Donor Corneal Transplantation vs Boston Type 1 Keratoprosthesis in Patients with Previous Graft Failures: A Retrospective Single Center Study (An American Ophthalmological Society Thesis)

Abstract

Purpose: To compare short-term outcomes of repeat penetrating keratoplasty (PK) to those of Boston type 1 keratoprosthesis (KPro). Our hypothesis was that visual outcomes were superior for KPro compared to PK.

Methods: This is a retrospective, nonrandomized, intermediate-term case series. Consecutive adults with one or more failed PKs who underwent either PK or KPro between January 2008 and December 2010 were included. Demographics, indication for the initial PK, comorbidities, concomitant procedures, and complications were considered. Only one procedure in each eye was included. All KPro procedures were retained in the analyses.

Results: Fifty-three patients underwent PK and 27 received KPro. Mean follow-up was 19.5 months in the PK group and 16.5 months in the KPro group. KPro eyes had worse mean preoperative vision (hand motions vs counting fingers, P=.01) and more comorbidities. In the postoperative period, 35% of PK eyes and 45% of KPro eyes attained best-ever visual acuity of 20/70. Forty-seven percent of PK eyes vs 40% of KPro eyes were able to retain this visual acuity. Two-year rate of failure to retain visual acuity better than the baseline was higher for PK eyes, though not at a statistically significant level (hazard ratio [HR]=1.67; 95% CI, 0.78-3.60; P=.19). Two-year cumulative rate of graft failure (loss of clarity for PK and removal/replacement for KPro) was higher for PK eyes (HR=3.23; 95% CI, 1.12-9.28; P=.03). Retinal detachment, endophthalmitis, and glaucoma rates were similar (P=.6 for all).

Conclusions: These results demonstrate less frequent graft failure, greater visual improvement, and greater likelihood of maintaining the visual improvement in KPro eyes vs PK.

FIGURE 1

Boston type 1 keratoprosthesis is a 3-piece collar button device with an anterior and a posterior plate as well as a titanium locking c-ring.

FIGURE 2

Slit-lamp appearance of a Boston type 1 keratoprosthesis in situ.

FIGURE 3

Mean preoperative and postoperative logMAR visual acuity at various postoperative time points (in months) in patients who underwent successive donor corneal transplant (PK) or Boston type1 keratoprosthesis (KPro) for previously failed PK in a retrospective sample at a single, tertiary care institution.

FIGURE 4

Mean change in vision (in logMAR) from preoperative values at various postoperative time periods (in months) in patients who underwent successive donor corneal transplant (PK) or Boston type1 keratoprosthesis (KPro) for previously failed PK in a retrospective sample at a single, tertiary care institution.

FIGURE 5

Preoperative visual acuity (upper), best-ever postoperative vision attained (middle), and visual acuity measured at the last examination (lower) in patients who underwent successive full-thickness corneal transplant (PK) vs Boston type 1 keratoprosthesis (KPro) for previously failed PK in a retrospective sample at a single, tertiary care institution. CF, counting fingers; HM, hand motions; LP, light perception; NLP, no light perception.

FIGURE 6

Kaplan-Meier survival curve demonstrating the proportion of eyes that were able to retain the original corneal transplant at various time points during a 2-year postoperative follow-up period, in patients who underwent a successive full-thickness corneal transplant (PK) vs Boston type 1 keratoprosthesis (KPro) after having failed one or more PK procedures in a retrospective sample at a single, tertiary care institution. Failure to retain graft clarity or avoid a successive transplant was significantly more rapid in PK eyes as compared to KPro eyes (HR=3.23; 95% CI, 1.12–9.28; P=.03).