Generalized,severe epidermolysis bullosa simplex caused by a Keratin 5 p.E477K mutation

Epidermolysis bullosa simplex (EBS) is a skin fragility disorder resulting from mutations of structural proteins in the epidermis. We provide a brief report of long‐term survival and reproduction in a mother with EBS due to keratin 5 (KRT5) c.1429G > A (p.E477K) mutation, which causes a particularly severe form of the disease.     

Topometric and Tomographic Evaluation of Subclinical Keratoconus

ABSTRACT

Purpose

To investigate the corneal topometric and tomographic findings that can be used in the diagnosis of subclinical keratoconus.     

A Review of Machine Learning Techniques for Keratoconus Detection and Refractive Surgery Screening

ABSTRACT

Various machine learning techniques have been developed for keratoconus detection and refractive surgery screening. These techniques utilize inputs from a range of corneal imaging devices and are built with automated decision trees, support vector machines, and various types of neural networks. In general, these techniques demonstrate very good differentiation of normal and keratoconic eyes, as well as good differentiation of normal and form fruste keratoconus. However, it is difficult to directly compare these studies, as keratoconus represents a wide spectrum of disease. More importantly, no public dataset exists for research purposes. Despite these challenges, machine learning in keratoconus detection and refractive surgery screening is a burgeoning field of study, with significant potential for continued advancement as imaging devices and techniques become more sophisticated.     

The Effect of Donor- and Recipient-Related Factors on Corneal Graft Survival in Penetrating Keratoplasty

Purpose: To investigate the impact of donor and recipient factors on graft survival in penetrating keratoplasty (PK).

Material and Methods: This retrospective study included 365 eyes that underwent PK using corneas from 231 donors between June 2010 and June 2015. Patients were divided into three groups (group 1: primary endothelial diseases; group 2: iatrogenic endothelial disorders; and group 3: other pathologies with a healthy endothelium) according to PK indications. The primary outcome measure was corneal graft survival at the last visit (clear or opaque). Graft clarity was assessed using Kaplan–Meier survival analysis.

Results: The most frequent PK indication was keratoconus (KC) (20.5%) followed by pseudophakic bullous keratopathy (PBK) (18.9%). Donor age had a negative impact on endothelial cell density (ECD) measured by an eye bank specular microscope (p < 0.001). Median best-corrected visual acuity in logarithm of the minimum angle of resolution units increased from 2.1 to 0.8 at 1 year after PK (p < 0.001). The clear graft rate was 96.7% at year 1, 88.8% at year 2, and 85.5% at year 3. Overall graft survival was 84.9% during a median of 39 months (range: 24–79 months) of follow-up. A higher graft survival rate (67.2%) was observed in KC compared to PBK during 6 years (p < 0.001). Recipients younger than 50 years of age showed a better graft survival rate than those older than 70 years of age (p = 0.037). Donor ECD, time between excision and death, and preservation time had no significant effect on graft survival. Frequent graft rejection episodes (GREs) and additional procedures during surgery had a negative impact on graft survival (p < 0.001 and p = 0.014, respectively). A worse graft survival was observed in group 2 compared to groups 1 and 3 (p = 0.042).

Conclusions: Young recipient age and KC were associated with a better graft survival. Graft endothelial density and preservation time had no impact on graft survival. PBK, low vision at baseline and year 1, frequent GREs, and additional interventions during surgery had a negative impact on graft survivals.     

圆锥角膜基底下神经与角膜形态的相关性研究

目的 研究圆锥角膜（KC）基底下神经与角膜形态的相关性。设计 前瞻性比较性病例系列。研究对象 2018年3月至2019年3月北京同仁医院KC患者（KC组）74例74眼,KC顿挫期组25例25眼,正常对照组24例24眼。方法 通过眼部检查及Pentacam眼前节分析仪诊断KC、KC顿挫期及正常角膜。角膜形态参数采用Pentacam的角膜最大曲率值（Kmax）和角膜最薄厚度值（Minpachy）。应用ACCmetrics软件计算由活体激光共聚焦显微镜（IVCM）获得的基底下神经图片上六种基底下神经参数：角膜神经纤维密度（CNFD）、角膜神经分支密度（CNBD）、角膜神经纤维长度（CNFL）、角膜总分支密度（CTBD）、角膜神经纤维面积（CNFA）、角膜神经纤维宽度（CNFW）。分析KC组角膜基底下神经与角膜形态的相关性,并比较各两组间角膜基底下神经参数的差异。主要指标 Kmax、Minpachy、CNFD、CNBD、CNFL、CTBD、CNFA、CNFW。结果 IVCM定性分析观察到KC组角膜基底下神经迂曲度增加、基底下神经纤维密度明显低,偶可见神经呈束状排列。KC组和正常对照组比较,CNFD、CNBD、CNFL和CNFW差异均有统计学意义（P均<0.05）。KC组和顿挫组比较,CNFL和CNFA差异均有统计学意义（P均<0.05）。顿挫组和正常对照组比较,CNFD和CNFL差异均有统计学意义（P均<0.05）。KC组CNFD、CNFL和CNFW分别与Kmax具有相关性（P=0.001、0.001和0.006）, KC组的CNFD、CNBD、CNFL和CNFW分别与Minpachy具有相关性（P=0.01、0.01、0.004和0.02）。结论 KC患者角膜基底下神经的改变可能早于角膜形态的改变,基底下神经随着疾病的进展而变化。CNFD和CNFL可能是诊断早期圆锥角膜的指标。（眼科, 2020, 29： 118-122）     

圆锥角膜病因学研究进展——遗传、环境刺激、表观遗传的相互作用

圆锥角膜是一种扩张性角膜疾病,以角膜中央变薄、向前凸出呈锥状为特征,可严重影响视力。圆锥角膜病因复杂,迄今为止尚未完全明确,可能是遗传、表观遗传和环境刺激之间相互作用的结果。本文旨在对近年来圆锥角膜病因学的研究进展进行综述,并对未来该领域的研究方向进行展望:阐明表观遗传学的调控路径可能是明确病因的关键;3D培养的体外模型可望为探索圆锥角膜病因和推进治疗提供依据。     

Endoscopic transnasal canaliculorhinostomy for refractory common canalicular obstruction with an unidentifiable lacrimal sac

AIM: To compare the safety and efficacy of conventional versus accelerated (9 mW/cm2) CXL in progressive keratoconus at the 2-year follow-up. METHODS: In this prospective study, consecutive progressive keratoconus patients were randomized to receive either conventional CXL (CCXL) or accelerated CXL (ACXL, using hydroxypropyl methylcellulose-assisted riboflavin imbibition for 10min) at 9 mW/cm2. Visual, refractive, keratometric, topographic, and aberrometric outcomes and stromal demarcation line depth (DLD) measurements were compared at the end of a 2-year follow-up. RESULTS: Thirty-two eyes from 32 patients in the CCXL and 27 eyes from 27 patients in the ACXL groups completed 2-year follow-ups. At 2 years post-CXL, both uncorrected and corrected visual acuities improved significantly in both groups. The improvements in keratometric readings, flattening rate (flattening of the Kmax more than 1D), 3 topographic indices, and vertical coma were significantly better in the CCXL group compared to the ACXL group (P<0.05). The DLD as measured by anterior segment optical coherence tomography or in vivo confocal microscopy was better detectable and significantly deeper in the CCXL group compared to the ACXL group. The deeper DLD was found to be significantly correlated with improvements in the mean keratometry measurements. Progression was noted in 11.1% of eyes in the ACXL group, whereas progression was not observed in any patient eye in the CCXL group. CONCLUSION: In this prospective randomized study, ACXL was less effective in halting the progression of keratoconus at a 2-year follow-up compared to CCXL.