Update on pediatric corneal diseases and keratoplasty

Managing pediatric corneal disorders is challenging as the prognosis of pediatric keratoplasty depends on several factors. Advancements in the genetic basis of congenital corneal diseases and investigations in congenital corneal conditions provide a better understanding of pediatric corneal conditions. Surgeons performing keratoplasty in children now have a choice of various techniques. Evolving surgical techniques of anterior lamellar and endothelial keratoplasties have expanded the management interventions in these pediatric corneal morbidity conditions; however, considerable concerns still exist in association with corneal transplantation in infants and children. Outcomes in pediatric keratoplasty depend upon the preoperative indications, the timing of surgical intervention, intraoperative and postoperative factors including the patient/care givers’ compliance. Factors such as low scleral rigidity, higher rate of graft failure, need for frequent examinations under anesthesia, and difficulty in optimal visual acuity assessment still remain a considerable challenge in pediatric scenarios. In children, deprivation amblyopia as a result of the corneal opacification can adversely affect visual development, causing dense amblyopia. Outcomes to surgical interventions for management of corneal opacification in children are further compromised by the preexisting amblyopia apart from the concerns of refractive outcome of the graft. Graft rejection, graft infection, amblyopia, and glaucoma continue to be serious concerns. In recent years both anterior and posterior lamellar keratoplasty techniques are being increasingly performed in pediatric eyes, which offer advantages in the form of lower risk of graft rejection. The timing of surgery, careful case selection, cautious intraoperative approach, and optimal postoperative management can improve the anatomical and functional outcome in difficult cases.     

Investigation of factors associated with ABCB5-positive limbal stem cell isolation yields from human donors

PurposeTo identify factors associated with isolation yields of ATP-binding cassette (ABC) superfamily member B5 (ABCB5)-positive limbal stem cells (LSCs) from human cadaveric donor eyes.MethodsWhole eye globes were obtained from the Saving Sight eye bank, Kansas City, MO and the CorneaGen eye bank, Seattle, WA. ABCB5-positive LSCs were sorted by flow cytometry upon anti-ABCB5 monoclonal antibody staining within one week after donor death. The yields of live limbal epithelial cells in their entirety and of isolated pure ABCB5-positive LSC subsets were correlated with variables contained in the eye donors’ medical information.ResultsThe mean isolation yield of live limbal epithelial cells and ABCB5-positive LSCs per donor eye was (340,000 ± 160,000 and 2,608 ± 1,842 respectively, mean ± SD). Stepwise regression analysis showed that cardiac disease-related death was the strongest negative predictor of the ABCB5-positive LSC isolation yield (p = 0.01). While we observed a trend for an age-related decline in the yield of ABCB5-positive LSCs, a statistically significant association could not be established (2% decrease/year, p = 0.11). Additionally, despite a trend for decreased isolation yields of total live limbal epithelial cells isolated from single donors with a longer time between death and tissue processing (p = 0.04), this did not affect the yields of purified ABCB5-positive LSC, which was independent of increasing time between death and tissue processing (p = 0.50).ConclusionsOur study identifies cardiac disease-related death as a donor variable significantly associated with lower ABCB5-positive LSC isolation yields.     

翼状胬肉切除联合角膜缘干细胞滑行移植治疗早期翼状胬肉

目的：探讨翼状胬肉治疗方法及时机。方法对81例早期翼状胬肉患者，先切除胬肉，再在角膜上、下缘做带有角膜缘干细胞的结膜瓣，滑行移植。结果术后局部反应轻，随访6～24个月，无1例复发。结论翼状胬肉切除联合角膜缘干细胞滑行移植是一种治疗早期翼状胬肉的安全简便有效的手术方式，美容效果可靠。     

Impact of fibrin glue versus suture closure on double-headed pterygia in Asian eyes – a 7-year study in a tertiary institution

BackgroundTo compare the recurrence rate and outcomes of double-headed pterygia using fibrin glue versus suture closure of conjunctival autograft.MethodsAll patients with double-headed pterygia who underwent pterygia excision with conjunctival autograft from January 2012 to January 2019 in the National University Hospital of Singapore were included. Patients were divided into 2 groups depending on whether fibrin glue or sutures were used to secure the conjunctival autograft in place. All patients had a minimum of 6 months follow-up.ResultsA total (26 patients) of 22 eyes had fibrin glue, while eight eyes underwent suture closure of their conjunctival autograft. Fibrin glue group had 4.5% recurrence rate, while suture group had 37.5% recurrence rate (p = .021). There is statistically significant improvement for overall visual acuity (p = .009) and cylinder (p = .002). There is also statistically significant improvement for visual acuity in the glue group (p = .026), but not in the suture group. Fibrin glue group had a shorter operation duration time compared to suture group (p < .001).There were no cases of graft dislocation, contraction or limbal stem cell deficiency.ConclusionsLow recurrence rates and good postoperative visual outcomes can be achieved with the split conjunctival autograft technique. Our study suggests that fibrin glue has an additional benefit over the use of sutures in the management of these complex cases.     

两种不同缝线方法治疗原发性翼状胬肉的疗效比较

目的：观察2种不同缝线方法治疗原发性翼状胬肉的临床疗效。方法：前瞻性研究。选取2015年4月 至2018年4月于解放军乌鲁木齐市第474医院住院并手术的翼状胬肉患者128例(128眼)，采用随机数字表法随机分成观察组和对照组，每组64例（64眼）。观察组采用翼状胬肉切除联合连续缝合自体结膜瓣移植治疗，对照组采用翼状胬肉切除联合间断缝合自体结膜瓣移植治疗。观察2组术后1、3、 7 d的疼痛、角膜刺激症状程度；角膜荧光染色确定2组角膜上皮完全愈合时间；6个月随访中记录结膜完全愈合、瘢痕纤维增生及胬肉复发情况。2组间各指标的比较采用独立样本t检验；2组间率的比 较采用卡方检验（必要时辅以Fisher精确概率法直接计算P值）。结果：疼痛和刺激症状评分方面，观察组术后1 d和3 d均低于对照组（疼痛评分：t=-40.477，P<0.001；t=-23.376，P<0.001。刺激症状评分： t=-18.431，P<0.001；t=-7.894，P<0.001)，术前和术后7 d，2组间差异无统计学意义。角膜荧光染色 显示角膜上皮完全愈合率方面，观察组术后3 d和5 d均高于对照组（χ2 =4.354，P=0.037；χ2 =13.333， P<0.001），术后7 d组间差异无统计学意义。观察组的痊愈率高于对照组（χ2 =8.848，P=0.003），观察 组的瘢痕痊愈率低于对照组（χ2 =8.214，P=0.004），2组胬肉复发率差异无统计学意义。观察组拆线 时间早于对照组（t=-32.686，P<0.001），拆线耗时短于对照组（t=-20.236，P<0.001），拆线疼痛评分低于对照组（t=-26.580，P<0.001），差异均有统计学意义。结论：翼状胬肉切除联合连续缝合自体结膜瓣移植治疗原发性翼状胬肉，术后眼部疼痛、刺激、炎症反应轻，角膜上皮愈合更快，可明显减少瘢痕的形成，术后拆线更早，拆线耗时短且疼痛感较轻。     

Factors impacting long-term pulmonary autograft durability after the Ross procedure

Objective

Although the Ross procedure provides excellent long-term survival and a high quality of life, its use has been limited to relatively few centers. In this study, we evaluated long-term Ross procedure results in adults to assess the predictors of pulmonary autograft durability.

Biomarkers of in vivo limbal stem cell function

PurposeTo evaluate in vivo parameters as biomarkers of limbal stem cell function and to establish an objective system that detects and stage limbal stem cell deficiency (LSCD).MethodsA total of 126 patients (172 eyes) with LSCD and 67 normal subjects (99 eyes) were included in this observational cross-sectional comparative study. Slit-lamp biomicroscopy, in vivo laser scanning confocal microscopy (IVCM), and anterior segment optical coherence tomography (AS-OCT) were performed to obtain the following: clinical score, cell morphology score, basal cell density (BCD), central corneal epithelial thickness (CET), limbal epithelial thickness (LET), total corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and tortuosity coefficient. Their potential correlations with the severity of LSCD were investigated, and cutoff values were determined.ResultsAn increase clinical score correlated with a decrease in central cornea BCD, limbal BCD, CET, mean LET, maximum LET, CNFL, CNFD, CNBD, and tortuosity coefficient. Regression analyses showed that central cornea BCD, CET and CNFL were the best parameters to differentiate LSCD from normal eyes (Coef = 3.123, 3.379, and 2.223; all p < 0.05). The rank correlation analysis showed a similar outcome between the clinical scores and the central cornea BCD (ρ = 0.79), CET (ρ = 0.82), and CNFL (ρ = 0.71). A comprehensive LSCD grading formula based on a combination of these parameters was established.ConclusionsA comprehensive staging system combining clinical presentation, central cornea BCD, CET, and CNFL is established to accurately and objectively diagnose LSCD and stage its severity.     

改良带角膜缘干细胞的游离结膜瓣移植术治疗翼状胬肉

目的:探讨改良带角膜缘干细胞的游离结膜瓣移植术治疗翼状胬肉的临床疗效及对泪膜功能的影响。方法:病例对照研究。将我院2017-03/2021-03收治的60例60眼翼状胬肉患者,按随机数字表法分为对照组和观察组,各30例30眼,对照组给予翼状胬肉切除联合羊膜移植术治疗,观察组给予翼状胬肉切除联合改良带角膜缘干细胞的游离结膜瓣移植术治疗,治疗周期均为21d。比较两组患者临床疗效、手术时间、角膜创面修复时间,术前和术后1、3mo的干眼评分、泪膜破裂时间值和基础泪液分泌试验值以及不良反应发生情况。结果:观察组临床治疗总有效率高于对照组(χ²=5.963,P=0.015),观察组手术时间长于对照组(t=-2.643,P<0.05),角膜创面修复时间短于对照组(t=2.182,P<0.05)。两组患者在术后1、3mo,干眼评分与术前比较均下降(均P<0.05),且观察组与对照组比较有差异(t=2.082、3.956,均P<0.05)。术后1、3mo泪膜破裂时间与术前比较均升高(均P<0.05),且观察组与对照组比较有差异(t=4.245、2.070,均P<0.05);术后1、3mo基础泪液分泌试验值与术前比较均升高(均P<0.05),且观察组与对照组比较有差异(t=2.076、2.223,均P<0.05)。两组患者的并发症发生率比较差异无统计学意义(P=0.572)。结论:改良带角膜缘干细胞的游离结膜瓣移植术可有效改善翼状胬肉患者临床症状,改善泪膜功能,利于术后角膜创面修复,不良反应发生率较低。