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

Case report: A case of corneal deposits between binocular descemet membrane and corneal endothelial layer after small-incision lenticule extraction (SMILE) followed by HPV vaccine

Background

Deposits located between the Descemet memberane and the corneal endothelial layer in both eyes has not yet been reported after SMILE.

Case report

Grayish white fine deposits was found between the Descemet memberane and the corneal endothelial layer in both eyes of the patient's cornea, and no other abnormalities were observed in the anterior and posterior segments of patient's eyes with ophthalmic examination instrument. However, the visual acuity of patient remained unchanged. Significantly, the patient had a sister who had undergone the same procedure a year earlier without any complications. After careful questioning, we learned that the patient received the 9-valent human papillomavirus (HPV) vaccine on the third post-operative day without any other special experiences. We performed immunological examination and genetic testing on the patient. The results of immunological examination of patient showed no obvious abnormality, which was consistent with the routine trend after vaccination. In particular, a homozygous variation of the ARSG gene was found in the patient and her sister.

Conclusion

There are two possible causes of corneal changes in patients. The first is IGA elevation caused by vaccination, deposited in the cornea. Second, the ARSG gene mutation of the patient leads to a potential congenital corneal dystrophy, and clinical manifestations occur under the stimulation of the vaccine.

Corneal dystrophies

Corneal dystrophies are broadly defined as inherited disorders that affect any layer of the cornea and are usually progressive, bilateral conditions that do not have systemic effects. The 2015 International Classification of Corneal Dystrophies classifies corneal dystrophies into four classes: epithelial and subepithelial dystrophies, epithelial-stromal TGFBI dystrophies, stromal dystrophies and endothelial dystrophies. Whereas some corneal dystrophies may result in few or mild symptoms and morbidity throughout a patient's lifetime, others may progress and eventually result in substantial visual and ocular disturbances that require medical or surgical intervention. Corneal transplantation, either with full-thickness or partial-thickness donor tissue, may be indicated for patients with advanced corneal dystrophies. Although corneal transplantation techniques have improved considerably over the past two decades, these surgeries are still associated with postoperative risks of disease recurrence, graft failure and other complications that may result in blindness. In addition, a global shortage of cadaveric corneal graft tissue critically limits accessibility to corneal transplantation in some parts of the world. Ongoing advances in gene therapy, regenerative therapy and cell augmentation therapy may eventually result in the development of alternative, novel treatments for corneal dystrophies, which may substantially improve the quality of life of patients with these disorders.

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.

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.