In vivo confocal microscopy of pre-Descemet's membrane corneal dystrophy

Pre-Descemet's membrane corneal dystrophy is clinically characterized by the presence of numerous tiny pleomorphic opacities located in the deep stroma immediately anterior to Descemet's membrane. A 35-year-old man, clinically diagnosed with pre-Descemet's corneal dystrophy, was examined by in vivo slit scan confocal microscopy. The pleomorphic structures containing dense hyperreflective inclusions in the posterior stroma were revealed in vivo. To the best of the authors' knowledge, it is consistent with the result of the previous histological study, but different from other reports using in vivo confocal microscopy.     

Differential diagnosis of corneal oedema assisted by in vivo confocal microscopy

The purpose of this study was to demonstrate microstructural differences between clinically similar, but aetiologically different, cases of corneal oedema in four subjects. In vivo confocal microscopy highlighted oedema of the basal epithelium, prominent nerve–keratocyte interactions, and typical ‘epithelialization’ of the endothelium in a case of iridocorneal endothelial syndrome; however, a similar microstructural appearance was observed in a case of presumed herpetic disciform keratitis. The latter diagnosis was subsequently revised on this basis. Confocal examination of Fuchs’ endothelial dystrophy demonstrated oedema of the basal epithelium, prominent wing cells, anterior stromal alterations, fibrosis of Descemet’s membrane and a typical ‘strawberry’ appearance of the endothelium. In contrast, in vivo microstructural examination of bilateral keratoconus with hydrops confirmed oedema mainly involving the epithelium and anterior stroma. In vivo confocal microscopy allows the clinician to observe the living cornea at a microstructural level and to better diagnose and differentiate borderline or unusual cases of corneal oedema.     

Imaging posterior polymorphous corneal dystrophy by in vivo confocal microscopy

To identify features of posterior polymorphous dystrophy (PPMD) by in vivo confocal microscopy, the corneas of a female patient with PPMD were examined using slit‐lamp biomicroscopy and slit‐scanning in vivo confocal microscopy. Characteristic endothelial vesicular and band lesions were seen clinically and easily identified using in vivo confocal microscopy. However, endothelial pleomorphism, an increased density and reflectance of posterior stromal keratocytes, and prominence of corneal nerves were also delineated. In vivo confocal microscopy enhances clinicopathological diagnosis and follow up of corneal dystrophies with subtle clinical presentations, such as PPMD.     

颗粒状角膜营养不良活体共焦显微镜形态学研究

目的研究颗粒状角膜营养不良角膜各层组织的共焦显微镜形态改变。方法应用Confoscan2.0共焦显微镜对13例(26眼)颗粒状角膜营养不良患者的角膜进行扫描检查,记录与分析各层角膜图像。结果所有患眼前基质细胞及16/26眼后基质细胞结构不清,排列紊乱,并可见短棒状多形性强反光;6/26眼前弹力层不规则并增厚,神经纤维密度明显下降;6/26眼角膜上皮基底细胞层可见不定型的强反光;2/26眼角膜上皮细胞边界不清,排列呈疏松的蜂窝状,并出现不透明的强反光;所有患者角膜内皮细胞形态基本正常。视力0.3以下的患眼角膜上皮细胞层、上皮基底细胞层、前弹力层、后基质层发生形态异常的比例高于0.3以上的患眼(P<0.05)。结论1.共焦显微镜可活体检查颗粒状角膜营养不良角膜组织各层结构,起到类似病理组织切片的作用。2.前基质层形态异常可能是颗粒状角膜营养不良最基本的共焦显微镜形态特征,病情越重,前基质层以外的其它层次发生形态异常的可能性越大,但内皮细胞层一般不受累。3.共焦显微镜检查对颗粒状角膜营养不良手术方式的选择具有一定的参考价值。     

Biomicroscopia confocal en 4 pacientes con distrofia corneal policromática

Introduction

Polychromatic corneal dystrophy is an unusual pre-descemet dystrophy, about which there are very few publications. The findings are presented in a case series of four patients with polychromatic corneal dystrophy, using a slit lamp, specular biomicroscopy, and confocal microcospy.

In vivo confocal laser-scanning microscopy to characterize wound repair in rabbit corneas after collagen cross-linking

Background: Collagen cross‐linking using the photosensitizer riboflavin combined with ultraviolet A light was developed to stiffen the cornea by increasing its mechanical and biochemical stability. Investigation of post‐treatment events, such as wound healing, is important to evaluate possible risks and to optimize treatment protocols. This in vivo confocal laser‐scanning microscopy study in rabbits was conducted to provide a quantitative and qualitative analysis of corneal wound repair over 16 weeks following collagen cross‐linking. Methods: Six New Zealand White rabbits underwent riboflavin/ultraviolet A cross‐linking. In vivo confocal laser‐scanning microscopy using a Heidelberg Retina Tomograph equipped with a Rostock Cornea Module was performed preoperatively and at 2, 4, 8, 12 and 16 weeks postoperatively. Results: From 2 weeks onwards the epithelium demonstrated no abnormalities. Evidence of inflammation was visualized in the intermediate, basal cells and Bowman's membrane. Nerve fibre regeneration was first noted at 12 weeks. Keratocyte activation and hyperreflective extracellular matrix were observed consistently, but by 16 weeks keratocyte activation was diminished, and extracellular matrix resumed normal reflectivity. Cell density in the posterior stroma and endothelium regained preoperative values by 4 weeks, although anterior stroma keratocyte cell density was still reduced by about 10% at 16 weeks. Conclusions: Complete qualitative and quantitative characterization of corneal wound repair was achieved by in vivo confocal laser‐scanning microscopy over 16 weeks following collagen cross‐linking in rabbits. In terms of assessing the ever‐increasing range of cross‐linking protocols, in vivo confocal laser‐scanning microscopy may contribute to minimizing the number of experimental animals, because multiple examinations of the same cases are possible over time.     

In vivo confocal microscopy of climatic droplet keratopathy

We describe the corneal microstructural changes in a patient with spheroidal degeneration using in vivo confocal microscopy. Multiple hypo‐ and hyper‐reflective spherical lesions were observed in the anterior corneal stroma and Bowman's layer ranging from 45 to 220 μm in size. The corneal epithelium, posterior stroma and endothelium were otherwise unaffected. In vivo confocal microscopy demonstrates good correlation with excised histological samples in climatic droplet keratopathy. It provides a non‐invasive technique to examine the living cornea for degenerative disease and acts as a bridge between clinical and laboratory observations.     

Ultrastructural and in vivo confocal microscopic evaluation of interface after Descemet’s Stripping Endothelial Keratoplasty in rabbits

Purpose: To study healing at the donor–recipient interface after Descemet’s Stripping Endothelial Keratoplasty (DSEK) in rabbits by ultrastructural and in vivo confocal microscopic evaluation. Methods: The right eye of eight New Zealand White rabbits underwent DSEK. Postoperatively, each rabbit was subjected to routine slitlamp examination daily for 2 weeks and then weekly for 6 weeks. In vivo confocal microscopic evaluation was performed at 1, 2, 4 and 8 weeks. Two rabbits were randomly chosen at 1, 2, 4 and 8 weeks for transmission electron microscopic examination. Results: Interface haze decreased with each follow‐up visit. Activated keratocytes and associated cellular processes were evident throughout all the follow‐ups with in vivo confocal microscopy. Highly reflective particles were left at the interface until the end‐point of the study. Upon ultrastructural evaluation, increased rough‐surface endoplasmic reticulum in keratocytes, clefts, folds and retained Descemet’s membrane (DM) were found. Conclusion: Clefts lack of adherence at the interface and degenerated keratocyte may make up the highly reflective particles. In addition, retained DM does not appear to affect adhesion and very minimal healing is produced at the DM–stroma smooth interface, which permits better quality of vision in Descemet’s membrane endothelial keratoplasty.     

In vivo confocal microscopy findings in a patient with posterior amorphous corneal dystrophy

A 21-year-old man, with bilateral posterior amorphous corneal dystrophy, was studied by biomicroscopy, corneal topography and in vivo confocal microscopy. The best-corrected visual acuity was 6/21 in the right eye and 6/6.9 in the left eye. Biomicroscopy revealed bilateral, asymmetric, sheet-like opacification at the deep posterior stromal layer. The corneal topography displayed asymmetric against-the-rule astigmatism in the right eye and prominent steepening at the inferior paracentral cornea in both eyes. In vivo confocal microscopy of the corneas demonstrated microfolds and hyper-reflective layer at the posterior stroma just adjacent to the endothelial layer. The epithelium, Bowman's membrane, anterior stroma and the endothelial layer were normal. In vivo confocal microscopy is useful in evaluating the corneal dystrophies.     

In vivo confocal microscopy of fleck dystrophy

PURPOSE: To use in vivo confocal microscopy to evaluate corneas with fleck dystrophy. METHODS: Both eyes of three patients with corneal fleck dystrophy were examined with a scanning slit confocal microscope. Corneal epithelium, stroma, and endothelium were evaluated, as well as the basal epithelial and stromal nerves. RESULTS: The epithelium did not show any anomalies, but the basal nerves showed hyperreflective inclusions. Throughout the entire stroma, hyperreflective dots of various shapes were seen. These consisted mostly of spherical matter with a diameter of 3-5 microm and were sometimes enclosed in cyst-like structures. The majority of the stromal cells and stromal nerves appeared normal. The endothelial cell layer was unaffected. CONCLUSION: In vivo confocal microscopy demonstrates previously unreported inclusions in the basal nerves of fleck dystrophy corneas. In addition to this new finding, the study confirms earlier histopathologic reports, demonstrating accumulation of pathologic material in the stromal cells.     

A review of the evidence for in vivo corneal endothelial regeneration

Human corneal endothelium has long been thought to be a nonmitotic cell layer with no endogenous reparative potential. Pathologies that damage endothelial function result in corneal decompensation and, if untreated, blindness. The mainstay of treatment involves partial or complete corneal replacement, amounting to 40% of all corneal transplants performed worldwide. We summarize the case reports describing complications postoperatively in the form of (sub)total graft detachment and those resulting in postoperative bare stroma. Complications during cataract and glaucoma surgeries leading to an uncovered posterior cornea are also included. We discuss the newer treatment strategies that are alternatives for current Descemet membrane endothelial keratoplasty and Descemet stripping automated endothelial keratoplasty, including partial grafts and stripping of the diseased cell layer. In more than half of the cases reviewed, corneal transparency returned despite incomplete or no corneal endothelial cell transplantation. We question the existing paradigm concerning corneal endothelial wound healing in vivo. The data support further clinical study to determine the safety of simple descemethorexis in central endothelial pathologies, such as Fuchs endothelial corneal dystrophy, where presence of healthy peripheral cells may allow successful corneal recompensation without the need for donor cells.     

In-vivo confocal microscopy of iridocorneal endothelial syndrome

Background: We carried out a study by in-vivo confocal microscopy to investigate the appearance of iridocorneal endothelial (ICE) syndrome, and discuss its diagnostic potential. Methods: Twelve patients, each with unilateral ICE syndrome, had both their eyes examined by in-vivo confocal microscopy. The images were recorded and analyzed by the use of proprietary software. Endothelium density, average endothelial area, coefficient of variation of cell size, percentage of hexagonal cells, and nerve fiber diameter were measured in both the anterior and posterior stroma. Corneal thickness was also measured for both eyes. A non-parametric test was used to compare differences between the affected eye and the contralateral healthy one. Results: In-vivo confocal microscopy highlighted two main patterns of abnormal “epithelioid-like” endothelium, both characterized by marked hyperreflective nuclei and loss of regularity in cellular size and shape. The first pattern was relatively regular cell size and shape, conserving a pattern similar to that of normal endothelial cells. However, the cells lost normal hexagonality and presented prominent uniform “cobblestone-like” nuclei occupying the central area of the cells. The second type was more irregular in cellular size and shape, with hyperreflective diversely shaped nuclei adjacent to the boundaries of the cells. Cells with two nuclei could be found in both types. Compared with the contralateral eye, the stromal nerve fibers in affected eyes were unusually thicker and distorted. Nerve diameters in the anterior stroma of affected eyes and contralateral eyes were 5.7 ± 0.5 μm and 3.2 ± 0.2 μm, respectively; those in the posterior stroma were 10.8 ± 0.3 μm and 6.6 ± 0.4 μm, respectively (both P < 0.001). Conclusions: Application of confocal microscopy indicates that ICE syndrome is characterized by pleomorphic epithelioid-like endothelial cells with hyperreflective nuclei. The technique has great potential in diagnosing ICE syndrome, especially in cases with corneal edema.     

Changes in corneal structure observed with confocal microscopy during Fuchs endothelial dystrophy

PURPOSE: The study aimed to in vivo evaluate corneal structure in Fuchs' dystrophy. MATERIAL AND METHODS: Forty-two eyes of 21 patients (11 women and 10 men) aged 34-80 (mean 60.8) were studied. Sixteen patients presented clinical symptoms. The cornea was examined using a Confoscan P4 scanning slit confocal microscope (Tomey). Before examination, the cornea was anesthetized with 0.5% propacaine (Alcaine, Alcon) in order to inhibit the corneopalpebral reflex. A 40x microscope objective was covered with a drop of polyarylic acid gel (Vidisic, Mann Pharma) and then it was moved horizontally close to the patient's cornea and the examination was carried out. RESULTS: In the early stage of Fuchs dystrophy, slit biomicroscopy revealed fine dark spots within the corneal endothelium, while in the advanced stage the cornea had the appearance of beaten metal. On confocal microscopy, there were diffused hyporeflective areas in the early-stage disease. The endothelial cells located beyond these areas were pleomorphic and polymegathic. In the late stage we observed diffused hyporeflective areas surrounded by hyperreflective endothelial cells, which could not be analyzed separately. Within the corneal stroma, the collagen fibers were blurred and the background illumination was increased. In the posterior part of the stroma, dark bands were seen. The epithelium contained cystic structures (blisters). The membranes of the basal cells were thickened and the background illumination was increased. CONCLUSIONS: Confocal microscopy allows to diagnose Fuchs dystrophy and visualize endothelial cells within the swollen cornea.     

后部多形性角膜营养不良49例共聚焦显微镜影像学观察

目的:探讨49例后部多形性角膜营养不良(PPCD)患者在共聚焦显微镜(IVCM)下的影像学特征。方法:回顾性病例研究。收集我院2013-01/2021-01诊断为PPCD患者49例86眼,包括男32例,女17例,平均年龄42.5±22.9岁。所有患者均进行IVCM检查,分析角膜内皮细胞密度及不同类型病变的镜下特点。结果:所有患者病灶区内皮细胞数量均较外周细胞数量低。IVCM下病变呈1型囊泡型的有44眼(51%),表现为角膜内皮层的圆形或不规则弹坑样病灶,单个或多个出现;2型条带型16眼(19%),表现为边缘弧形凸起,部分可见似赘疣样影像散在或条索状分布;3型弥漫型26眼(30%),表现为内皮细胞大面积缺失,大部分区域内皮成像不清,呈匍匐样、条索样延展的凸起,成像较清晰处部分同条带型病灶。观察病例中有2例患者随访4～5a, IVCM下病灶均较前有变化,包括中央角膜内皮数量的减少和上皮层铁质沉着等。结论:IVCM能够显示PPCD患者各期内皮细胞和Descemet膜水平的特征性显微结构改变,通过观察其影像学特点可以为疾病提供有效的诊断价值。     

圆锥角膜行去上皮角膜胶原交联术后角膜微结构的变化

目的：采用共焦显微镜观察进展期圆锥角膜行去上皮角膜胶原交联术后角膜微结构的变化。

方法：选取2016-02/2017-02于我院行上皮角膜胶原交联术治疗的进展期圆锥角膜患者11例15眼,分别于手术前后行共焦显微镜检查,观察角膜微结构变化。

结果：术后早期角膜上皮下神经纤维显著减少或消失; 角膜前基质呈蜂窝状,几乎无典型的角膜基质细胞,术后3mo基质细胞开始出现,术后12mo基质细胞数量几乎恢复到术前水平,但角膜上皮下神经仍稀疏,未达到术前水平; 术后后部角膜基质细胞和内皮细胞大小及形态未受影响。

结论：角膜胶原交联术后角膜微结构发生变化最明显的是上皮下神经纤维和前基质细胞,但随着随诊时间的延长,这种变化呈逐渐减弱趋势。     

First Identification of a Triple Corneal Dystrophy Association: Keratoconus,Epithelial Basement Membrane Corneal Dystrophy and Fuchs’ Endothelial Corneal Dystrophy

Purpose

To report the observation of a triple corneal dystrophy association consisting of keratoconus (KC), epithelial basement membrane corneal dystrophy (EBMCD) and Fuchs’ endothelial corneal dystrophy (FECD).

Methods

A 55-year-old male patient was referred to our cornea service for blurred vision and recurrent foreign body sensation. He reported bilateral recurrent corneal erosions with diurnal visual fluctuations. He underwent corneal biomicroscopy, Scheimpflug tomography, in vivo HRT confocal laser scanning microscopy and genetic testing for TGFBI and ZEB1 mutations using direct DNA sequencing.

Results

Biomicroscopic examination revealed the presence of subepithelial central and paracentral corneal opacities. The endothelium showed a bilateral flecked appearance, and the posterior corneal curvature suggested a possible concomitant ectatic disorder. Corneal tomography confirmed the presence of a stage II KC in both eyes. In vivo confocal laser scanning microscopy revealed a concomitant bilateral EBMCD with hyperreflective deposits in basal epithelial cells, subbasal Bowman''s layer microfolds and ridges with truncated subbasal nerves as pseudodendritic elements. Stromal analysis revealed honeycomb edematous areas, and the endothelium showed a strawberry surface configuration typical of FECD. The genetic analysis resulted negative for TGFBI mutations and positive for a heterozygous mutation in exon 7 of the gene ZEB1.

Conclusion

This is the first case reported in the literature in which KC, EBMCD and FECD are present in the same patient and associated with ZEB1 gene mutation. The triple association was previously established by means of morphological analysis of the cornea using corneal Scheimpflug tomography and in vivo HRT II confocal laser scanning microscopy.Key words: Keratoconus, Fuchs’ endothelial corneal dystrophy, Epithelial basement membrane dystrophy, Cogan dystrophy, Confocal microscopy, ZEB1     

Long-term microstructural changes following epikeratophakia: in vivo confocal microscopy study

The unilateral epikeratophakic eye of a 20-year-old woman with a history of congenital cataracts was examined using laser scanning in vivo confocal microscopy 17 years after transplantation. In vivo confocal microscopy demonstrated a reduced keratocyte density in the grafted lenticule and the host stroma, with unusual elongated and tortuous hyperreflective branching structures in the anterior stroma of the host cornea. The sub-basal nerve plexus was present in the lenticule, although with a reduced nerve density. The appearance of the host endothelium was similar to that observed in Fuchs endothelial dystrophy. Dramatic microstructural changes were observed in almost all layers of the cornea 17 years after epikeratophakia. Although no longer performed as routine practice, in vivo confocal microscopy examination of epikeratophakia has provided fascinating insight into the potential corneal adaptations at a cellular level.     

In vivo confocal microscopy of subepithelial infiltrates in human corneal transplant rejection

PURPOSE: Corneal allograft rejection is the leading cause of penetrating keratoplasty failure in the first year after surgery. We report 2 cases of subepithelial infiltrates in corneal transplant rejection imaged by in vivo confocal microscopy. METHODS: Case report and review of relevant literature. RESULTS: Two subjects with subepithelial infiltrates in previously clear penetrating corneal transplants were assessed. In vivo confocal microscopy revealed focal accumulations of hyperreflective dendritic-like particles, postulated to represent Langerhans cells, at the level of the basal epithelium and Bowman membrane. Altered keratocytes with visible cytoplasmic processes were observed posterior to these foci. CONCLUSIONS: To our knowledge, these are the first reported cases of in vivo confocal microscopy appearance of corneal allograft rejection in humans. In vivo confocal microscopy may provide a valuable clinical tool to aid in the diagnosis of early corneal transplant rejection and in the differential diagnosis of other inflammatory conditions of the cornea.     

Dystrophia Helsinglandica – corneal morphology,topography and sensitivity in a hereditary corneal disease with recurrent erosive episodes

Purpose: The aim of this study was to describe the morphology, corneal topography and sensitivity in individuals with Dystrophia Helsinglandica. This autosomal dominant corneal disease is characterized by recurrent corneal erosive episodes and progressive subepithelial fibrosis not significantly affecting visual acuity. Methods: The corneas of nine affected and nine unaffected individuals were examined using slit‐lamp biomicroscopy, in vivo confocal microscopy (IVCM) and videokeratography. Corneal mechanical sensitivity was also measured using a non‐contact esthesiometer. Results: Slit‐lamp biomicroscopy revealed that the affected individuals represented different stages of corneal changes, from a nearly normal cornea to subepithelial fibrosis of the central cornea. Corneal changes in affected individuals did not significantly decrease the best spectacle‐corrected visual acuity. In vivo confocal microscopy detected morphological changes in the epithelium and stroma. Subepithelial opacity formation including altered keratocytes could be found in the anterior stroma in all affected eyes. With the exception of two eyes (one affected and one unaffected), all videokeratographies showed irregular astigmatism. Corneal sensitivity was significantly lower in affected individuals (p = 0.01). Age and corneal sensitivity showed no correlation. Conclusion: The main morphological findings in affected individuals were discrete and progressive subepithelial fibrosis, in the in vivo confocal microscope corresponding to optically dense extracellular matrix and activated keratocytes. Subbasal nerve morphology was changed in the affected family members who also showed a decreased corneal sensitivity. The findings are per se not specific to the disease. The changes probably reflect a healing response to erosive events on the corneal surface influenced by the genotype.     

Treatment of Inferior Descemet Membrane Detachment Secondary to Cataract Surgery with Air Injection and Supine Head Position

Purpose: To describe a case of a patient with inferior Descemet membrane detachment that resolved after injection of small air bubble and supine positioning.

Methods: A patient presented two weeks after cataract surgery with inferior persistent corneal edema. A Descemet membrane detachment involving the inferior cornea was revealed. Injection of small air bubble was performed and the patient was advised to stay in a supine position for the next two hours and then as much as reasonably possible to allow the air bubble to press the Descemet to the posterior corneal stroma.

Results: Five days after injection, the Descemet membrane was reattached to the corneal stroma and the cornea became clear without any evidence of edema. One month post-air injection the cornea remained clear and the Descement membrane attached.

Conclusions: Air injection with supine position was efficient for the resolution of inferior partial Descemet detachment after cataract surgery. The edema resolved without any further intervention.