角膜移植的研究进展

角膜移植是用透明、健康的供体角膜组织替换混浊病变的角膜组织,使患者复明或控制角膜病变,达到增进视力或治疗某些角膜疾病的眼科治疗方法.传统角膜移植分为穿透性角膜移植和板层角膜移植.近10a,深板层角膜移植和内皮细胞移植手术逐渐崛起.而目前,人工角膜移植手术的发展为不适合传统穿透性角膜移植手术的患者提供一种新的选择.本文综述了目前角膜移植领域手术技术的适应证、术后并发症等.     

Identifying causes for poor visual outcome after DSEK/DSAEK following secondary DMEK in the same eye

Purpose: To identify causes of reduced visual acuity after Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) and to determine whether such eyes can be successfully ‘repaired’ with a secondary Descemet membrane endothelial keratoplasty (DMEK). Methods: Twelve eyes of 12 patients, who underwent secondary DMEK to manage poor visual outcome after initial DSEK/DSAEK, were evaluated with biomicroscopy, Pentacam imaging, and specular and confocal microscopy, before and at 1, 3 and 6 months after DMEK. Results: Four causes of reduced optical quality of the transplanted host cornea could be identified in DSEK/DSAEK: five eyes (42%) showed large host‐Descemet remnants within the visual axis during surgery; six eyes (50%) irregular graft thickness; six eyes subtle ‘stromal waves’; and nine eyes (75%) high reflectivity at the donor‐to‐host interface. After DMEK graft replacement, all corneas cleared and achieved a best corrected visual acuity of ≥20/25 (≥0.8), except for one with a partial Descemet graft detachment. Pachymetry values decreased from 670 (±112) μm before to 517 (±57) μm after secondary DMEK. Higher‐order aberrations (Coma and Trefoil) at the posterior surface tended to be lower (p = 0.07) in DMEK grafts than in DSEK/DSAEK grafts. Conclusion: Host‐Descemet remnants at the donor‐to‐host interface, interface reflectivity, graft thickness irregularity and donor stromal contraction may contribute to poor visual outcome after DSEK/DSAEK, without causing permanent host corneal damage, as in most cases, complete visual recovery could be achieved by performing a secondary DMEK.     

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.     

Effect of the position of the corneal lamella on the frequency of its detachment

AIM: To determine the influence of gaps [places where neither the donor’s nor the recipient’s Descemet’s membrane (DM) is present] and overlaps (places where the recipient’s DM is covered by the donor’s DM) on the frequency of postoperative detachment of DM endothelial keratoplasty (DMEK) lamellae.METHODS: Totally 64 eyes of 64 patients with Fuchs’ endothelial dystrophy or bullous keratopathy indicated for DMEK were randomly divided in two groups. The diameter of the implanted DMEK lamella was the same in both groups (8 mm), but we changed the diameter of the removed recipient DM. In the first group (32 eyes), the circular area was approximately 8.5 mm (gaps); in the second group (32 eyes), the diameter was 7.5 mm (overlaps). Postoperatively we noted all cases of detachment visible on the slit lamp and these cases we indicated for rebubbling. We also measured the uncorrected distance visual acuity (UDVA) as well as corrected distance visual acuity (CDVA) in decimal and postoperative endothelial cell density (ECD). The minimum follow-up time was 6mo.RESULTS: The number of rebubbling procedures in the entire group of patients was 13, i.e., 20.3%, with 6 eyes (18.7%) in the gap group, and 7 eyes (21.9%) in the overlap group. Lamella replacement (re-DMEK) was required in 3 (gap group) and 2 patients (overlap group), respectively. The difference between the groups was statistically insignificant. The UDVA was 0.54±0.21 in the gap group and 0.58±0.24 in the overlap group. The CDVA was 0.74±0.22 and 0.80±0.16, respectively. ECD was 1920±491 and 2149±570 cells/mm2. The small differences between both groups were not statistically significant.CONCLUSION: We do not notice any difference in the group of patients with overlaps or gaps of DM. The presence of small areas of gaps or overlaps does not affect the frequency of detachment of the DMEK lamellae.     

选择性角膜内皮移植术

长期以来,治疗角膜内皮病变标准的方法为穿透性角膜移植术(PK)。虽然总体上说,PK手术成功率高,但由于术后视力恢复时间长,且可出现多种并发症,如高度散光／不规则散光、植片排斥反应以及与缝线和切口愈合相关的并发症等,因此并非一种理想的手术方式。过去十几年内,出现了多种选择性角膜内皮移植术,如经角膜瓣途径的内皮移植术、经角巩膜袋途径的内皮移植术及带活性内皮细胞的Descemet’s膜移植术等。与PK手术相比,这些新的手术方法理论：有着多方面的优势,初步的临床结果亦令人鼓舞,有可能成为替代传统PK手术治疗角膜内皮病变的更有效的方法。     

Simultaneous tectonic Descemet stripping endothelial keratoplasty and tectonic Bowman layer transplant for the management of corneal perforation

AIM: To report the outcomes of three cases of corneal perforation managed with simultaneous tectonic Descemet stripping endothelial keratoplasty (t-DSEK) and tectonic Bowman layer transplant (t-BLT) as an alternative to tectonic penetrating keratoplasty (t-PKP).METHODS: Three eyes of three patients receiving simultaneous t-DSEK and t-BLT for corneal perforation were included. The technique for DSEK was modified depending on individual requirements. The t-BLT technique was standardised using an 8 mm graft and fixated with a running suture. Success was measured by the ability of this procedure to close a corneal perforation.RESULTS: All three cases achieved tectonic eye globe restoration and remained stable during the minimum 3-month observation period. Reinterventions were relatively common: 2 cases required amniotic membrane transplant for persistent epithelial defects. One case required DSEK rebubbling. One case developed angle closure glaucoma requiring surgical peripheral iridectomy.CONCLUSION: Simultaneous t-DSEK and t-BLT may be a useful strategy for the management of corneal perforation as an alternative management to t-PKP for selected cases.     

【In Press】 Descemet stripping automated endothelial keratoplasty in phakic eyes: incision modification reducing cataract formation

AIM: To evaluate the efficacy of a technical modification to reduce the incidence of traumatic cataract induced by Descemet stripping automated endothelial keratoplasty (DSAEK) performed in phakic eyes. METHODS: A retrospective cohort study. The records of all patients with a clear crystalline lens and endothelial failure that underwent modified DSAEK at our insitution were reviewed. In this modification, in order to avoid inadvertent touch of the insertion forceps against the exposed crystalline lens while passing across the anterior chamber, the incision sites were shifted from the standard 9 and 3 o’clock positions, superiorly to the 10 and 2 o’clock position respectively. Formation of typically traumatic, anterior subcapsular cataract in these patients was compared to that observed in a cohort including all the patients with a clear crystalline lens and endothelial failure that underwent conventional DSAEK at our institution. RESULTS: The study group included 49 eyes following modified DSAEK and the control group included 35 eyes following DSAEK with conventional incision sites. Anterior subcapsular cataract occurring 4 mo or less postoperatively was identified in 2 of 49 (4%) eyes in the study group and 7 of 35 (20%) eyes in the control group. The rates of traumatic cataract were significantly higher in the control group in comparison to the study group (P=0.03, RR=4.9, 95%CI 1.08-22.1). CONCLUSION: Traumatic cataract formation following phakic DSAEK may be avoided with a simple modification to the position of the incision sites.     

Descemet stripping automated endothelial keratoplasty in phakic eyes: incision modification reducing cataract formation

AIM: To evaluate the efficacy of a technical modification to reduce the incidence of traumatic cataract induced by Descemet stripping automated endothelial keratoplasty (DSAEK) performed in phakic eyes. METHODS: A retrospective cohort study. The records of all patients with a clear crystalline lens and endothelial failure that underwent modified DSAEK at our insitution were reviewed. In this modification, in order to avoid inadvertent touch of the insertion forceps against the exposed crystalline lens while passing across the anterior chamber, the incision sites were shifted from the standard 9 and 3 o’clock positions, superiorly to the 10 and 2 o’clock position respectively. Formation of typically traumatic, anterior subcapsular cataract in these patients was compared to that observed in a cohort including all the patients with a clear crystalline lens and endothelial failure that underwent conventional DSAEK at our institution. RESULTS: The study group included 49 eyes following modified DSAEK and the control group included 35 eyes following DSAEK with conventional incision sites. Anterior subcapsular cataract occurring 4mo or less postoperatively was identified in 2 of 49 (4%) eyes in the study group and 7 of 35 (20%) eyes in the control group. The rates of traumatic cataract were significantly higher in the control group in comparison to the study group (P=0.03, RR=4.9, 95%CI 1.08-22.1). CONCLUSION: Traumatic cataract formation following phakic DSAEK may be avoided with a simple modification to the position of the incision sites.     

Surgery for glaucoma in modern corneal graft procedures

Glaucoma is a common cause of vision loss after corneal transplantion and is considered a major risk factor for graft failure. Glaucoma may be present before corneal transplant surgery, or increased intraocular pressure may develop after keratoplasty in up to one-third of patients. Pre-existing glaucoma should be controlled before keratoplasty, either medically or surgically. For postkeratoplasty increase in intraocular pressure; identifying the risk factors allows appropiate follow-up and management. Patients undergoing anterior lamellar keratoplasty may take advantage of reduced rates of postkeratoplasty glaucoma. Glaucoma also complicates eyes with endothelial keratoplasties, mostly related to management of intraocular pressure spikes derived from anterior chamber air bubbles. Nevertheless, the severity is less, and the intraocular pressure is more easily controlled when compared with penetrating keratoplasty. Adequate management of glaucoma that develops before or after keratoplasty may save eyes from irreversible damage to the optic nerve and increase graft survival.     

角膜移植术式的重大变化趋势

角膜移植手术是治疗多种角膜疾病的有效方法，有时是唯一方法。能否正确选择手术时机和手术方式，对于治疗效果至关重要。因手术技术的改进、对感染性角膜病较早采用板层角膜移植且疗效肯定、对穿透性角膜移植术后植片慢性失功等问题的发现、研究和认识，以及免疫排斥反应仍是角膜移植早期失败的主要原因，所以传统观念上穿透性角膜移植和板层角膜移植的适应证发生巨大变化，对传统的适应证提出了新的挑战。     

A Comparison of Posterior Lamellar Keratoplasty Modalities: DLEK vs. DSEK

Purpose

To compare clinical outcomes after deep lamellar endothelial keratoplasty (DLEK) with Descemet stripping endothelial keratoplasty (DSEK) performed as initial cases by a single surgeon.

Methods

Sixteen patients with corneal endothelial were enrolled. Eight patients (8 eyes) underwent DLEK and 8 patients (8 eyes) DSEK. We measured uncorrected visual acuity, best corrected visual acuity (BCVA), manifest refraction, corneal endothelial count, interface opacity via Schiempflug imaging, and contrast sensitivity, as well as tracked postoperative complications over the first postoperative year.

Results

Primary graft failure occurred in two DLEK cases and one DSEK case, all of which were excluded for further analysis. The average 12-month postoperative BCVA was 20/70 in the DLEK group and 20/50 in the DSEK group, with the difference not statistically significant. No significant differences were identified between the 2 groups in terms of mean spherical equivalent and refractive astigmatism, although individuals in the DSEK group tended toward hyperopia. The average endothelial cell count at postoperative month 12 was 1849±494 in the DLEK group and 1643±417 cells/mm² in the DSEK group, representing cell losses of 26.2% and 31.9%, respectively. No significant differences in endothelial cell count or endothelial cell loss were observed between groups. Early postoperative donor disc dislocation occurred in two eyes after DLEK and one eye after DSEK. Interface opacities and contrast sensitivities were similarly not significantly different between groups.

Conclusions

No significant differences in any assessed clinical outcome were observed between individuals undergoing DLEK and DSEK, when performed as initial cases by a single surgeon.     

Comparison of penetrating and endothelial keratoplasty in patients with iridocorneal endothelial syndrome: A registry study

Background

To compare graft survival of endothelial keratoplasty (EK) versus penetrating keratoplasty (PK) in patients with iridocorneal endothelial (ICE) syndrome and identify ocular features associated with graft survival.

Methods

Observational, prospective, cohort study. A total of 30 806 first grafts performed between 1985 and 2020 were identified through the Australian Corneal Graft Registry and included in this observational, prospective cohort study. A total of 196 eyes underwent a primary corneal graft for ICE syndrome. Kaplan–Meier graft survival plots and Chi-squared tests were performed to identify graft survival rates for EK and PK. A history of raised intraocular pressure (IOP) was also recorded and analysed. Graft survival of eyes with ICE syndrome were compared to that of other indications.

Results

Grafts performed for ICE syndrome increased to 0.8% of all cases during the 2005 to 2020 period compared with 0.5% between 1985 to 2004 (χ²=9.35, p = 0.002). From 2010, EK surpassed PK as the preferred graft type. Survival of primary grafts in eyes with ICE syndrome was lower than for other indications (log-rank = 56.62, p < 0.001). Graft survival was higher following PK than Descemet stripping (automated) endothelial keratoplasty (DS(A)EK) (log-rank = 10.56, p = 0.001). Graft survival was higher in eyes without a history of raised IOP compared to those with a reported history of raised IOP (log-rank = 13.06, p < 0.001).

Conclusions

ICE syndrome carries a poor prognosis for graft survival. DS(A)EK had a poorer prognosis than PK. A history of raised IOP is associated with higher risk of graft failure.     

部分板层角膜移植联合层问羊膜移植治疗角膜穿孔

目的 探讨层间羊膜移植联合部分板层角膜移植治疗角膜溃疡穿孔的临床疗效。方法对4例角膜溃疡穿孔患者,行角膜溃疡板层切除、层间羊膜移植联合部分板层角膜移植术。术后利用共焦显微镜和裂隙灯显微镜进行观察,随访1～7个月。结果术后3例裸眼视力得到提高,1例裸眼视力下降,但所有病例的矫正视力都有提高。未见双前房、免疫排斥反应等并发症。结论该手术是一种有效的治疗周边角膜穿孔的方法。     

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.     

不同病因对角膜内皮移植术后视力的影响

背景 角膜后弹力层剥除联合自动角膜刀取材内皮移植术（DSAEK）是目前治疗角膜内皮失代偿的首选术式,但不同角膜病变患者术后视力恢复情况国内外的报道有所不同. 目的 比较不同病因所致角膜内皮失代偿患者DSAEK术后视功能的恢复情况,评价不同角膜病变对DSAEK术后视力的影响. 方法 回顾性分析2007年12月至2009年12月在北京大学第三医院眼科就诊的角膜内皮失代偿患者67例71眼的临床资料,根据原发病因的不同将其分为Fuchs角膜内皮营养不良组19例22眼、白内障术后大泡性角膜病变组36例37眼及其他因素引起的角膜内皮失代偿者（其他病因组）12例12眼,所有患眼均行DSAEK,分析其术后第1、3、7、30、90、180天各组术眼视力改善情况,采用SPSS 16.0统计学软件的x2检验和重复测量两因素方差分析对各组术眼手术前后不同视力的眼数分布及不同病因组在不同时间点LogMAR视力的差异进行比较. 结果 入选的71眼中,71.83％的患眼术前视力低于0.1,所有患眼视力均低于0.3.术前Fuchs角膜内皮营养不良组、白内障术后大泡性角膜病变组和其他病因组总体比较视力差异无统计学意义（x2=3.427,P＞0.05）.术后第1 80天,Fuchs角膜内皮营养不良组视力≥0.8者5眼,占22.73％,略高于白内障术后大泡性角膜病变组的10.81％和其他病因组的8.33％,但3个组间不同视力的眼数分布差异无统计学意义（x2=0.330,P＞0.05）.3个组患眼随着术后时间的延长,LogMAR视力值逐渐下降,差异有统计学意义（F时间=88.000,P＜0.01）;术后第7天,白内障术后大泡性角膜病变组LogMAR视力值为1.29±177;0.57,明显高于Fuchs角膜内皮营养不良组的0.82±177;0.43和其他病因组的0.91±177;0.39,差异均有统计学意义（P＜0.05）;术后第90天,Fuchs角膜内皮营养不良组LogMAR视力值为0.40±177;0.28,明显低于白内障术后大泡性角膜病变组的0.64±177;0.44和其他病因组的0.73±177;0.54,差异均有统计学意义（P＜0.05）;而术后第180天,3个组间LogMAR视力值的差异均无统计学意义（P＞0.05）.Fuchs角膜内皮营养不良组视力在术后3个月时达稳定,白内障术后大泡性角膜病变组和其他病因组术后90～ 180 d视力仍有变化. 结论 DSAEK是治疗各种角膜内皮失代偿的有效方法,Fuchs角膜内皮营养不良、白内障术后大泡性角膜病变和其他病因引起的角膜病变行DSAEK术后6个月视力均恢复较好,但Fuchs角膜内皮营养不良患者术后视力恢复更快.     

Phacoemulsification in eyes with corneal opacities after deep anterior lamellar keratoplasty

To evaluate the maneuverability and efficacy of phacoemulsification and intraocular lens (IOL) implantation in eyes with corneal opacities after deep anterior lamellar keratoplasty (DALK), twelve eyes of 12 patients with mild to moderate corneal opacities after DALK and coexisting cataracts were analyzed retrospectively. Phacoemulsification and IOL implantation assisted with anterior capsule staining, as well as non-invasive optical fiber illumination, were performed on all eyes. No intraoperative or postoperative complications were noted. Mean corrected distance visual acuity (logMAR) improved from 1.24±0.17 to 0.73±0.22. Post-phaco intraocular pressure was maintained between 13 to 20 mm Hg in all cases throughout the follow-up period. Mean endothelial cell density decreased from 2258.42±205.94 to 1906.25±174.23 cells/mm2. Phacoemulsification and IOL implantation are safe and valid in eyes with mild to moderate corneal opacities after DALK and coexisting cataracts when assisted with anterior capsule staining and non-invasive optical fiber illumination.     

Demographic and clinical profile,surgical outcome,and quality of life in patients who underwent bilateral lamellar corneal grafts

Purpose:Lamellar corneal grafts have revolutionized the management of corneal blindness by replacing only the disease specific corneal layers. To the best of our knowledge, there is no study in literature describing the outcomes of bilateral lamellar keratoplasty in the Indian population. The aim of this work was to study the demographic profile, surgical outcomes, and quality of life in patients who underwent bilateral lamellar keratoplasty and to assess the correlation between these three.Methods:An observational cross-sectional study was conducted on 47 patients who underwent bilateral deep anterior lamellar keratoplasty (DALK) (n = 31) or descemet stripping automated endothelial keratoplasty (DSAEK) (n = 16) with a minimum follow-up of 6 months after the second surgery. Demographic parameters were collected by interview, surgical outcomes by clinical examination, and quality of life by a questionnaire.Results:A total of 47 patients were evaluated, women 42.56%, (n = 20) and men 57.44% (n = 27) with 38.3% being in 18–30 years age group and 23.4% above 60 years; 17.02% patients had a good socioeconomic status (score >60) and 61.70% had poorer socioeconomic status (score <50). Quality of life score (VR-QoL) was ≥50 in 82.9% patients and ≥70 in 14.89%. No significant association existed between VR-QoL scores and demographic factors. However, statistically significant association existed between VR-QoL and age of patient (P < 0.05), postoperative vision (P ≤ 0.05), and contrast sensitivity (P ≤ 0.01).Conclusion:Bilateral lamellar corneal grafts provide satisfactory visual outcomes compatible with day-to-day functioning. VR-QoL has a direct correlation to the age, visual acuity, contrast sensitivity, and inverse correlation with lenticule thickness in DSAEK and residual bed thickness in DALK.