Abstract
Purpose :
Retroprosthetic membranes (RPM) are the most common complication after Boston keratoprosthesis type 1 (KPro) implantation. Most RPM develop during the first year after implantation, and they can be monitored if not visually significant. Visually significant RPM are treated with Nd:YAG membranectomy or surgical excision. A small subset of KPro patients develop RPM that are recurrent and require multiple interventions. The purpose of this study is to report the frequency of recurrent RPM, associated factors, and the outcomes in affected eyes.
Methods :
We performed a retrospective chart review of 172 eyes that underwent KPro implantation at the Illinois Eye and Ear Infirmary from January 2007 to November 2017. An RPM was defined as recurrent if it required two or more of the following treatments: Nd:YAG membranectomy, pars plana membranectomy, or KPro exchange. We analyzed the preoperative characteristics of these patients, their visual outcomes, and other ocular complications. Patients with less than 1 year follow up were excluded.
Results :
14 eyes (8.14%) met the inclusion criteria for our study. Patients were divided into three categories based on the primary indication for KPro implantation: non-inflammatory (78.6%, n=11), autoimmune (21.4%, n=3), and chemical injuries (0%). Mean age at implantation was 47 years (SD± 14.89). A titanium backplate was used in 78.5% of the eyes for the initial implant. Mean preoperative visual acuity was logMAR 2.4 and improved to 1.6 at the last follow-up despite the presence of recurrent RPM. An improvement in visual acuity was seen in 71% of patients. In 4 patients, vision dropped to no light perception (Table 1). The mean time to develop the first RPM was 2.28 months (SD±2.12). The mean number of YAG membranectomies performed was 1.5 per eye (range 0-5) and mean surgical membranectomies was 1.3 per eye (range 0-3). Eleven eyes (78.5%) required KPro exchange during the follow-up period. The most common associated complications were retinal detachment (50%), corneal melting (36%) and epithelial defects (36%) (Table 1).
Conclusions :
In our series, we observed that recurrent RPM is not a common complication after KPro implantation but can significantly impact outcomes. Visual improvement for these patients is limited, and most deteriorate over time. Retinal detachment after recurrent RPM is the most common vision threatening complication.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.