Speaker: Continual improvements made in keratoprostheses
NEW ORLEANS – The keratoprosthesis has been an inexpensive and safe artificial cornea for many patients in the developing world, and improvements in the design and protocol have greatly reduced complication rates, according to a presenter here.
“The Boston Keratoprosthesis (B-KPro) is implanted in a standard corneal graft and then sutured in,” Claes H. Dohlman, MD, PhD, said in the keynote lecture at Cornea Subspecialty Day preceding the American Academy of Ophthalmology meeting.
Potential complications include tissue melt, infection, glaucoma and inflammation that can cause other problems, such as retinal detachment, he said.
Claes H. Dohlman
“Tissue melt and infection are gradually being brought under control,” Dohlman said. “Daily antibiotic drops have counterintuitively been an enormous blessing in keeping infection down. It’s been reduced by 10 times over the last 2 decades.”
From 1990 to 2013, incidence of tissue melt has been reduced from 30% to 3%, bacterial infection from 10% to 1%, and retroprosthetic membrane from 50% to 0, he reported.
“My favorite antibiotic combination is Polytrim (trimethoprim sulfate and polymyxin B sulfate, Allergan); once daily is enough in most of the cases,” he said. “Only in autoimmune situations have I had to use a drop of vancomycin. We have had a patient on the Polytrim regimen for 30 years. This is after the first month of higher doses.”
Compliance with prophylaxis is usually the problem that results in fungal infections, Dohlman said, but they are usually detected early. Dohlman said he had “high hopes” for a drug-eluting contact lens in development, particularly to help with patient compliance.
Glaucoma, however, is still a problem, Dohlman said, with two-thirds of patients receiving a keratoprosthesis already having glaucoma.
“Glaucoma is the focus of our present efforts,” Dohlman said. The lack of reliable tonometry is one problem in these cases that may be addressed with a wireless device that can be implanted to monitor IOP.
“We hope in a few years we can be implanting these with the KPros,” Dohlman said.
Disclosure: Dohlman is employed at Massachusetts Eye and Ear Infirmary, which manufactures and distributes the B-KPro lens.