Long-Term Outcomes Of Boston Type I Keratoprosthesis As Primary Penetrating Corneal Procedure

To report the long-term outcomes of the Boston type I keratoprosthesis (Kpro) as the primary penetrating corneal procedure in patients with high risk of penetrating keratoplasty (PK) failure.

A retrospective analysis of all Kpro procedures performed by a single surgeon (AJA) at the Stein Eye Institute between May 2004 and December 2022

Postoperative outcomes (corrected distance visual acuity (CDVA), retention and complications) were compared between Kpro procedures performed in eyes as the primary penetrating corneal procedure (no prior PK) and eyes with prior PK.

The most common indication in eyes with no prior PK was limbal stem cell deficiency (15 eyes, 37.5%). Comparing eyes with no prior PK to eyes with prior PK, preoperative glaucoma was significantly less common (40% vs. 77%, p<0.001) and the postoperative follow-up was similar (40.5+37.9 mo vs. 43.5+46.7 mo; p=0.83). While there was no significant difference in the % of CDVA ≥20/200 between procedures in eyes with no prior PK and prior PK at 5 years (78% vs 53%; p=0.52), the % at 10 years was higher in the no prior PK group (100% vs 52%; p=0.03). Also, while the incidence of retention failure was higher in the no prior PK group (0.127 vs 0.073 per eye-year (HR: 1.69), the difference was not significant in the multivariate analysis (HR: 1.2). 

Boston type I keratoprosthesis implantation as the primary penetrating corneal procedure results in a significant improvement in CDVA in the majority of eyes who retained the Kpro through 10 years after surgery. Despite a higher rate of persistent epithelial formation and sterile necrosis in eyes with no prior PK, there was no significant difference in the incidence of retention failure between groups.