Long-term outcomes following primary versus secondary Boston keratoprosthesis type 1 implantation

Anatomical and functional outcomes of Boston type I keratoprosthesis as primary penetrating corneal procedure in high-risk and non-high-risk cases

PURPOSE

To analyze the anatomical and functional results of Boston type I keratoprosthesis (B1-KPro) as a primary corneal procedure in high-risk (HR) cases and non-high-risk (NHR) cases.

METHODS

In this retrospective interventional case series, all patients who underwent B1-KPro at a single center between January 2006 and March 2021 were reviewed and identified. Cases were classified according to the primary diagnosis. Anatomical failure was considered in the case of prosthesis extrusion or phthisis bulbi. Functional failure was a postoperative corrected distance visual acuity (CDVA) ≥ 1.3 LogMAR (≤ 0.05 decimal) at the end of the follow-up period.

RESULTS

Twenty-three eyes were included for analysis. Thirteen eyes were classified as HR and 10 as NHR. The mean age was 46.5 ± 26.5 years (5-84 years) in the HR group and 49.5 ± 26.9 years (2-78 years) in the NHR group. The mean follow-up was 42.0 ± 35.9 months (1.5-118 months) in HR and 44.8 ± 38.8 months (1-107 months) in NHR. Three eyes in the HR and none in the NHR group showed anatomical failure. Functional failure was reported in 5/13 eyes in the HR and 8/10 in the NHR group. Functional cumulative survival probability was 92% and 82% for the HR group at 1 and 2 years, respectively. In the NHR group, it was 27% at both times. No significant differences were found between groups, except for functional survival in the HR group due to better visual potential of the eyes.

CONCLUSIONS

B1-KPro as a primary corneal procedure is a valid option for visual rehabilitation in high-risk cases.

The treatment of end-stage corneal disease: penetrating keratoplasty compared with Boston type 1 keratoprosthesis

Penetrating keratoplasty (PKP) yields excellent results for restoring vision in end-stage corneal diseases. However, its success is limited to high-risk diseases such as aniridia, chemical burns, autoimmune corneal diseases, and herpetic eye disease. Boston type 1 keratoprosthesis (BKPro) offers another option to these patients. Since 1992, improvements in perioperative management and device construction have significantly increased the use of BKPro worldwide and challenged the therapeutic role of PKP in these patients. This review aims to evaluate BKPro's place in the treatment algorithm of these high-risk patients to assist surgeons' decision-making. PKP and BKPro are compared in three outcome categories: visual acuity, graft retention and failure, and complications profile. Special attention is given to comparing secondary BKPro versus repeated PKP as well as primary BKPro versus primary PKP. We conclude that secondary BKPro bears a better prognosis than repeated PKP in most high-risk patients. Similarly, primary BKPro likely confers improved outcomes over primary PKP in most high-risk recipients. However, current evidence is based on retrospective designs, and controlled prospective randomized trials are required to validate these conclusions.