Herpes simplex virus linear endotheliitis in a post-keratoplasty patient: A case report

Viral Keratitis, Surgical Intervention in Viral Keratitis, Challenges in Diagnosis and Treatment of Viral Keratitis, HSV, HZV

Viral keratitis is a significant cause of ocular morbidity and visual impairment worldwide. In recent years, there has been a growing understanding of the pathogenesis, clinical manifestations, and diagnostic modalities for viral keratitis. The most common viral pathogens associated with this condition are adenovirus, herpes simplex (HSV), and varicella-zoster virus (VZV). However, emerging viruses such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), and Vaccinia virus can also cause keratitis. Non-surgical interventions are the mainstay of treatment for viral keratitis. Antiviral agents such as Acyclovir, Ganciclovir, and trifluridine have effectively reduced viral replication and improved clinical outcomes. Additionally, adjunctive measures such as lubrication, corticosteroids, and immunomodulatory agents have alleviated symptoms by reducing inflammation and facilitating tissue repair. Despite these conservative approaches, some cases of viral keratitis may progress to severe forms, leading to corneal scarring, thinning, or perforation. In such instances, surgical intervention becomes necessary to restore corneal integrity and visual function. This review article aims to provide an overview of the current perspectives and surgical interventions in managing viral keratitis. The choice of surgical technique depends on the extent and severity of corneal involvement. As highlighted in this article, on-going research and advancements in surgical interventions hold promise for further improving outcomes in patients with viral keratitis.

Herpes simplex keratitis: A brief clinical overview

The aim of our minireview is to provide a brief overview of the diagnosis, clinical aspects, treatment options, management, and current literature available regarding herpes simplex keratitis (HSK). This type of corneal viral infection is caused by the herpes simplex virus (HSV), which can affect several tissues, including the cornea. One significant aspect of HSK is its potential to cause recurrent episodes of inflammation and damage to the cornea. After the initial infection, the HSV can establish a latent infection in the trigeminal ganglion, a nerve cluster near the eye. The virus may remain dormant for extended periods. Periodic reactivation of the virus can occur, leading to recurrent episodes of HSK. Factors triggering reactivation include stress, illness, immunosuppression, or trauma. Recurrent episodes can manifest in different clinical patterns, ranging from mild epithelial involvement to more severe stromal or endothelial disease. The severity and frequency of recurrences vary among individuals. Severe cases of HSK, especially those involving the stroma and leading to scarring, can result in vision impairment or even blindness in extreme cases. The cornea's clarity is crucial for good vision, and scarring can compromise this, potentially leading to visual impairment. The management of HSK involves not only treating acute episodes but also implementing long-term strategies to prevent recurrences and attempt repairs of corneal nerve endings via neurotization. Antiviral medications, such as oral Acyclovir or topical Ganciclovir, may be prescribed for prophylaxis. The immune response to the virus can contribute to corneal damage. Inflammation, caused by the body's attempt to control the infection, may inadvertently harm the corneal tissues. Clinicians should be informed about triggers and advised on measures to minimize the risk of reactivation. In summary, the recurrent nature of HSK underscores the importance of both acute and long-term management strategies to preserve corneal health and maintain optimal visual function.

PCR testing for herpesviruses in aqueous humor samples from patients with and without clinical corneal endothelial graft rejection

To compare prevalence of positive PCR tests for herpesviruses between patients with and without a history of clinical corneal endothelial allograft rejection (AGR). Retrospective cross-sectional study with two-group comparison. A total of 307 aqueous humor (AH) samples from 235 Patients and 244 eyes who underwent penetrating keratoplasty or Descemet membrane endothelial keratoplasty or had a diagnostic AH aspiration due to clinical AGR between 2019 and 2023 were tested for DNA of herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV). PCR test results were compared between the two groups (with/without AGR). Another sub-analysis examined the results of patients without a history of herpetic keratitis. A total of 8% of eyes with clinical AGR (9/108) had a positive PCR result for one of the herpesviruses (HSV:3, CMV:3, EBV:2, VZV:1). All patients in the group without AGR had negative PCR results for all previous viruses (0/136). The difference was statistically significant (p < 0.001). The sub-analysis of eyes without a history of herpetic keratitis also revealed significantly more positive herpes PCR results (7/87) in eyes with AGR than in eyes without AGR (0/42, p = 0.005). Clinical AGR after keratoplasty shows a significant correlation to viral replication. Herpetic infection and AGR could occur simultaneously and act synergistically. Timely differentiation between active herpetic infection and/or AGR is pivotal for proper treatment and graft preservation.

Presumed herpes simplex virus endotheliitis following ultra-thin Descemet's stripping automated endothelial keratoplasty

A 78-year-old male underwent ultra.thin DSAEK for PBK (OS) and achieved BCVA 6/12 at 9 months. The patient developed allograft rejection 10 months postoperatively and was treated with IV methyl prednisolone, systemic, and topical steroids. The patient then improved and achieved 6/18 BCVA at 8 weeks. Topical prednisolone 1% twice daily was continued. Six weeks later, the patient developed fever and diminished vision and had high IOP, corneal edema, and keratic precipitates on endothelium. Considering it to as second episode of graft rejection, IV methyl prednisolone and topical steroids were given. Seeing no response, presumed HSV endotheliitis was considered as diagnosis and treated with steroids, oral acyclovir. The patient improved and achieved BCVA 6/24 with no subsequent recurrence during 11 months follow-up.

Clinical consequences of herpes simplex virus DNA in donor corneas: Different prognosis and management of endothelial keratoplasty and deep anterior lamellar keratoplasty

BACKGROUND

There is still controversy over the necessity of screening donor corneas for herpes simplex virus (HSV). Currently, no study reported the outcomes of different types of keratoplasty with HSV-positive donor corneas.

OBJECTIVES

To describe the clinical consequences of four patients who underwent keratoplasty by sharing double corneas from a single donor, both of which were positive for HSV-1 DNA by polymerase chain reaction.

STUDY DESIGN

A retrospective case series study.

RESULTS

Both patients who underwent endothelial keratoplasty (EK) developed persistent corneal edema with or without keratic precipitates, and mild anterior chamber inflammation on postoperative day 3 and 17 respectively. Despite adequate antiviral treatment, they developed graft detachment subsequently and experienced graft replacement. Transmission electron microscopy showed denuded Descemet's membrane without any endothelial cells on both removed grafts and viral particles were identified within the residual posterior stroma of the thicker graft. As for those who underwent deep anterior lamellar keratoplasty, one patient presented with graft rejection for the sake of self-discontinuation of all anti-rejection agents. The other's graft remained clear at the final follow-up.

CONCLUSIONS

HSV existed in the posterior stromal and endothelial layer of the donor corneas. Reactivation of HSV and severe endothelial loss may occur on corneal endothelial grafts in the early postoperative period while anterior lamellar grafts could be quiescent. Considering the possibility of graft failure caused by viral reactivation, it's of great significance to screen for viral DNA in donor corneas prior to the surgery, especially for EK.

Ocular manifestations of herpes simplex virus

PURPOSE OF REVIEW

To review ocular manifestations and complications of herpes simplex virus (HSV) and discuss recent advancements in diagnostic and treatment strategy.

RECENT FINDINGS

In-vivo confocal microscopy has expanded our understanding of corneal nerve degeneration, corneal dendritic cell activity, and changes in biomechanical properties in HSV keratitis. Although currently available only as a research tool, metagenomic deep sequencing has the potential to improve diagnostic accuracy beyond the well established PCR technology, especially in atypical cases. Development of an HSV vaccine has shown some encouraging results in a murine model. New treatment options for neurotrophic cornea offer promise, specifically cenegermin nerve growth factor.

SUMMARY

Ocular herpes simplex infection and its complications continue to cause significant visual burden and decreased quality of life. Familiarity with its clinical features, wider adoption of viral PCR diagnostic technology, and recognition of the need for long-term maintenance medications for recurrent or chronic cases form the basis for effective management. Metagenomic deep sequencing, the development of a herpes vaccine, and cenegermin nerve growth factor offer promise as diagnostic, preventive, and therapeutic options, respectively.