Dr Timothy Chou from Renaissance School of Medicine at Stony Brook University, New York, USA and colleagues have reported a case of Herpes Simplex Virus Stromal Keratitis and Endothelitis after Femtosecond Laser Assisted Cataract Surgery (FLACS) and Laser Astigmatic Keratotomy.
The case report has been published in the Journal of Cataract and Refractive Surgery Online Case Reports.
A 72-year-old woman underwent uneventful FLACS in the right eye, combined with superonasal and inferotemporal FSAK incisions. Two weeks later, she developed pain and decreased vision in her operated eye. Slit lamp examination revealed ulceration and infiltration in the superonasal cornea, at one of the astigmatic keratotomy sites. There was associated dense fibrinous anterior chamber reaction. Empirical management with topical antibiotics and antifungals along with a low dose steroid was given. Over a period of a few weeks, the ulcer healed, but corneal inflammation and infiltration persisted.
The patient was referred to the Cornea Speciality Centre of the Stony Brook University for management of persistent keratitis. On examination, corrected distance visual acuity was 20/50. Corneal sensation was decreased. A thickened pannus was observed extending into the superonasal cornea but the epithelium was intact. This was associated with stromal thinning and Descemet folds radiating from the superonasal to central cornea. The folds were dotted with keratic precipitates. HSV Stromal Keratitis and Endothelitis was suspected based on clinical examination and unsuccessful response to topical fortified antibiotic and antifungal medications. Empirical management with topical steroids under the cover of oral anti-viral medication was started.
Over the course of the next 3 weeks, the patient improved. The corneal vessels regressed, the lipid infiltrate resorbed, and the radiating corneal folds resolved. The corrected distance visual acuity eventually improved to 20/25. The topical steroids were tapered and stopped but oral anti-viral medication was recommended to be continued, as prophylaxis against recurrence.
Herpes Simplex Keratitis (HSK) has been known to reactivate after excimer laser ablations of the cornea. The excimer laser emits radiation of 193 nm wavelength which is in the UV spectrum. UV radiation seems to trigger HSV reactivation. Femtosecond Laser (FSL) radiation however is emitted in the near-infrared wavelength and it is unclear whether HSK activation after FSL is related to the laser wavelength.
The authors speculate that the penetration of the photo disruptive FSL energy deep into the corneal stroma during the creation of an astigmatic keratotomy incision may damage stromal nerve endings just as with excimer laser. Postoperative inflammation with prostaglandin release associated with Femtosecond Laser Assisted Cataract Surgery and topical corticosteroid use may have additionally triggered the HSK reactivation in the patient.
The authors wish to highlight the fact that the patient had no previous history of HSK but still developed reactivation keratitis after FLACS and FLAK.
"We suggest that patients undergoing FLACS or FLAK be counselled preoperatively about possible reactivation of HSK. Surgeons might wish to consider systemic antiviral prophylaxis or even avoid use of the FSL altogether in patients with actual history of HSK." conclude the authors.
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https://journals.lww.com/jcro/Fulltext/2021/01000/Herpes_simplex_virus_stromal_keratitis_and.12.aspx?context=LatestArticles