Posterior Segment Complications and Impact on Long-Term Visual Outcomes in Eyes with a Type 1 Boston Keratoprosthesis

Purpose: To determine the spectrum of retinal complications (RCs) in a cohort of eyes with a type 1 Boston keratoprosthesis (KPro). Methods: All patients (36 eyes of 31 patients) who received a type 1 Boston KPro from January 2004 to December 2015 at the University of California, Davis, were included. Electronic medical records were reviewed for relevant clinical data. Demographic information, initial corneal diagnosis, postoperative course, posterior segment complications, preoperative and final visual acuity were tabulated and analyzed. Results: Posterior segment complications after type 1 Boston KPro were identified in 56% of eyes (n = 20). They included retinal detachment (n = 11; 31%), retroprosthetic membrane (n = 10; 28%), endophthalmitis (n = 7; 19%), cystoid macular edema (n = 5; 14%), epiretinal membrane (n = 4; 11%), vitreous hemorrhage (n = 2; 6%), choroidal detachment (n = 2; 6%), retinal vein occlusion (n = 1; 3%), and macular hole (n = 1; 3%). During the average follow-up period of 53.8 months (median, 57.1 months; range, 1.8-108.7 months) after type 1 Boston KPro, final best-corrected visual acuity improved by a mean of 0.12 logarithm of the minimum angle of resolution (LogMAR) units (range, 22.26 to +2.26) overall. The proportion of eyes with final best-corrected visual acuity better than 20/200 was 2 of 20 (10%) in the group with RCs, in contrast to 7 of 16 eyes (44%) noted among eyes without RCs. Conclusions: Long-term visual outcomes in eyes after type 1 Boston KPro may depend, in part, on maintaining a healthy posterior pole. Retinal detachment, in particular, may represent a threat to ultimate visual functioning. Regular examination of the peripheral fundus is recommended.