Abstract
Purpose: :
To identify possible risk factors for retroprosthetic membrane formation in eyes following implantation of the Boston Keratoprosthesis at University of California, Davis.
Methods: :
We performed a retrospective chart review of 47 Type I Boston Keratoprostheses (KPro) implanted from May 29, 2004 to October 24, 2008 at UC Davis. 35 eyes of 30 individual patients were analyzed for retroprosthetic membrane (RPM) formation with an average follow-up time of 17 months. Factors that were considered included incidence of formation of RPM, preoperative diagnosis, concomitant procedures at the time of surgery, pseudophakic vs aphakic Kpro, presence of pre-existing glaucoma, and pre-existing inflammatory conditions.
Results: :
In total, 14/35 (40%) eyes developed a RPM. 9/14 eyes had pre-existing glaucoma compared to 13 of the remaining 21 eyes (64% vs. 62%) . 3/35 eyes were implanted with an aphakic Kpro, and of those 2/3 developed a RPM. The same number of eyes (2) carried the diagnosis of aniridia in the RPM forming group compared with the non-RPM forming group. However, 5/14 eyes with RPM formation diagnosed with either an autoimmune or infectious condition prior to surgery compared to 2 of the remaining 21 eyes (36% vs. 9%). With regard to other procedures performed at the time of surgery, 12/35 eyes in total underwent an additional procedure, the most common of which was cataract extraction with IOL placement. Of those eyes that underwent a concomitant procedure, 6/12 (50%) developed a RPM.
Conclusions: :
• Formation of a RPM is a common complication following implantation of the Boston KPro.• The presence of pre-existing inflammatory or infectious conditiona, performance of a concomitant procedure, and implantation of an aphakic Kpro seemed to correlate with higher incidence of RPM formation in our retrospective review.• The presence of pre-existing glaucoma and aniridia, did not seem to have an impact on formation of RPM based on our data.• As implantation of the Boston Kpro has shown to be a viable procedure for improvement of vision in eyes that have otherwise failed traditional corneal transplantation, additional research is warranted to delineate the factors predisposing to RPM formation and to determine methods to prevent and effectively treat RPM formation.
Keywords: keratoprostheses • cornea: clinical science • cell membrane/membrane specializations