Tectonic deep anterior lamellar keratoplasty in impending corneal perforation using cryopreserved cornea

We report a case of tectonic corneal transplantation for impending corneal perforation to preserve anatomic integrity using cryopreserved donor tissue. An 82-year-old woman exhibiting impending corneal perforation suffered from moderate ocular pain in the left eye for one week. After abnormal tissues around the impending perforation area were carefully peeled away using a Crescent blade and Vannas scissors, the patient received tectonic deep anterior lamellar keratoplasty using a cryopreserved cornea stored in Optisol GS® solution at -70℃ for four weeks. At six months after surgery, the cornea remained transparent and restored the normal corneal thickness. There were no complications such as corneal haze or scars, graft rejection, recurrent corneal ulcer, and postoperative rise of intraocular pressure. Cryopreserved donor lamellar tissue is an effective substitute in emergency tectonic lamellar keratoplasty, such as impending corneal perforation and severe necrotic corneal keratitis.     

Complications in deep anterior lamellar keratoplasty – A retrospective interventional analysis in a large series

Purpose:To analyze the complications in patients managed with deep anterior lamellar keratoplasty (DALK) for diseases of the anterior corneal stroma.Methods:This is a retrospective analysis of all the patients who underwent DALK in a tertiary care center in South India from 2010 to 2020. A total of 474 eyes in 373 patients were included in the study. Patients who underwent DALK for advanced keratoconus, keratoconus with Bowman’s membrane scar, healed hydrops, macular corneal opacity, macular corneal dystrophy, granular corneal dystrophy, spheroidal degeneration, pellucid marginal degeneration, post–laser-assisted in situ keratomileusis ectasia, descematocele, post-collagen cross-linking aborted melt and dense scar, and post-radial keratotomy were included in the study. The patients were followed up for 17.2 +/- 9.2 months (1–9 years).Results:Complications noted in the surgery were intra-operatively Descemet’s membrane perforation in 31 eyes (6.54%), post-operatively secondary glaucoma in 16 eyes (3.37%), cataract in seven eyes (1.47%), suture-related complications in five eyes (1.05%), graft rejection in three eyes (0.63%), traumatic dehiscence in two eyes (0.42%), filamentary keratitis in two eyes (0.42%), interface infiltrate in one eye (0.21%), and recurrence of disease in four eyes (7.14%) out of 57 eyes with corneal dystrophy.Conclusion:DALK as an alternative to penetrating keratoplasty for anterior corneal stromal diseases. It has become an automatic choice for diseases of the anterior cornea requiring keratoplasty. Complications can occur at any stage of surgery; however, if identified and managed early, they can result in optimal outcome.     

Histopathological changes after deep anterior lamellar keratoplasty using the ‘big‐bubble technique’

Purpose: During deep anterior lamellar keratoplasty (DALK), endothelium and Descemet’s membrane are separated from the corneal stroma by intrastromal air injection (‘big‐bubble technique’). The aim of our study is to analyse histopathological changes in host corneal tissue caused by air insufflation in patients with keratoconus, their variability in 10 patients and their possible clinical implication. Methods: The excised anterior corneal lamellae of 10 patients with keratoconus having undergone DALK using the ‘big‐bubble technique’ were analysed by light and transmission electron microscopy as well as immunohistochemistry. In addition, intrastromal air accumulations were quantified morphometrically. Results: Intrastromal air was detected in all examined excised lamellae (8% of stromal volume), but with large variability (SD 8.8). It was detected preferentially in the inner layer of the corneal stroma and represented there up to 39% of the stromal volume. In addition, the air was predominantly located at one periphery of the excised lamellae. Intrastromal air bubbles were larger in the inner than in the superficial stromal layer and characterized by round shape and a CD68‐negative collagenous ‘pseudocapsule’. We detected no air‐injection‐induced alterations in Bowman’s layer and epithelium. Conclusion: Our results show that ‘big‐bubble DALK’ causes significant intrastromal air accumulations in the cornea. Pathologists should be conscious of this phenomenon and the high topographic variability. Intrastromal air in the recipient rim may be accompanied by a decrease in mechanical stability and could contribute to postoperative suture loosening.     

深板层角膜移植-一种新的光学性角膜移植技术

深板层角膜移植适合于角膜基质异常及/或混浊但内皮健康者,其恢复角膜透明性的效果与穿透性角膜移植相当。这一手术的最大优点是能避免术后排斥反应、无须内皮健康的供体。经过多年的改进,手术技术已有明显进步,但仍存在操作难度较大、费时、受体基质去除不彻底、术中后弹力膜微穿孔的缺点。随着手术技术的进一步完善,临床上相当部分的穿透性角膜移植可被深板层角膜移植取代。(眼科,2006,15:156-158)     

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.     

Big-bubble deep anterior lamellar keratoplasty for post-keratitis and post-traumatic corneal stromal scars

Background: Evaluation of outcomes of big‐bubble deep anterior lamellar keratoplasty in cases with post‐keratitis and post‐traumatic corneal scars. Design: Interventional case series. Participants: Patients with corneal stromal scarring secondary to healed infectious keratitis or trauma were recruited from the Corneal Clinic of the M. M. Joshi Eye Institute, Karnataka, India between August 2007 and December 2009. Methods: All patients underwent big‐bubble deep anterior lamellar keratoplasty surgery. Main Outcome Measures: Best‐corrected visual acuity, as well as intra‐ and postoperative complications. Results: Big‐bubble deep anterior lamellar keratoplasty was performed in 36 patients (25 males, 11 females) with post‐infectious keratitis (n = 22) and post‐traumatic (n = 14) corneal stromal scars sparing the Descemet's membrane and endothelium. Mean age was 39.7 ± 11.3 years (range: 22–58 years). Although a big bubble was achieved in all eyes (100%), intraoperative perforation of the Descemet's membrane occurred in six eyes (16%) during stromal dissection. Two cases required conversion to penetrating keratoplasty. A double anterior chamber occurred in the immediate postoperative period in three cases (8.3%). Raised intraocular pressure was seen in one eye. Mean preoperative best‐corrected visual acuity (0.03 ± 0.04) improved significantly at the end of 6 months follow‐up postoperatively (0.43 ± 0.20; P < 0.01, Wilcoxon signed‐ranks test). Corneal stromal graft rejection was noted in two cases (5.5%) during the first 3 months after surgery. Graft failure occurred in two cases (5.5%). Conclusions: Deep anterior lamellar keratoplasty using the big‐bubble technique is a viable option in cases with post‐infectious keratitis and post‐traumatic corneal stromal scarring with normal Descemet's membrane and endothelium.     

A new surgical technique for deep stromal, anterior lamellar keratoplasty

AIMS: To describe a new surgical technique for deep stromal anterior lamellar keratoplasty. METHODS: In eye bank eyes and sighted human eyes, aqueous was exchanged by air, to visualise the posterior corneal surface--that is, the "air to endothelium" interface. Through a 5.0 mm scleral incision, a deep stromal pocket was created across the cornea, using the air to endothelium interface as a reference plane for dissection depth. The pocket was filled with viscoelastic, and an anterior corneal lamella was excised. A full thickness donor button was sutured into the recipient bed after stripping its Descemet's membrane. RESULTS: In 25 consecutive human eye bank eyes, a 12% microperforation rate was found. Corneal dissection depth averaged 95.4% (SD 2.7%). Six patient eyes had uneventful surgeries; in a seventh eye, perforation of the lamellar bed occurred. All transplants cleared. Central pachymetry ranged from 0.62 to 0.73 mm. CONCLUSION: With this technique a deep stromal anterior lamellar keratoplasty can be performed with the donor to recipient interface just anterior to the posterior corneal surface. The technique has the advantage that the dissection can be completed in the event of inadvertent microperforation, or that the procedure can be aborted to perform a planned penetrating keratoplasty.     

Femtosecond laser-assisted deep anterior lamellar keratoplasty for keratoconus and keratectasia

AIM: To describe the initial outcomes and safety of femtosecond laser-assisted deep anterior lamellar keratoplasty (DALK) for keratoconus and post-LASIKkeratectasia.METHODS:In this non-comparative case series, 10 eyes of 9 patients underwent DALK procedures with a femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany). Of the 9 patients, 7 had keratoconus and 2 had post-LASIK keratectasia. A 500 kHz VisuMax femtosecond laser was used to perform corneal cuts on both donor and recipient corneas.The outcome measures were the uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal thickness, astigmatism, endothelial density count (EDC), and corneal power.RESULTS: All eyes were successfully treated. Early postoperative evaluation showed a clear graft in all cases. Intraoperative complications included one case of a small Descemet’s membrane perforation. Postoperatively, there was one case of stromal rejection, one of loosened sutures, and one of wound dehiscence. A normal corneal pattern topography and transparency were restored, UCVA and BCVA improved significantly, and astigmatism improved slightly. There was no statistically significant decrease in EDC.CONCLUSION: Our early results indicate that femtosecond laser-assisted deep anterior lamellar keratoplasty could improve UCVA and BCVA in patients with anterior corneal pathology. This approach shows promise as a safe and effective surgical choice in the treatment of keratoconus and post-LASIK keratectasia.     

飞秒激光辅助的大气泡法深板层角膜移植治疗圆锥角膜

目的评价飞秒激光辅助的大气泡法深板层角膜移植术治疗圆锥角膜临床效果及安全性。方法系列病例研究。9例（11眼）圆锥角膜患者采用飞秒激光辅助进行大气泡法深板层角膜移植手术。供体及受体角膜均采用500 kHz VisuMax飞秒激光进行垂直边切,术前超声测量角膜最薄点厚度,角膜厚度为（359.7±49.8）μm,术前UCVA为指数～0.1,术前BCVA为指数～0.12,供体直径为（7.51±0.14）mm,受体直径为（7.38±0.10）mm,随访时间为（7.70±2.88）个月。结果所有患者手术顺利,术中无并发症,术后早期所有角膜植片透明。角膜厚度为（481.4±51.3）μm,角膜地形图恢复正常形态。术后最后1次随访,UCVA为0.15～0.40,BCVA为 0.30～0.80。结论飞秒激光辅助的大气泡法深板层角膜移植对于圆锥角膜患者具有良好的临床效果及安全性。     

Reverse graft suturing to avoid Descemet’s membrane detachment of glycerol-preserved donor cornea used for therapeutic penetrating keratoplasty during COVID-19 to overcome the tissue shortage – A novel surgical technique

To overcome tissue shortage during pandemic, we switched to 100% glycerol preservation of the donor cornea, which is economical and provides longer duration of storage than the short and intermediate storage mediums we normally use like McCAREY Kaufman (MK) or cornisol. During our initial few cases of therapeutic penetrating keratoplasty using glycerol preserved donor cornea, we faced spontaneous Descemet’s detachments resistant to air tamponade. We tried reverse graft suturing and successfully reinforced Descemet’s attachment along with air tamponade, in one of the cases after multiple failed air injections. In the subsequent two cases of infective keratitis needing therapeutic penetrating Keratoplasty, we took eight reverse sutures in between the eight cardinals, to anchor the Descemet’s membrane of the graft. Both the grafts showed attached Descemet’s and maintained good graft clarity. The reverse corneal suturing technique has not been described to the best of our knowledge and hope this helps our corneal fraternity.     

Descemet membrane endothelial keratoplasty with a stromal rim in the treatment of posterior polymorphous corneal dystrophy

A 20-year-old patient, diagnosed with posterior polymorphous corneal dystrophy, developed corneal edema for which he underwent Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S) in the right eye. No intra- or postoperative complications were noted. At the last follow-up 2 years and 9 months after the procedure, the best corrected visual acuity was 1.0 and endothelial cell density declined from 3533 cells/mm 2 to 1012 cells/mm 2 . Despite the endothelial cell loss, DMEK-S appears to be a good alternative to other surgical techniques for the treatment of corneal endotheliopathies, and it may be of benefit to young patients.     

部分环状板层角膜移植治疗蚕蚀性角膜溃疡

目的 观察部分环状板层角膜移植治疗早期药物治疗无效的进展性蚕蚀性角膜溃疡的临床疗效.方法 回顾性系列病例研究.10例(11眼)常规给予局部及全身免疫抑制剂和对症治疗1周及以上、病灶不断扩散的蚕蚀性角膜溃疡患者,行部分环状板层角膜移植手术,角膜供体选自部分穿透性角膜移植术后残留的环形供体角膜.手术方法:采用7.75～8.00 mm的环钻在角膜中央压痕,在彻底切除病灶后,覆盖与病灶范围相同的供体角膜.随访6～36个月,观察患者的视力、角膜植片愈合时间及是否复发等.采用重复测量方差分析比较手术前后视力变化.结果 患者裸眼视力术后1个月平均提高(1.36±1.21)行,术后3个月平均提高(1.72±1.47)行,术后6个月平均提高(1.86±2.04)行;最佳矫正视力术后1个月平均提高(0.46±0.93)行,术后3个月平均提高(0.73±1.10)行,术后6个月平均提高(1.55±1.75)行.手术前后裸眼视力(F=5.630,P＜0.05)与最佳矫正视力(F=5.925,P＜0.05)差异均有统计学意义.术后患者角膜植片上皮平均愈合时间为(7.00±5.31)d;1例患者术后角膜植片上皮愈合不良,行羊膜移植术后20 d愈合;1例患者术后19个月复发,行二次部分板层角膜移植.所有患者随访期间未发生免疫排斥反应等并发症.结论 使用环形供体角膜的部分板层角膜移植能有效控制早期药物治疗无效的蚕蚀性角膜溃疡的发展,保存视轴区透明角膜,术后视觉效果良好,同时节约角膜供体材料.     

深板层角膜移植手术并发症及处理

目的 探讨深板层角膜移植手术的并发症及其处理.方法 回顾性病例研究.总结2005年1月至2012年2月在我科施行深板层角膜移植手术(274例)出现并发症的患者62例(62眼),分析术中和术后并发症,根据不同的并发症采用不同的处理方法.结果 术中并发后弹力层穿孔13眼;术后并发症中,双前房16眼,后弹力层皱褶13眼,继发性青光眼8眼,早期缝线松弛7眼,复发14眼,排斥4眼,角膜上皮愈合不良和基质溶解5眼,给予相应处理后均得到控制,恢复良好.结论 后弹力层穿孔和双前房是最常见的并发症.尽量减少及正确处理并发症,深板层角膜移植可以达到良好的远期效果.     

Two-year clinical outcome after Descemet membrane endothelial keratoplasty using a standardized protocol

Purpose:The purpose of this study is to evaluate 2-year clinical outcome after Descemet membrane endothelial keratoplasty (DMEK) in a variety of endothelial dysfunctions using a standardized protocol.Methods:From a group of 230 eyes which underwent DMEK for Fuchs'' endothelial corneal dystrophy (FECD), aphakic and pseudophakic bullous keratopathy, failed full thickness corneal transplants, ICE syndrome, failed DSEK, and TASS the clinical outcomes [best spectacle-corrected visual acuity (BSCVA), central endothelial cell density (ECD)] were evaluated before, and at 6, 12, and 24 months and the success rate, failure rate and postoperative complications were also analyzed.Results:Out of 230 eyes, 144 eyes (70%) had BSCVA 6/9 or better 2 years postoperatively. Mean donor ECD was 2692.23 (range, 2300–3436) cells/mm² preoperatively, which was reduced to 1433.64 (range, 619.0–2272.0) cells/mm² 2 years after DMEK surgery, indicating a mean reduction of 1258 cells/mm² (46%) in ECD.Conclusion:DMEK is a highly successful surgical procedure when following a standard protocol for treating diseases of the corneal endothelium providing a near perfect anatomic restoration and a high degree of visual rehabilitation.     

Modified deep anterior lamellar keratoplasty for the treatment of advanced keratoconus with steep corneal curvature to help in eliminating the wrinkles in the Descemet's membrane

Aims:

To determine the clinical efficacy of modified deep anterior lamellar keratoplasty (DALK) for the treatment of advanced-stage keratoconus with steep curvature.

Materials and Methods:

In this interventional, non-comparative case series, 30 patients with advanced stages of keratoconus and curvature of more than 60 D underwent a modified DALK procedure. In this technique, after big-bubble formation, posterior stromal lamella was cut and removed 5 mm centrally (baring Descemet''s membrane completely) with posterior stromal layer remaining peripherally.

Results:

The study included 30 eyes (30 patients with a mean ± SD age of 25 ± 5.4 years). The follow-up examination was performed for all participants up to 12 months after the surgery. The mean uncorrected visual acuity (UCVA) increased from 20/800 before the surgery to a subsequent 3/10 (P =0.12). Likewise, best spectacle corrected visual acuity (BSCVA) improved, reaching 6/10 postoperatively (former quantity 20/200) (P =0.18). In addition, mean keratometry and keratometric astigmatism managed to achieve considerable improvement, from 58.8 ± 5.4 D to 46.5 ± 2.1 D and 7.8 ± 2.1 to 4.54 ± 1.54 D, respectively (P =0.52). Descemet''s membrane wrinkling was not seen in any patient postoperatively.

Conclusions:

This technique is effective in restoring acceptable vision and corneal regularity in advanced cases of keratoconus with a curvature more than 60 D who are also at risk of Descemet''s membrane wrinkling after DALK. Therefore, this procedure could prevent from Descemet membrane wrinkling in such cases.     

甘油冷冻保存角膜深板层移植治疗真菌性角膜溃疡的临床研究

目的探讨甘油冷冻保存的供体角膜行深板层角膜移植术治疗浅、中层真菌性角膜溃疡的手术适应证及临床效果。方法57例（57眼）经综合抗真菌措施治疗无效的浅、中层真菌性角膜溃疡施行深板层角膜移植术,随访8～24月,观察术后复发率、视力恢复、植片透明及并发症发生情况。结果57例中,52例治愈,成功率91.23%;5例复发,复发率8.77%。矫正视力0.1～0.2者20眼,0.3～0.5者24眼,〉0.5者13眼。17例出现新生血管;13例发生排斥反应,均得到有效控制。植片全部透明。结论使用甘油冷冻保存的角膜供体行深板层角膜移植术既能及时去除病变组织,达到治疗目的,又有一定的增视效果,对药物治疗无效的浅、中层真菌性角膜溃疡是有效的手术方式。     

Preferred practice pattern and observed outcome of deep anterior lamellar keratoplasty – A survey of Indian corneal surgeons

Purpose:This study aimed to assess the preferred surgical technique and outcome of deep anterior lamellar keratoplasty (DALK) among corneal surgeons in India.Methods:An online questionnaire-based cross-sectional survey was conducted among members of the Cornea Society of India (CSI) with experience of performing >10 DALK procedure. The responses pertaining to their surgical experience, preferred technique, complications, and outcome of DALK were collected and analyzed.Results:A total of 156 responses were received. In total, 35.9% of participants reported annual keratoplasty of >50, and DALK constituted >25% surgeries for 25% of participants. Ectatic corneal disorder was reported as the most common indication for DALK by 71.6% of the respondents. Big-bubble (BB) DALK (W_A-1.82) was the most preferred technique, along with suction trephine (50%) for partial trephination and bottom port cannula (45.5%) for BB formation. On statistical analysis, no difference was observed in the surgeon reported success rate of BB formation with or without anterior lamellar keratectomy (ALK) (χ2 (1,156) = 3.1498, P = 0.08) or paracentesis (χ2 (1,156) = 0.2737, P = 0.60) before stromal air injection, and method of stromal air injection (χ2 (1,156) = 4.7325, P = 0.09). Conversion to penetrating keratoplasty was reported by 16% of participants in >25% cases, while 66.7% reported in <10% cases. Cataract and double anterior chamber were the most common complications. 50% of participants suggested that >20 procedures are required to overcome the learning curve.Conclusion:BB DALK is the most commonly practiced DALK technique, and its success is independent of ALK and paracentesis being performed prior to air injection and method of air injection (cannula/needle).     

Standardized ‘no‐touch’ donor tissue preparation for DALK and DMEK: harvesting undamaged anterior and posterior transplants from the same donor cornea

Purpose: To describe a standardized ‘no‐touch’ harvesting technique of anterior and Descemet membrane (DM) grafts for use in deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK), which provides undamaged anterior and posterior corneal grafts. Methods: A retrospective evaluation was performed of our standard method for harvesting DM grafts and DALK grafts (Technique I; n = 31) versus a newly designed ‘no‐touch’ technique (Technique II; n = 31), in which a peripheral ring of trabecular meshwork tissue is left in‐situ, and the DM graft is trephined on an underlying soft contact lens. Endothelial cell density (ECD) before and immediately after DM stripping was used as the main outcome parameter. Results: Endothelial cell density did not differ within Techniques I and II (before versus after DM stripping) (p = 0.75 and p = 0.54, respectively) or among Techniques I and II (p = 0.61). With the latter technique, anterior corneal grafts and posterior DM grafts could be harvested with negligible damage to the endothelial cell layer or the posterior stromal bed. All 93 grafts (62 DM grafts) were eligible for transplantation, and six months post‐operatively all transplants used were functional. Conclusion: The new technique offers the following advantages: (i) production of ‘undamaged’ grafts for DALK and DMEK, (ii) better controlled tissue handling of the thin DM graft during DM stripping and (iii) an increase in availability of corneal grafts obtained from the same donor tissue pool.