Femtosecond laser-assisted deep anterior lamellar keratoplasty in phototherapeutic keratectomy versus the big-bubble technique in keratoconus

AIM：To compare the functional and anatomic results of femtosecond laser（FSL）-assisted deep anterior lamellar keratoplasty（DALK） associated with phototherapeutic keratectomy（PTK） and FSL-assisted DALK performed using the big-bubble technique in keratoconus.METHODS：During the first phase of the study,an electron microscopy histopathology pilot study was conducted that included four unsuitable donor corneas divided into two groups：in FSL group,FSL lamellar cuts were performed on two corneas and in FSL＋PTK group,PTK was performed at the stromal beds of two corneas after FSL lamellar cuts were made.During the second phase of the study,a randomized clinical trial was conducted that included two treatment groups of patients with keratoconus：group 1（n=14 eyes） underwent FSL-assisted DALK associated with PTK and group 2（n=12 eyes） underwent FSL-assisted DALK associated with the bigbubble technique.The main outcome measures were the postoperative visual acuity（VA） and optical coherence tomography（OCT） measurements,confocal microscopic findings,and contrast sensitivity.RESULTS：In the pilot study,histopathology showed a more regular stromal bed in the FSL＋PTK group.In the clinical trial,group 1 had significantly worse best spectaclecorrected VA and contrast sensitivity（P〈0.05 for both comparisons）.The residual stromal bed measured by OCT was significantly（P〈0.05） thicker in group 1.Confocal microscopy detected opacities only at the donor-receptor interface in group 1.CONCLUSION：Patients with keratoconus treated with FSL-assisted DALK performed using the big-bubble technique fare better than treated with FSL-assisted DALK associated with PTK.

Use of a handheld slit beam intraoperatively to assist in big bubble formation during deep anterior lamellar keratoplasty

Deep anterior lamellar keratoplasty(DALK)is preferred over conventional penetrating keratoplasty(PKP)for the treatment of anterior corneal opacities or ectasias due to decreased risk of endothelial rejection.However,DALK remains surgically challenging,largely due to challenges associated with achieving consistent pneumo-dissection of posterior stroma from the underlying pre-Descemet’s or Descemet’s membrane(DM).Air must be injected at sufficient depth in the corneal stroma in order to achieve successful pneumo-dissection,but advancing a needle too deep into the cornea can lead to perforation of DM.We describe here a novel technique using a handheld slit lamp(Eidolon model 510L,Eidolon Optical LLC,Natick,MA,USA)to assist in creation of the big-bubble in DALK surgery.Use of a handheld slit beam intraoperatively is a safe,relatively inexpensive,and effective technique for increasing the success of big-bubble formation in DALK procedures.

Comparison of long-term results after manual and femtosecond assisted corneal trephination in deep anterior lamellar keratoplasty for keratoconus

AIM: To compare long-term postoperative outcomes of manual and femtosecond assisted corneal trephination in deep anterior lamellar keratoplasty(FS-DALK) for keratoconus.METHODS: In the retrospective study, 17 consecutive eyes that underwent vertical side cut incision FS-DALK and 22 eyes that underwent trephine incision DALK were collected over a 2-year period. Main measurements included postoperative uncorrected-visual acuity(UCVA), corrected distance visual acuity(CDVA), refractive sphere and cylinder, manifest refraction spherical equivalent(MRSE), flat and steep corneal keratometry(K1 and K2), endothelial cell density(ECD), and time of epithelium healing and suture removal.RESULTS: Groups were comparable for diagnosis and preoperative visual acuity. Follow-up averaged 23 mo(range, 12-36 mo). At 12 mo, the mean UCVA was better in the manual-DALK group(P=0.039), and the refractive sphere was lower in the FS-DALK group(P=0.040). MRSE between groups differed at 1, 6, and 12 mo postoperatively(P=0.047, 0.025, 0.042, respectively). Mean CDVA, cylinder, K1, K2,corneal astigmatism, ECD, and time of epithelium healing were similar between groups. Stability of MRSE, ECD, and K1 returned sooner after FS-DALK. Initial loosened suture removal time was earlier in the manual-DALK group(P=0.042) while complete suture removal time was similar(P=0.122).CONCLUSION: Manual and femtosecond assisted corneal trephination in DALK are options for advanced keratoconus. FS-DALK do not result in improved visual acuity but it is more stable during the follow-up period. FSDALK in the present form show limited benefit, so surgical design and parameters still need to be optimized and explored.

Comparison of clinical outcomes of deep anterior lamellar keratoplasty and excimer laser assisted anterior lamellar keratoplasty in keratoconus

AIM: To compare and evaluate the clinical outcomes of deep anterior lamellar keratoplasty(DALK) and excimer laser assisted anterior lamellar keratoplasty(ELLK) in eyes with keratoconus.METHODS: In this study, 57 eyes of 56 patients operated between 2013 to 2017 were included. Thirty-one eyes underwent big-bubble DALK and twenty-six eyes underwent ELLK. Preoperative and at control visits complete ophthalmic examination was performed. RESULTS: The mean patient age at the time of DALK surgery was 27 y and mean follow-up period was 21±5.4 mo. The mean patient age at the time of ELLK surgery was 27 y and mean follow-up period was 40±18 mo. Mean best spectacle corrected visual acuity(BSCVA) at postoperative period was significantly higher for DALK group(0.66±0.11) versus ELLK group(0.4±0.2)(P<0.05). Descemet's membrane microperforation was occurred in 7 patients in DALK group versus in 1 patient in ELLK group. In 4 eyes, interface irregularity was developed in ELLK group. None of the patients in follow-up had graft rejection in both groups.CONCLUSION: In ELLK group, complication rate is lower, the surgical technique is simpler, faster and safer and also ELLK requires less experience with respect to DALK. Further, DALK can be performed unless satisfactory visual acuity is achieved after ELLK.

飞秒激光辅助的深板层角膜移植与大气泡全板层角膜移植治疗圆锥角膜的远期疗效比较

目的比较飞秒激光辅助的深板层角膜移植(去除75%以上的角膜基质层)和飞秒激光联合大气泡技术(去除全部基质层,只保留后弹力层和内皮层)的全板层角膜移植治疗中晚期圆锥角膜的远期临床效果及安全性。方法回顾性病例对照分析。28例(32只眼)圆锥角膜患者9例(10只眼)行飞秒激光辅助的深板层角膜移植手术,19例(22只眼)行飞秒激光联合大气泡技术的全板层角膜移植手术。随访4年,比较最佳矫正视力、角膜散光、残留近视度数、角膜曲率、中央角膜厚度及内皮细胞丢失率在两种手术方式之间的差异。结果两种手术方式在术后最佳矫正视力、角膜散光、角膜曲率、中央角膜厚度及内皮细胞丢失率等方面无显著差异(P> 0. 05),但飞秒激光联合大气泡技术全板层角膜移植术后残留近视度数更低,与飞秒激光辅助的深板层角膜移植相比,具有显著差异(P <0. 05)。结论远期随访结果表明飞秒激光辅助的大气泡全板层角膜移植具有良好的临床效果及安全性,是治疗圆锥角膜更好的手术方式。

飞秒激光辅助的大气泡法全板层角膜移植治疗圆锥角膜及角膜瘢痕临床疗效观察

目的观察飞秒激光辅助的大气泡全板层角膜移植术治疗圆锥角膜及角膜瘢痕临床效果。方法系列病例研究。20例(23只眼)患者(圆锥角膜22只眼,角膜瘢痕1只眼)采用飞秒激光辅助的大气泡法全板层角膜移植手术。供体及受体角膜均采用500-kHz VisuMax飞秒激光进行垂直边切,平均随访时间为(53.6±5.5)个月(47~61个月)。结果术中大气泡成功形成及后弹力层清晰暴露的成功率为91.3%(21/23)。术后裸眼视力、最佳矫正视力、角膜曲率、角膜散光及角膜厚度均有改善,与术前相比差异显著(P<0.05)。结论飞秒激光辅助的大气泡法全板层角膜移植对于圆锥角膜和角膜瘢痕患者具有良好的临床效果及安全性。

改良大泡技术辅助的暴露后弹力层深板层角膜移植术(附视频)

目的探讨改良大泡技术辅助的暴露后弹力层深板层角膜移植术(DALK)手术技术及技巧,为临床顺利施行DALK提供参考。方法 2011年1月至2012年8月山东省眼科医院对37例(38只眼)角膜基质病变的患者施行大泡技术辅助的暴露后弹力层DALK。改良要点如下:(1)采用负压环钻钻切角膜深度约250μm,一次性角膜刀将前部病变的角膜基质切除;(2)30号穿刺针以10°～30°于旁中央角膜穿刺进入后角膜基质并快速注入无菌空气约1mL,然后采用45°一次性角膜刀将后部基质切除;(3)术中根据情况于角膜缘进行前房穿刺控制眼压;(4)供者角膜剥离后弹力层后覆盖于植床,10-0尼龙线间断(或连续)缝合。结果 37例患者(37只眼)成功接受了DALK,1例斑块状角膜营养不良患者(1只眼)因植床大穿孔改行穿透角膜移植术。术后8例(21.6%)患者出现双前房,1例患者因真菌再次感染行穿透角膜移植术。所有患者角膜移植片透明并与植床贴附紧密,裂隙灯检查难辨层间界面。37例患者(37只眼)最佳矫正视力由术前手动/20cm～0.05提高至术后0.1～1.0(P<0.01)。结论改良大泡技术辅助的暴露后弹力层DALK在达到有效分离后弹力层的同时,降低了术中发生后弹力层破裂的风险,临床安全有效,可扩展临床深板层角膜移植手术的适应证。

暴露后弹力层的前部深板层角膜移植手术进展

前部深板层角膜移植术（deep anterior lamellar keratoplasty,DALK）是一种新的角膜移植技术,该技术将去除后弹力层和内皮层的供体角膜移植到去除全部基质的植床上,以期望获得与穿透角膜移植术相同的光学效果,同时减少术中和术后并发症.DALK对手术技术要求高,关键步骤是暴露后弹力层.暴露后弹力层的方法经历了直接分离法、基质无菌空气辅助分离法、水分离法、黏弹剂法、大泡技术等,这些技术在不断改进且日趋成熟.DALK的优点是保留了眼球结构和免疫的相对完整性,可减少术后内皮型免疫排斥反应、角膜植片慢性功能失代偿以及角膜植片因外伤哆开的风险.本文就DALK的适应证、手术技术和并发症等进行综述,为其技术改进和广泛临床应用提供思路.

大气泡技术联合湿剥法深板层角膜移植术

目的：介绍大气泡技术联合湿剥法深板层角膜移植术。方法：选择2016年1月至2017年6月期间在温州医科大学附属眼视光医院因单纯疱疹病毒性角膜炎（HSK）拟行大气泡技术联合湿剥法深板层角膜移植术患者59例（59眼）。术中行大气泡技术联合深板层角膜移植时，如遇2型大气泡或小气泡，改湿剥法完成手术。结果：59眼均成功行深板层角膜移植术，无一例出现术中微穿孔，术中2型大气泡占71％。结论：HSK患者术中可出现高比例2型大气泡，出现2型大气泡或小气泡改湿剥法钝性分离，保留后弹力层前膜，手术安全。