Purpose To report the long-term outcomes of the Boston type I keratoprosthesis (Kpro) in eyes with prior herpes simplex virus (HSV) keratitis.

Methods Retrospective review of all Kpro procedures performed by a single surgeon from 1 May 2004 to 1 January 2015.

Results 13 of 173 Kpro procedures were performed in 11 eyes with prior HSV keratitis. There was not a significant difference in the percentage of eyes with and without prior HSV keratitis with preoperative (9% vs 8%, p=1.00) or postoperative (57% vs 60%, p=1.00) corrected distance visual acuity (CDVA) ≥20/200 or in the percentage of contralateral eyes with preoperative CDVA ≥20/50 (55% vs 30%, p=0.18). While several postoperative complications occurred approximately twice as often in eyes with prior HSV keratitis, including persistent epithelial defect (63.6% vs 34.1%; p=0.10), corneal infiltrate (27.3% vs 12.3%; p=0.17) and sterile vitritis (18.2% vs 9.4%; p=0.31), only cystoid macular oedema (45.5% vs 12.3%; p=0.01) was significantly more common. Similarly, while the Kpro retention failure rate in eyes with prior HSV keratitis was twice than that in eyes without it (0.15 vs 0.07 per year), the difference was not statistically significant (p=0.09).

Conclusion As greater than half of patients with unilateral HSV keratitis undergoing Kpro implantation have CDVA ≥20/50 in the contralateral eye, and as the Kpro retention failure rate in eyes with prior HSV keratitis is twice than that in eyes without prior HSV keratitis, caution should be exercised when considering Kpro implantation in these patients.