Activation of Cytomegalovirus corneal endotheliitis following laser in situ keratomileusis

Establishing an Animal Model of Cytomegalovirus Keratouveitis in Rats: Broad Infection of Anterior Segment Tissue by Cytomegalovirus

Purpose

Considering the difficulty of obtaining adequate biological tissue in clinical practice, we established an animal model of cytomegalovirus (CMV) keratouveitis in rats and investigated the viral infection sites and corresponding imaging and histopathological features.

Methods

Subconjunctival injection and topical use of dexamethasone were used to induce ocular immunosuppression in rats followed by intracameral inoculation of murine cytomegalovirus (MCMV). The clinical manifestations, intraocular pressure (IOP) and imaging changes were observed. Infected eyes were further examined by immunofluorescence, light microscopy, and electron microscopy. MCMV RNA was detected by reverse transcription-polymerase chain reaction.

Results

Typical keratouveitis occurred in the experimental rats and was characterized by corneal edema, keratic precipitates, and iridocyclitis with increased IOP. Corneal endothelial lesions displayed as “black holes,” enlarged intercellular gaps, and high-intensity cellular infiltration by confocal microscopy, consistent with the pathological changes of “ballooning degeneration,” endothelial cell detachment, and inflammatory cell infiltration. Mitochondrial edema was the most prominent organelle lesion in endothelial cells. Trabeculitis, mechanical obstruction of Schlemm's canal, and anterior chamber angle stenosis accounted for elevated IOP. Inflammation of the iris and ciliary body tended to transform into a chronic form. Immunofluorescence revealed that corneal endothelial cells, iris cells, trabecular meshwork cells, and monocytes could be infected by MCMV. MCMV RNA was found in the anterior segments after infection.

Conclusions

CMV can widely infect anterior segment tissue, including the corneal endothelium, iris, and trabecular meshwork, in vivo, inducing the corresponding clinical manifestations. Corneal endotheliitis and hypertensive anterior uveitis could be the specific stage of anterior segment infection of CMV.

Acute interface fluid syndrome after laser in situ keratomileusis in a case of cytomegalovirus (CMV) endotheliitis and secondary glaucoma

Cytomegalovirus (CMV) can cause recalcitrant recurrent keratouveitis and secondary glaucoma. We report a case of chronic recurrent anterior uveitis with secondary glaucoma presenting with acute visual loss and interface fluid 9 years after laser in situ keratomileusis. Based on clinical presentation, a viral aetiology was suspected. Aqueous tap was positive for CMV-DNA by real-time quantitative PCR of the aqueous humour. The patient was treated with systemic antivirals, topical corticosteroids and antiglaucoma medications. The interface fluid resorbed rapidly. The intraocular pressure (IOP) was controlled by trabeculectomy. There was no further corneal deterioration at 7-month follow-up and the IOP had also stabilised. We believe this is only the third reported case of CMV-related interface fluid syndrome. This case highlights the role of quantitative PCR analysis for establishing viral aetiology in recurrent unilateral hypertensive anterior uveitis and reports the unusual finding of interface fluid which resolved after starting systemic antiviral therapy.

Pathobiology and treatment of viral keratitis

Keratitis is one of the most prevalent ocular diseases manifested by partial or total loss of vision. Amongst infectious (viz., microbes including bacteria, fungi, amebae, and viruses) and non-infectious (viz., eye trauma, chemical exposure, and ultraviolet exposure, contact lens) risk factors, viral keratitis has been demonstrated as one of the leading causes of corneal opacity. While many viruses have been shown to cause keratitis (such as rhabdoviruses, coxsackieviruses, etc.), herpesviruses are the predominant etiologic agent of viral keratitis. This chapter will summarize current knowledge on the prevalence, diagnosis, and pathobiology of viral keratitis. Virus-mediated immunomodulation of host innate and adaptive immune components is critical for viral persistence, and dysfunctional immune responses may cause destruction of ocular tissues leading to keratitis. Immunosuppressed or immunocompromised individuals may display recurring disease with pronounced severity. Early diagnosis of viral keratitis is beneficial for disease management and response to treatment. Finally, we have discussed current and emerging therapies to treat viral keratitis.

Corneal Refractive Surgery in Patients with a History of Herpes Simplex Keratitis: A Narrative Review

The incidence of herpes simplex keratitis (HSK) in patients following corneal refractive surgery is higher than in the general population, and several case reports of ocular morbidity in HSK infection following corneal refractive surgery have been published. HSK is listed by the American Academy of Ophthalmology as a relative contraindication to corneal refractive surgery, although specifics have not been further elucidated. This review summarizes the current literature regarding reactivation of HSK following corneal refractive surgery and provides a guideline for considering corneal refractive surgery in a patient with a previous history of HSK. Based on the current literature, we recommend that corneal refractive surgery is appropriate for patients with a history of HSK without multiple recurrences who have had no evidence of disease for at least one year. In addition to a thorough history and physical examination, we also recommend these patients begin 400 mg twice daily of oral acyclovir or valacyclovir 500 mg once daily for two weeks prior to surgery and continue this regimen for at least two weeks postoperatively or while on topical steroids.

Incidence and Risk Factors of New Onset Endotheliitis After Cataract Surgery

Purpose

The purpose of this study was to report the characteristics of new-onset endotheliitis after cataract surgery and to identify contributing risk factors.

Methods

In this single-center study, we retrospectively reviewed the clinical records of all patients who underwent uneventful cataract surgery in the Eye Hospital of Wenzhou Medical University between January 2015 and December 2016. Postoperative endotheliitis cases were identified by screening of keywords and individually verified by a cornea specialist. Endotheliitis rates and 95% confidence intervals (CI) were calculated. Cox proportional hazard regression analysis was used to investigate the association between endotheliitis and associated factors.

Results

A total of 20,743 cataract surgeries were performed. Fifty-nine eyes developed endotheliitis after cataract surgery, with an incidence of 0.28%. The mean interval between surgery and first record of endotheliitis was 24.51 ± 9.50 days (range, 5 to 45 days); 45 (76.27%) cases of endotheliitis developed within 30 days. The multiadjusted hazard ratio (HR) associated with increased risk of endotheliitis was 16.1 (95% CI, 3.9 to 66.9; P < 0.001) for patients 76 years of age or older and 10.2 (95% CI, 2.4 to 43.2; P = 0.002) for those 66 to 75 years of age compared with those 65 years of age or younger. Endotheliitis was also associated with history of diabetes mellitus (HR, 1.9; 95% CI, 1.1 to 3.2; P = 0.026).

Conclusions

This study found the incidence of endotheliitis after cataract surgery to be 0.28%. Diabetes mellitus and old age are major risk factors for developing endotheliitis.