Post-surgical visual outcome and complications in Boston type 1 keratoprosthesis

To describe the visual outcome of patients who underwent Boston type 1 keratoprosthesis (KPro1) implantation, and describe serious sight-threatening post-operative complications.

We performed an analysis of the clinical records of all patients who underwent Boston keratoprosthesis implantation (BKI)in our institution from May 2006 to February 2011.

A total of 41 eyes of 37 patients were included in the final analysis, of whom 22 (59.45%) were male and 15 were (40.54%) female. The mean age was 56.44 years (range 2-90). The most frequent diagnoses were bullous keratopathy, autoimmune diseases, such as Stevens-Johnson syndrome (SJS)/Lyell syndrome (LS), and aniridic keratopathy. The mean number of previous keratoplasties (PK) was 2.36 (range 0-8), the mean number of previous non-PK surgeries was 1.58 (range 0-9). The mean follow-up time was 22.17 months (range 3-46). The mean best corrected visual acuity (BCVA) logMAR before surgery was 2.05 (range 1.10-2.52), and the mean best corrected visual acuity achieved after surgery was 1.16 (range 0.08- 2.70). The most frequent complication was the formation of retroprosthetic membrane (RPM) which appeared in 22 (53.65%) eyes. Of these, 6 (27.27%) appeared after another surgery. Fourteen (63.63%) RPM required treatment, an average of 1.71 (range 1-4) laser YAG applications were performed, and surgical membranectomy was performed in 3 patients. Eleven (26.82%) eyes showed chorioretinal adhesion problems, 6 (14.63%) of which occurred after follow-up of BKI surgery. Infectious complications occurred in 7 (17.07%) cases; 2 (4.87%) patients had infectious keratitis and 5 (12.19%) endophthalmitis.

Visual function improved in most patients. Those with prior multiple ocular surgeries and alterations of systemic immunity such as SJS, LS, and diabetes mellitus are at increased risk for serious sight-threatening complications, such as RPM, chorioretinal detachment and infection. Nevertheless, we consider KPro as an effective alternative in patients with multiple ocular pathology and imminent risk of rejection of a new KP.