Corneal infections involving surgical interfaces and incisions represent high-stakes situations. Bennie H. Jeng, MD, MS discusses diagnosis and management of these challenging situations.
Reviewed by Bennie H. Jeng, MD, MS
Corneal infections involving surgical interfaces and incisions represent special situations that mandate special considerations for successful management, said Bennie H. Jeng, MD, MS. Dr. Jeng is professor and chairman, Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore. He discussed the issues and treatment approaches for corneal infections associated with corneal grafts, flaps, and surgical incisions.
“There is a high risk for progressive infection and/ or wound dehiscence in these clinical situations,” he said. “Early identification and aggressive treatment of the infection are critical, and surgical intervention might also need to be considered.”
The inflammatory response accompanying an infectious corneal ulcer in an eye that has had penetrating keratoplasty (PK) can cause endothelial cell dysfunction and subsequently graft failure. Infection can also develop around loose sutures and lead to graft loss secondary to tissue destruction or graft dehiscence.
Use of topical corticosteroids, presence of eyelid/ adnexal abnormalities or epithelial defects, and bandage contact lens wear can also lead to late infection in eyes with a full thickness graft. Management of corneal infections in post-PK eyes includes obtaining a specimen for culture, aggressive treatment with fortified antibiotics, and consideration for reduction in topical corticosteroid use. Suture removal is needed in cases involving suture abscess.
“If the infection is large and progressive, threatening the graft-host interface, I will try to excise it en bloc and regraft the cornea if it is not responding to medical therapy appropriately,” Dr. Jeng said.
Infections that develop in a Descemet stripping automated endothelial keratoplasty or Descemet’s membrane endothelial keratoplasty interface tend to appear a few weeks to a few months after the graft procedure and usually have a fungal etiology, with Candida being the most common pathogen. In addition to the clinical appearance, confocal microscopy can be helpful for making the diagnosis. Excision of the donor lenticule and surrounding infected tissue followed by PK provides definitive treatment, but alternative management approaches have also been described.
The latter include removing the endothelial graft, irrigating the anterior chamber with amphotericin B, and then repeating the endothelial keratoplasty procedure after the infection has been adequately treated. Intrastromal injections of antifungal agents have also been suggested.
“These infections are deep-seated, and topical and oral antifungals are not very effective treatments because they do not penetrate to the infection site when administered by these routes,” Dr. Jeng said. Infections in a deep anterior lamellar keratoplasty (DALK) interface are also most often caused by fungi.
Bacterial infections can also occur and usually develop in the setting of incomplete removal of infected stroma when the grafting was performed in an eye with active infectious keratitis. Confocal microscopy can aid in the diagnosis, and PK represents the most definitive treatment. Intrastromal injection of an antimicrobial agent can also be considered.
As for interface infections in endothelial keratoplasty (EK), infections in the DALK interface are deep-seated, and as such, topical and oral therapies are not usually adequate. “Irrigation of the interface after graft removal will probably not be effective because there will still be infected stromal tissue,” Dr. Jeng said.
Bennie Jeng, MD, MS
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This article was adapted from Dr. Jeng’s presentation at Cornea Subspecialty Day during AAO 2018. Dr. Jeng has no relevant financial interests to disclose.