Abstract
Purpose :
To evaluate and understand glaucoma visual outcomes of the Boston Keratoprosthesis type I (KPro), including risk factors and protective factors against glaucoma development.
Methods :
Retrospective cohort study of 137 eyes in 118 patients with KPro implantation between October 2008 and March 2017 with at least 6 months of follow-up. Patients without glaucoma were compared to those diagnosed with glaucoma, which included treatment with intraocular pressure (IOP)-lowering drops or glaucoma surgery. The main outcomes were glaucoma onset, indications for KPro implantation and for previous corneal grafts, and postoperative complications. Demographics, as well as visual acuity (VA), IOP and cup-to-disc ratio collected preoperatively and every 6 months postoperatively, were recorded. Descriptive statistics and incidence rates were used to compare the outcome variables.
Results :
Mean age at surgery was 61.5±15.9 years, with mean follow-up of 67.7±31.3 months. The most common indication for KPro surgery was failed graft (n=70, 51%). Of the 137 eyes, 22 (16%) did not have glaucoma. 84 (73%) of the 115 eyes with glaucoma had glaucoma prior to surgery. Of the 53 eyes undergoing KPro without prior glaucoma, 31 (59%) developed glaucoma after surgery. Post-KPro glaucoma incidence was 4.0 cases per 100 eye-years, with average onset at 2.2±1.9 years after surgery. Patients without final outcome of glaucoma were younger (P=0.049) and of male gender (P=0.012). Eyes with non-aniridic limbal stem cell deficiency (LSCD) were at lower risk of glaucoma (RR=0.2, 95% CI 0.1-0.5, P=0.013). Best postoperative LogMAR VA of the overall cohort was 1.0±1.3 at 1.2±1.8 years and mean LogMAR VA was 2.0±2.1 at last follow-up (5.7±2.7 years), with no difference between KPro eyes with and without glaucoma (P>0.05). However, mean LogMAR VA at last follow-up was worse for pre-KPro (2.1±2.1 at 5.5±2.8 years) compared to post-KPro glaucoma eyes (1.7±2.0 at 6.2±2.6 years, P=0.001). Cumulative incidence of postoperative complications at 9 years was higher in KPro eyes with glaucoma (92%) than without glaucoma (77%, P=0.035).
Conclusions :
Glaucoma is a common complication following KPro implantation. Younger patients with non-aniridic LSCD appear at decreased risk for glaucoma. Non-glaucomatous eyes do not achieve better VA, however, have less postoperative complications compared to those with glaucoma.
This is a 2020 ARVO Annual Meeting abstract.