 7.2%, and 7.7% at 3, 6, 12 and 18 months respectively, compared with 2.2 % in the first month in the DALK group (P>0.05). CONCLUSION: Compared with DALK,PK significantly reduced ECD of the clear grafts. These results suggest that survival of endothelial cells in grafts is better after DALK than after PK.     

快速角膜胶原交联术治疗圆锥角膜的安全及有效性研究

目的　评价快速角膜胶原交联术（accelerated corneal collagen crosslinking,A-CXL）治疗圆锥角膜的安全性及有效性。方法　收集2017年4月至2018年3月在郑州市第二人民医院眼科确诊为进展期圆锥角膜的患者37例（61眼）,使用Avedro快速角膜胶原交联系统（30 mW·cm^-2,4 min）进行手术。随访12个月,观察术前及术后最佳矫正视力（best corrected visual acuity,BCVA）、角膜内皮细胞密度（endothelial cell density,ECD）、角膜内皮细胞面积变异系数（coefficient variation of cell size,CV）及六边形角膜内皮细胞比例（percentage of hexagonal cells,Hex）、等效球镜度（spherical equivalent,SE）、角膜前表面最大曲率（maximum keratometry,Kmax）、角膜后表面高度（posterior corneal elevation,PCE）、最薄点角膜厚度（thinnest corneal thickness,TCT）的变化。结果　术后1个月眼前段光学相干断层扫描检查发现39眼（63.9%）交联术后角膜前中基质层信号增强,可见明显分界线,深度（278.2±45.6）μm;角膜ECD和Hex分别较术前平均下降（97.6±138.6）个和（7.8±14.8）%,差异均有统计学意义（均为P<0.05）,术后3个月二者均恢复至术前水平;角膜CV由术前（35.6±8.0）%增加至（40.6±7.1）%,差异有显著统计学意义（P<0.01）;术后3个月时为（37.3±6.8）%,与术前相比差异仍有统计学意义（P<0.05）;术后6个月时恢复至术前水平。术后12个月,BCVA及SE均较术前明显改善,差异均有显著统计学意义（均为P<0.01）;Kmax及TCT分别下降（2.06±2.51) D和(8.9±10.8)μm,差异均有显著统计学意义（均为P<0.01）;PCE保持稳定,与术前差异无统计学意义（P>0.05）。结论　A-CXL手术后早期会出现短暂可逆性内皮细胞数量下降及形态改变,该手术可明显改善圆锥角膜患者角膜形态及视力,阻止或延缓角膜膨隆的进展。     

Short-term results of penetrating keratoplasty performed with the Femtec femtosecond laser

PURPOSE: To evaluate the use of the Femtec femtosecond (fs) laser for penetrating keratoplasty (PK) in the treatment of corneal diseases. DESIGN: Prospective, nonrandomized clinical study. METHODS: Nine eyes of nine patients underwent surgery for PK. Five had pseudophakic bullous keratopathy, three had Fuchs dystrophy, and one presented in a keratoconus patient. A Femtec (20/10 PerfectVision; GmbH, Heidelberg, Germany) fs laser was used to create penetrating cuts on donor and recipient corneas. All patients were evaluated for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), pachymetry, topography, and endothelial cell density (ECD). Scanning electron microscopy (SEM) was performed on corneal tissue after surgery. RESULTS: All eyes were treated successfully without intraoperative complications. The mean follow-up was 6 +/- 3 months. At the last postoperative examination mean BSCVA was 20/69 and there was a significant improvement (P = .08) in both UCVA and BSCVA. Mean astigmatism was 2.9 +/- 1.2 diopters. Mean ECD was 1194 +/- 465 cells/mm(2) with a mean cell loss after surgery of 49.8% +/- 19.8%. SEM displayed smooth rectilinear cut margins and minor remaining tissue bridges. One patient presented a retinal detachment three months after surgery that was successfully treated and two subjects showed an allograft rejection. CONCLUSION: Use of the Femtec fs laser was effective and safe to perform PK. Short-term visual results and refractive results are analogous to conventional PK or other fs laser-assisted PK studies. Longer-term follow-up of additional cases is necessary to precisely quantify the endothelial cell loss after fs surgery.     

Penetrating keratoplasty for keratoconus: long-term results

PURPOSE: To study central corneal endothelial cell density and morphology and corneal topography in transplanted corneas for keratoconus 10 to 17 years postoperatively. METHODS: Retrospective, noncomparative case series including all keratoconus patients who underwent penetrating keratoplasty by one surgeon, at the same center, between January 1986 and December 1994. Seventeen patients (22 eyes) met the criteria. Four patients (5 eyes) with unchanged visual acuity during the follow-up period did not agree to return for the last follow-up examination, 1 patient (1 eye) had graft failure, and 3 patients (4 eyes) were lost to follow-up. We reviewed the charts of 9 patients (12 eyes), and collected data including manifest refraction, best corrected visual acuity (BCVA), endothelial cell density, cell morphology, and corneal topography. RESULTS: The mean follow-up period for all eyes evaluated was 13.3 +/- 2.4 years (range 10-17 years). At the last follow-up, 91.7% of eyes achieved BCVA of 20/40 or better, and mean endothelial cell density was 695 +/- 113.6 cells/mm(2). Pleomorphism was detected in 5 eyes. Keratoconus pattern, by corneal topography, was not detected in any eye at the final examination. CONCLUSION: Endothelial cell count 10-17 years post-PKP for keratoconus is very low with pleomorphism and viable grafts, indicating continued endothelial instability.