Intermediate-Term and Long-Term Outcomes With the Boston Type 1 Keratoprosthesis in Aniridia

To report the intermediate- and long-term visual outcomes and complications with the Boston type 1 keratoprosthesis (KPro) for the management of aniridic keratopathy.

A retrospective chart review of 46 eyes of 34 patients (20 females and 14 males) with aniridic keratopathy who underwent Boston type 1 KPro surgery by a single surgeon from 2004 to 2012 with minimum 2-year follow-up was conducted. Preoperative, intraoperative, and postoperative parameters were collected and analyzed. The primary outcome was the change in best-corrected visual acuity. Secondary outcomes included the rate of retroprosthetic membrane formation, glaucoma progression, glaucoma tube revisions, and KPro retention.

Mean age of the patients was 43.5 ± 19.8 years with a mean follow-up period of 4.5 ± 1.6 years (range 2-7.4 years). Thirty-four eyes (74%) had previously failed keratoplasty. Thirty-five eyes (76%) previously underwent ocular surface stem cell transplantation, specifically a keratolimbal allograft. Within the first 6 months postoperatively, 74% (34/46) of patients experienced a gain of ≥2 lines of vision. Overall, there was a gain of ≥2 lines of vision in 43.5% (20/46) of patients at last follow-up. The rate of retroprosthetic membrane formation was 61%, the rate of glaucoma onset/progression was 26%, the rate of tube revision was 31%, and the KPro retention rate was 87%.

This study confirms that initial visual improvement in aniridic keratopathy cases occurs at a high rate with the Boston type 1 KPro but also found progressive loss of these initial visual improvements.