Clinical evaluation of deep anterior lamellar keratoplasty using glycerol-cryopreserved corneal tissues for refractory herpetic stromal keratitis: An observational study

Corneal Graft Success Rates in HSV Keratitis: A Systematic Review

Herpes Simplex Virus (HSV) has worldwide prevalence. The primary objective of this systematic review was to compare penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) regarding the efficacy and complications of the treatment of corneal scarring caused by herpes simplex keratitis. Out of the 469 articles identified during the combined search of the literature based on the PubMed and Cochrane libraries, 10 retrospective and 2 prospective studies published from January 2010 to December 2019 were included. The study outcomes indicated that both surgical approaches resulted in a comparable improvement of visual acuity (VA). However, DALK demonstrated fewer complications in the majority of studies. Higher graft survival rates were associated with higher acyclovir (ACV) doses (above 800 mg/day), topical steroid and antibiotic drops. In conclusion, in terms of postoperative VA, both PK and DALK demonstrate comparable efficacy. However, DALK, which is applied in less severe HSK cases, is associated with fewer complications and better graft survival rates. High dosages of ACV, topical steroids and antibiotics contribute significantly to improved postoperative outcomes.

Surgeon Preference for Keratoplasty Techniques and Barriers to Performing Deep Anterior Lamellar Keratoplasty

PURPOSE

To identify barriers and facilitators to adopting deep anterior lamellar keratoplasty (DALK) for nonendothelial corneal pathology.

METHODS

An anonymous survey consisting of 22 multiple choice and free text questions was designed to gather information on demographic factors of surgeons and DALK surgical practices. The survey was emailed to members of the kera-net, a global online corneal surgeon/surgery platform.

RESULTS

A total of 100 surgeons completed the survey, most of whom practice in the United States (73%). Most surgeons (89%) reported performing DALK. Surgeons who did not learn DALK during fellowship (34%) tended to be in practice for higher numbers of years (P < 0.001). Surgeons in private practice are more likely to perform DALK versus those in other settings (92.7% vs. 80.8%, P = 0.087). Surgeons performing more corneal surgeries (at least 100 per year) are more likely to perform DALK than those who perform fewer than 100 per year (52% vs. 14%, P = 0.01). Surgeons who perform Descemet membrane endothelial keratoplasty are more likely to perform DALK than those who do not (81.7% vs. 18.3%, P = 0.014). There was also a positive correlation between PK and DALK surgical volumes (Spearman rank correlation coefficient = 0.57, P < 0.001). The main reasons for surgeon preference for DALK over PK were a desire to preserve the endothelium, intraoperative safety, and decreased complications. Longer surgical time and low patient volume were cited as barriers to adoption of DALK.

CONCLUSIONS

Alterations in DALK technique that reduce surgical time and providing more learning opportunities for DALK might improve adoption.

Ocular surgery after herpes simplex and herpes zoster keratitis

PURPOSE

The recurrence of herpetic stromal keratitis (HSK) and herpes zoster ophthalmicus (HZO) has been reported after a variety of ocular surgeries. The aim of this study was to review the evidence on the preventive methods employed in the perioperative period in patients having undergone HSK/HZO.

METHODS

The PubMed and Web of Science databases were the main resources used to conduct the medical literature search. An extensive search was performed to identify relevant articles concerning the prophylaxis against and risk of HSK/HZO recurrence in patients undergoing ocular surgery up to December 31, 2019.

RESULTS

The disturbance of the corneal nerve plexus occurs during several ocular surgeries including penetrating keratoplasty, lamellar keratoplasty, corneal cross-linking, cataract surgery, as well as photorefractive and phototherapeutic procedures. Such trauma, as well as modulation of the ocular immunological response caused by steroids applied postoperatively, might engender the HSK/HZO reactivation which is not uncommon. There is strong evidence that oral prophylaxis should be recommended just after surgery in patients undergoing penetrating keratoplasty and having suffered from HSK/HZO. For other types of surgeries, the evidence is less compelling; nevertheless, a period of disease quiescence and oral prophylaxis should still be considered.

CONCLUSIONS

Within the article, we discuss the available evidence for HSK/HZO prophylaxis in ocular surgery. Additional studies would be required to define the real risk of HSK/HZO recurrence following eye surgeries, and particularly cataract surgery, and to confirm the utility of perioperative HSK/HZO prophylaxis.

Approaches toward enhancing survival probability following deep anterior lamellar keratoplasty

The greatest advantage of deep anterior lamellar keratoplasty over full-thickness corneal transplantation is the elimination of graft failure caused by endothelial rejection. Despite this advantage, a deep anterior lamellar keratoplasty graft can fail because of several factors, such as complications related to the donor-recipient interface, graft epithelial abnormalities, graft vascularization, stromal graft rejection, and recurrence of herpetic keratitis. Increased deep anterior lamellar keratoplasty graft survival is mainly built upon optimization of the ocular surface to provide a hospitable environment for the graft. Any predisposing factors for graft epithelial abnormalities, corneal neovascularization, and preexisting vernal keratoconjunctivitis should be identified and treated preoperatively. Prompt recognition and appropriate treatment of interface-related complications and stromal graft rejection usually result in good anatomic outcomes, with no detrimental effects on vision.