Keratitis outlook may improve with LDPK

Take-home message: Large-diameter penetrating keratoplasty for infectious keratitis may warrant a more prominent place in the treatment paradigm, suggest results of a retrospective chart review.

By Nancy Groves; Reviewed by Danielle Trief, MD

New York-Large-diameter penetrating keratoplasty (LDPK) is usually considered a “last resort” procedure for patients with severe infectious keratitis.

However, the procedure can have favorable long-term visual outcomes and should be a more frequently suggested option, indicate results from a recent retrospective chart review.

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“[More than] 70% of our patients ultimately had clear grafts, 85% had structural integrity, and 71% had improvement in their visual acuity,” said Danielle Trief, MD. “Those results are encouraging, but physicians should know that half of the patients required a repeat transplant, so it does take a lot of time and effort and maybe more surgery to get to that endpoint.”

Physicians should also be aware that, in this review, prognostic indicators of better outcomes included better preoperative visual acuity and infectious etiology.

Outcomes analysis

Investigators at the New York Eye and Ear Infirmary, where Dr. Trief was a cornea fellow, reviewed records of all eyes with culture-proven infectious keratitis that underwent LDPK (defined as 10 mm or greater) at the facility from January 2004 to December 2014. The analysis included 41 eyes of 41 patients. Outcome measures were visual acuity (converted to LogMAR), complications, and graft failure rates, and all patients had at least 3 months of follow up.

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The surgical technique for all patients was similar to that of regular penetrating keratoplasties but with modifications, including a conjunctival peritomy, a hand-held trephine, and excision 0.5 to 1 mm outside of the infected tissue. At least 16 interrupted sutures using 9-0 or 10-0 nylon were used to strengthen the wound integrity. If a cataract was present, it was not removed at the time of surgery unless the capsule was violated.

Next: Breakdown of infectious etiology

Statistical analysis showed that graft size ranged from 10 to 16 mm (median 11 mm). Follow-up times were from 3 to 105 months (median 27 months).

Structural integrity was maintained in 35 eyes, Dr. Trief noted. However, 21 of the total 41 patients required a repeat transplant or implantation of an artificial cornea (Boston Keratoprosthesis [KPro], Massachusetts Eye and Ear). Ultimately, 30 patients had a clear graft or stable KPro.

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Seventy-one percent of eyes had improved final best-corrected visual acuity (BCVA) compared with their presenting acuity, and final BCVA was 20/50 or better in 34%.

“Initial vision was predictive of the final vision (p = 0.002),” said Dr. Trief, who joined the staff of Columbia University College of Physicians and Surgeons in September as an assistant professor of ophthalmology.

Breakdown of infectious etiology

Acanthamoeba was the most commonly found organism, present in 12 of the 41 eyes. Further, the visual acuity outcomes varied by etiology. The eyes infected by Acanthamoeba had the best results, possibly because the wide excision helped eradicate the organisms, Dr. Trief said.

The two patients whose infections were caused by herpes simplex virus had the worst outcomes. Overall, the initial infection was eradicated in 85% of patients following LDPK.

Another interesting finding was that graft size did not influence final visual acuity, Dr. Trief said.

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“It didn’t seem to matter if your graft was 10 mm or 16 mm,” she said, adding that some studies have shown that larger graft sizes lead to less postoperative astigmatism and cylinder, a factor that could have been in play with these patients.

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However, the eyes with larger graft size had higher rates of development or progression of glaucoma (p = 0.025). This is likely because the larger grafts affect the angle of the eye, altering the dynamics of drainage and IOP. Half of the patients in this review developed glaucoma or experienced progression of disease postoperatively. Because of this risk, LDKP patients should be followed closely on a long-term basis.

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Danielle Trief, MD

E: dtrief@gmail.com

This article is based on Dr. Trief’s presentation at the 2015 meeting of the American Society of Cataract and Refractive Surgery. A manuscript is being prepared for publication. Dr. Trief did not report any relevant disclosures.