Microstructural assessment of rare corneal dystrophies using real-time in vivo confocal microscopy

Multimodal imaging of pre-Descemet corneal dystrophy

PURPOSE

The aim of this study was to assess structural and histological changes associated with pre-Descemet corneal dystrophy with multimodal in vivo imaging.

METHODS

Retrospective case series including eight corneas from four unrelated male patients with pre-Descemet corneal dystrophy characterized by the presence of punctiform gray opacities located just anterior to the Descemet membrane at slit-lamp examination of both eyes. In vivo confocal microscopy images were obtained in the central, paracentral, and peripheral corneal zones from the superficial epithelial cell layer down to the corneal endothelium in both eyes. Spectral domain optical coherence tomography scans (central and limbal zones) and mapping of both corneas were acquired.

RESULTS

Diffuse small extracellular stromal deposits, presence of enlarged hyperreflective keratocytes in the posterior stroma with either hyperreflective or hyporeflective intracellular dots, and presence of activated keratocytes in the very anterior stroma were observed in all corneas with in vivo confocal microscopy. Spectral domain optical coherence tomography scans showed a hyperreflective line anterior to Descemet's membrane running from limbus to limbus and associated with a second thinner hyperreflective line just beneath Bowman's layer. Fine hyperreflective particles were observed in the posterior, mid, and anterior stroma on optical coherence tomography scans.

CONCLUSION

The clinical presentation and structural anomalies found in isolated sporadic pre-Descemet corneal dystrophy are in favor of a degenerative process affecting corneal keratocytes with no epithelial or endothelial involvement. The maximum damage is found just anterior to the Descemet membrane resulting in pre-Descemet membrane location of stromal opacities. Multimodal imaging of cornea reveals that the disorder affects the whole stroma and it permits better understanding of pre-Descemet corneal dystrophy pathophysiology together with ascertained diagnosis.

Confocal biomicroscopy in four patients with polychromatic corneal dystrophy

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.

CLINICAL CASES

Four women, between 36 and 72 year-old, with the diagnosis of polychromatic corneal dystrophy in routine reviews. None reported visual symptoms or ocular history of interest. Anterior biomicroscopy showed multiple and small multicoloured brilliant opacities in the posterior area of the corneal stroma, with normal epithelium and anterior stroma. The opacities were bilateral and distributed throughout the entire cornea. Direct family members were examined, but none of them showed opacities. In the specular biomicroscopy, a normal endothelium, with pre-descemet hypereflective particles, was observed. With confocal microscopy, there were no abnormalities in epithelium, Bowman layer, or sub-basal nervous plexus. In two cases, the anterior stroma showed hyper-reflective keratocytes and with small hypereflective particles among them. In the middle stroma, hyper-reflective keratocytes were seen in the four cases, two of them showed tiny hypereflective particles, and in the other two there were abnormal keratocytes with prominent cytoplasmic processes. Posterior stroma in the four cases showed a lot of hypereflective keratocytes and hypereflective particles of different sizes. These particles prevented examining the endothelium.

CONCLUSIONS

Polychromatic corneal dystrophy has typical signs that allow it to be diagnosed and characterised. Although the biomicroscopy image only seems to show alterations in the posterior stroma, confocal microscopy shows that the dystrophy affects the entire corneal stroma.

Heredity and in vivo confocal microscopy of punctiform and polychromatic pre-Descemet dystrophy

PURPOSE

To describe and analyze the biomicroscopic features and in vivo confocal microscopy of the crystalline form of pre-Descemet corneal dystrophy (PDCD).

METHODS

We examined two non-related families using biomicroscopy, in vivo confocal microscopy, and a genetic study using a gene panel test, looking for mutations in the PIKFYVE gene.

RESULTS

A slit-lamp examination of the first family revealed polychromatic crystalline punctiform opacities distributed all over the stroma in 8 of 11 family members in three generations with an autosomal dominant inheritance. The second family showed in three of four members in two generations the same opacities located in the pre-Descemet region. It was also a hint for autosomal dominant inheritance. The in vivo confocal microscopy identified numerous rounded and hyperreflective stromal particles measuring 10-15 μm in diameter, with the highest density in the posterior stroma and with normal keratocytes. No systemic disease was diagnosed. No variants or mutations were identified in PIKFYVE gene.

CONCLUSIONS

Polychromatic deposits in patients with Punctiform and Polychromatic Pre-Descemet corneal dystrophy can be located not only in the deep stroma but also in the anterior and middle stroma. Our presentation reveals the possibility of considering this characteristic corneal disorder as a corneal dystrophy of its own and not as a subtype of pre-Descemet corneal dystrophy.

In vivo confocal microscopy of pre-Descemet corneal dystrophy associated with X-linked ichthyosis: a case report

Background

Pre-Descemet corneal dystrophy (PDCD) is characterized by the presence of numerous, tiny, polymorphic opacities immediately anterior to Descemet membrane, which is a rare form of corneal stromal dystrophy and hard to be diagnosed. In vivo confocal microscopy (IVCM) is a useful tool to examine the minimal lesions of the cornea at the cellular level. In this article, we report a rare case of PDCD associated with X-linked ichthyosis and evaluate IVCM findings.

Case presentation

We present a 34-year-old male Chinese patient with PDCD associated with X-linked ichthyosis. Slit-lamp biomicroscopy showed the presence of tiny and pleomorphic opacities in the posterior stroma immediately anterior to Descemet membrane bilaterally. IVCM revealed regular distributed hyperreflective particles inside the enlarged and activated keratocytes in the posterior stroma. Hyperreflective particles were also observed dispersedly outside the keratocytes in the anterior stroma. Dermatological examination revealed that the skin over the patient’s entire body was dry and coarse, with thickening and scaling of the skin in the extensor side of the extremities. PCR results demonstrated that all ten exons and part flanking sequences of STS gene failed to produce any amplicons in the patient.

Conclusions

IVCM is useful for analyzing the living corneal structural changes in rare corneal dystrophies. We first reported the IVCM characteristics of PDCD associated with X-linked ichthyosis, which was caused by a deletion of the steroid sulfatase (STS) gene, confirmed by gene analysis.

Punctiform and Polychromatophilic Dominant Pre-Descemet Corneal Dystrophy

PURPOSE

To describe the slit-lamp appearance and corneal confocal microscopy of autosomal dominant punctiform and polychromatophilic pre-Descemet corneal dystrophy in 3 members of the same family.

METHODS

Slit-lamp examination of a 9-year-old boy showed bilateral polychromatophilic corneal opacities in a pre-Descemet membrane location evenly deposited limbus to limbus, both horizontally and vertically, with an intervening clear cornea. The corneal endothelium was normal on corneal confocal microscopy, with hyperreflective opacities of various sizes located pre-Descemet membrane. Slit-lamp examination of the patient's father and brother revealed identical crystalline deposition in the pre-Descemet corneal stroma. The remainders of the eye examinations were otherwise normal in all 3 individuals, and all were asymptomatic.

RESULTS

The general physical examination and laboratory investigations of the patient were all normal, as were the laboratory investigations of the other 2 family members. There was no progression in the corneal findings over 6 months of follow-up.

CONCLUSIONS

These patients likely illustrate a rare autosomal dominant pre-Descemet crystalline keratopathy that has been reported only once previously.

Screening for MIR184 Mutations in Iranian Patients with Keratoconus

Purpose:

To investigate whether microRNA (MIR)-184 mutations make a substantial contribution to keratoconus (KCN) among affected Iranian patients.

Methods:

A total of 47 Iranian KCN patients, diagnosed based on family history, clinical examinations using slit lamp biomicroscopy, refraction and corneal topography were enrolled in this study. The pri-miR-184 encoding gene obtained from the DNAs of all participants was amplified using polymerase chain reaction and subsequently sequenced by the Sanger dideoxynucleotide protocol. The sequences were compared to MIR184 reference sequence in order to identify sequence variations. The potential effects of a single variation observed on RNA structure was predicted.

Results:

Only one sequence variation, +39G >T, was observed within the pri-miR-184 encoding sequence in one proband. The patient's KCN-affected sister harbored the same variation. The variation was not novel and was recently shown to be present at similar frequencies among large cohorts of KCN patients and control individuals.

Conclusion:

Mutations in MIR-184 are not a major cause of keratoconus among Iranian patients. The pri-miR-184 sequence needs to be screened in larger cohorts in order to establish whether mutations in the gene are present at low frequencies among Iranian patients.

A COL17A1 Splice-Altering Mutation Is Prevalent in Inherited Recurrent Corneal Erosions

PURPOSE

Corneal dystrophies are a genetically heterogeneous group of disorders. We previously described a family with an autosomal dominant epithelial recurrent erosion dystrophy (ERED). We aimed to identify the underlying genetic cause of ERED in this family and 3 additional ERED families. We sought to characterize the potential function of the candidate genes using the human and zebrafish cornea.

DESIGN

Case series study of 4 white families with a similar ERED. An experimental study was performed on human and zebrafish tissue to examine the putative biological function of candidate genes.

PARTICIPANTS

Four ERED families, including 28 affected and 17 unaffected individuals.

METHODS

HumanLinkage-12 arrays (Illumina, San Diego, CA) were used to genotype 17 family members. Next-generation exome sequencing was performed on an uncle-niece pair. Segregation of potential causative mutations was confirmed using Sanger sequencing. Protein expression was determined using immunohistochemistry in human and zebrafish cornea. Gene expression in zebrafish was assessed using whole-mount in situ hybridization. Morpholino-induced transient gene knockdown was performed in zebrafish embryos.

MAIN OUTCOME MEASURES

Linkage microarray, exome analysis, DNA sequence analysis, immunohistochemistry, in situ hybridization, and morpholino-induced genetic knockdown results.

RESULTS

Linkage microarray analysis identified a candidate region on chromosome chr10:12,576,562-112,763,135, and exploration of exome sequencing data identified 8 putative pathogenic variants in this linkage region. Two variants segregated in 06NZ-TRB1 with ERED: COL17A1 c.3156C→T and DNAJC9 c.334G→A. The COL17A1 c.3156C→T variant segregated in all 4 ERED families. We showed biologically relevant expression of these proteins in human cornea. Both proteins are expressed in the cornea of zebrafish embryos and adults. Zebrafish lacking Col17a1a and Dnajc9 during development show no gross corneal phenotype.

CONCLUSIONS

The COL17A1 c.3156C→T variant is the likely causative mutation in our recurrent corneal erosion families, and its presence in 4 independent families suggests that it is prevalent in ERED. This same COL17A1 c.3156C→T variant recently was identified in a separate pedigree with ERED. Our study expands the phenotypic spectrum of COL17A1 disease from autosomal recessive epidermolysis bullosa to autosomal dominant ERED and identifies COL17A1 as a key protein in maintaining integrity of the corneal epithelium.

Characteristics of Pre-Descemet Membrane Corneal Dystrophy by Three Different Imaging Modalities-In Vivo Confocal Microscopy, Anterior Segment Optical Coherence Tomography, and Scheimpflug Corneal Densitometry Analysis

PURPOSE

To evaluate the characteristics of pre-Descemet membrane corneal dystrophy by 3 different imaging modalities: in vivo confocal microscopy (IVCM), anterior segment optical coherence tomography (ASOCT), and Scheimpflug corneal densitometry analysis.

METHODS

A 32-year-old male patient with pre-Descemet membrane corneal dystrophy was subjected to imaging by IVCM, ASOCT, and Scheimpflug tomography.

RESULTS

Slit-lamp biomicroscopy showed the presence of tiny pleomorphic opacities in the posterior stroma, immediately anterior to Descemet membrane bilaterally. On IVCM, pleomorphic, hyperreflective punctate particles were seen both intracellularly and extracellularly in the anterior and mid stroma with increased reflectivity of some keratocytes that, however, were of normal size. These changes increased in severity from the anterior to mid stroma. The posterior stroma had grossly enlarged hyperreflective keratocytes with prominent processes. The hyperreflective particles were also seen scattered on the endothelium. ASOCT revealed a well-delineated homogenous band of increased reflectivity of approximately 70 μm width in the posterior stroma of both eyes with a normal-appearing anterior and mid stroma. Corneal densitometry measured by Scheimpflug optical analysis revealed a higher amount of backscattered light from the posterior stroma with a posterior to anterior ratio of 0.8.

CONCLUSIONS

In pre-Descemet membrane corneal dystrophy, although the structural changes seem to be limited to the posterior stroma as seen clinically and on ASOCT, IVCM demonstrates that the pathology is more extensive involving the entire corneal stroma and endothelium.

Corneal confocal microscopy findings in sporadic cases of pre-descemet corneal dystrophy

PURPOSE

To present corneal confocal microscopy (CCM) findings in a series of patients with pre-Descemet corneal dystrophy (PDCD).

METHODS

A 28-year-old man, a 50-year-old man, a 30-year-old woman, and a 31-year-old man were clinically diagnosed with PDCD on slit lamp microscopic evaluation. All patients were evaluated by means of CCM. The parents of the patients were clinically evaluated. Two of the patients underwent photorefractive keratectomy.

RESULTS

In all the patients, CCM revealed highly reflective stromal particles and pleomorphic structures that included particles in the deep stroma, immediately anterior to the Descemet membrane extending up to 60 μm from endothelium. No evidence of PDCD was observed clinically in the parents of the patients. Postoperative course of photorefractive keratectomy was uneventful for both of the patients.

CONCLUSIONS

With the use of CCM, a specific pattern of findings seemed to be related with PDCD in this series of sporadic cases.

A Case of Bilateral Descemet's Membrane and Subepithelial Opacity: In vivo Laser Confocal Microscopic Study

Purpose

To report the in vivo laser confocal microscopy findings from a patient with Descemet's membrane and subepithelial opacity OU.

Case Report

A healthy 41-year-old male with Descemet's membrane and subepithelial opacity OU was studied. Routine ophthalmic examination, standard slit-lamp biomicroscopy, and in vivo laser confocal microscopic analysis of the entire corneal layer were performed. Slit-lamp biomicroscopy revealed subepithelial opacity in the mid-peripheral to peripheral cornea and numerous opacities located at the level of Descemet's membrane. It was difficult to distinguish the precise histological location of the opacity. In vivo laser confocal microscopy showed numerous hyperreflective particles in the subepithelium to superficial stroma and hyperreflectivity of Descemet's membrane. No abnormalities could be detected in the epithelial cell layer, midstromal layer, deep stromal layer, or endothelial cell layer.

Conclusion

Although the origin of the corneal opacities was unclear, in vivo laser confocal microscopy was useful for observing microstructural abnormalities in a case of Descemet's membrane and subepithelial opacity.

Confocal microscopy of corneal dystrophies

In vivo confocal microscopy (IVCM) of the cornea is becoming an indispensable tool in the cellular study of corneal physiology and disease. This technique offers non-invasive imaging of the living cornea with images comparable to that of ex vivo histology. The ability to provide high-resolution images of all layers in the living cornea has resulted in new discoveries of corneal pathology at the cellular level. The IVCM analysis of corneal dystrophies is of importance to clinicians, as current methods of diagnosis involve slit-lamp characteristics, genetic analysis, and invasive biopsy. IVCM is helpful in evaluating the morphological characteristics of corneal dystrophies at the histological level and may be helpful in diagnosis, determination of progression, and understanding the pathophysiology of disease. The purpose of this review is to describe the principles, applications, and clinical correlation of IVCM in the study of corneal dystrophies.

In vivo confocal microscopy of an apparent deep stroma corneal dystrophy: a case report

A 41-year-old white woman was referred to our Department to rule out the presence of a Fuch's corneal dystrophy. On slit-lamp biomicroscopy, small bilateral punctuate opacities appearing mostly in the posterior stroma were observed, suggesting a differential diagnosis of pre-Descemet's dystrophy as opposed to Cornea Farinata.

Confocal microscopy in the central cornea of both eyes revealed the normal appearance of superficial and basal epithelial layers. However throughout the full thickness of the cornea fine highly refractive granules, localized both in the keratocytes cytoplasm and in the stroma matrix were noted. In both eyes abnormal polymegatism and pleomorphism was observed.

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.

Clinical corneal confocal microscopy

Confocal microscopy allows non-invasive in vivo imaging of the ocular surface. Its unique physical properties enable microscopic examination of all layers of the cornea and have been used to investigate numerous corneal diseases: epithelial changes, numerous stromal degenerative or dystrophic diseases, endothelial pathologies, corneal deposits, infections, and traumatic lesions. It offers a new approach to study the physiological reactions of the cornea to different stimuli and the pathophysiologic events leading to corneal dysfunction in certain diseases. Confocal microscopy proves to be a powerful diagnostic tool and is especially of value in certain corneal diseases by allowing straightforward and non-invasive recognition of the pathologic conditions.

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.

Inherited corneal opacifications with an unusual distribution

PURPOSE

To describe corneal opacities of a new type and distribution in a small family.

METHODS

Family members were interviewed and examined to establish a pedigree and to detect any corneal abnormalities.

RESULTS

Two family members presented with corneal opacities. Both had, in the very peripheral cornea, flat, greyish, rounded opacities, 20-200 microm in diameter, on the Descemet's membrane. In addition, the mother had the same type of opacities over the central cornea just inside the Bowman's layer. The remaining parts of the corneas were clear. Vision was unaffected and the opacities caused no discomfort. There was no other corneal pathology. The subjects' general health was good.

CONCLUSIONS

To our knowledge, these types and distribution of corneal opacities have not been described previously. Although the mode of inheritance at this point is uncertain, we believe the changes are of a dystrophic nature.

Inherited corneal disease: the evolving molecular, genetic and imaging revolution

Advances in molecular genetics and in vivo ocular imaging modalities have enhanced our understanding of the corneal dystrophies. To date at least 11 genes have been identified, in which mutations manifest in corneal disease. In addition there are at least eight other loci identified to which corneal dystrophies have been linked. The information gained from the knowledge of gene function, aberrant protein production, or altered enzyme activity in the cornea, has resulted in greater knowledge of the pathophysiological mechanisms in these disorders. In vivo confocal microscopy has recently enabled microstructural study of dystrophic corneas throughout the disease course, rather than being limited to histopathological analysis of tissue removed at corneal transplantation. This perspective article summarizes the current knowledge, with emphasis on the genes, mutant proteins and resultant mechanisms that lead to manifestations of disease, along with characteristic findings with in vivo confocal microscopy.

In vivo confocal microscopic characteristics of iridocorneal endothelial syndrome

PURPOSE

To analyse five cases of iridocorneal endothelial (ICE) syndrome and describe the microstructural characteristics observed by in vivo confocal microscopy.

METHODS

All five subjects presented with clinical characteristics suggestive of ICE syndrome and were examined clinically by Orbscan II pachymetry and by in vivo confocal microscopy. At least 600 sequential digital confocal images throughout the z-axis were analysed qualitatively and quantitatively for each cornea.

RESULTS

Clinically, all subjects presented with: minimal to moderate corneal oedema, focal to diffuse 'beaten metal' appearance of the corneal endothelium, and varying degrees of iris atrophy. Three subjects had a history of elevated intraocular pressure. In vivo confocal microscopy highlighted two main patterns of endothelial change: small cells (mean maximal diameter of 13.6 +/- 1.5 micro m), with indistinct borders and very bright and prominent, uniform nuclei (two subjects) and larger, epithelioid-like cells (mean maximal diameter of 26.6 +/- 5.5 micro m), with irregular borders and non-homogenous, diversely shaped nuclei (three subjects). Different degrees of alteration of stromal structure, very prominent corneal nerves and unusual syncytia of keratocytes were also observed. Significant oedema of the basal epithelium with increased reflectivity of the intercellular spaces was prominent in all cases.

CONCLUSIONS

Although ICE syndrome is considered to be primarily an endothelial disease, in vivo confocal microscopy demonstrated structural alterations throughout the entire cornea even in clinically mild cases. The ability of in vivo confocal microscopy to localize and accurately measure various elements in different corneal layers will assist differentiation of various presentations of ICE syndrome as this technique becomes increasingly available in clinical practice.

In vivo confocal microscopy in the patients with cornea farinata

PURPOSE

To report in vivo corneal confocal microscopic findings of patients with cornea farinata.

PATIENTS AND METHODS

Two unrelated patients, a 47-year-old man and a 77-year-old woman, with cornea farinata were studied. Examination with a confocal microscope was performed in addition to routine slit-lamp biomicroscopy.

RESULTS

In both cases, slit-lamp biomicroscopy showed numerous small, faint opacities in the deep stroma in both eyes. Using confocal microscopy, highly reflective small particles were observed in the cytoplasm of keratocytes in the deep stroma adjacent to the corneal endothelial layer. No abnormalities could be detected in the epithelial layer, in the mid-stromal layer, at the level of Descemet's membrane, and in the endothelial layer.

CONCLUSIONS

In vivo corneal confocal microscopy is useful for observing stromal abnormalities in cornea farinata. Further investigation of posterior stromal opacities using confocal microscopy may be useful to understand and differentiate various corneal conditions involving primarily deep stromal layers.

In vivo confocal microstructural analysis and surgical management of Brown-Mclean syndrome associated with spontaneous crystalline lens luxation

We report 3 members of an extended family who presented with bilateral peripheral corneal edema consistent with Brown-McLean syndrome. On clinical examination, all eyes demonstrated normal central corneas and marked peripheral edema. In vivo confocal microscopy of the peripheral cornea highlighted similar observations in the 6 eyes including endothelial pigmentation, masked stromal structure due to edema, prominent nerves, and localized basal epithelial edema. In the central cornea, in vivo confocal microscopic observations highlighted large cellular structures with prominent nuclei in groups consisting of several cells of similar appearance. In vivo confocal microscopy may enhance the diagnosis of Brown-McLean syndrome and may be used for dynamic evaluation and postoperative follow-up of the structural corneal changes.

In vivo confocal microscopy of the human cornea

AIMS

To describe the optics of in vivo confocal microscopy, its advantages over previous methods, and to summarise the literature that arose from its use for the observation of the human cornea. A critical review of the clinical usefulness of this new technology for the corneal examination is undertaken.

METHODS

Confocal microscopes obtain increased resolution by limiting the illumination and observation systems to a single point. Rapid scanning is used to reconstruct a full field of view and allows for "real time" viewing.

RESULTS

Coronal sections of the in situ epithelium, Bowman's membrane, stroma, and endothelium can be visualised at a resolution of 1-2 micro m. A backscattered light intensity curve allows objective measurements of sublayer thickness and corneal haze to be taken. In vivo confocal microscopy is therefore particularly useful in the areas of infective keratitis, corneal dystrophies, refractive surgery, and contact lens wear, where it aids in differential diagnosis and detection of subtle short and long term changes. Real time endothelial cell assessment can also be performed.

CONCLUSION

Because of their ability to visualise living tissue at cellular levels, confocal microscopes have proved useful additions to the current clinical tools.

In vivo microstructural analysis of the cornea in Scheie's syndrome

PURPOSE

To analyze clinical and in vivo microstructural characteristics of both corneas of a 13-year-old male subject with Scheie's syndrome and compare the observations with the pathologic reports in the literature.

METHODS

Standard clinical examination and real-time, slit-scanning in vivo confocal microscopy were performed and repeated after 1 year.

RESULTS

In vivo confocal microscopy images at all cellular layers demonstrated brighter intercellular spaces than those of normal corneas. Cicatrization of the anterior stroma was identified, and the keratocytes of the middle and posterior stroma exhibited markedly altered morphology, often round or elliptical in shape, and with clearly demarcated, hyporeflective centers. The nerve fibers of the subbasal plexus were somewhat more irregular and difficult to distinguish, possibly due to underlying fibrosis.

CONCLUSIONS

The potential of in vivo confocal microscopy to highlight microstructural alterations of the intact human cornea and evaluate such changes over time might reduce reliance on histopathologic investigations in such conditions and contribute to the ophthalmic management of the mucopolysaccharidoses in the future.