Impact of keratoprosthesis implantation on retinal and visual pathway function assessed by electrophysiological testing.

Abstract

To investigate the impact of Boston Type I Keratoprosthesis (BI-Kpro) implantation on retinal and visual pathway function, respectively, assessed by full-field electroretinography (ERG) and visually evoked potentials (VEPs). This is a prospective interventional longitudinal study, and patients with BI-Kpro implantation were assessed preoperatively and at 3 and 12months after surgery. ERG, flash, and pattern-reversal VEPs (15' and 60' checks) along with visual acuity (VA) were performed. A total of 13 patients (24 to 88years of age) were included. Mean baseline VA (logMAR) improved from 2.30 to 1.04 at 3months and to 1.00 at 12months. Flash VEPs were normal in 6 (46%) patients and in 10 (77%) patients at the 12-month follow-up. PVEP was non-detectable in all patients preoperatively for both check sizes. For 15' check size, 6 (46%) patients showed responses after 3 and 12months except for 1 patient with normal responses at 12months with the remaining non-detectable. For 60' checks, 11 (85%) patients had responses 3months after surgery with only 9 (70%) showing responses at 12months. Abnormal full-field ERGs were found in all patients preoperatively. Amplitude improvement was found in 10 (77%) patients from baseline to 3months and in 8 (62%) patients from the 3- to the 12-month follow-up. In this small cohort of patients with BI-Kpro implantation, a remarkable improvement on visual function quantitatively assessed by electrophysiological testing was found in the majority of cases. Visual electrophysiological testing can contribute to objectively assess functional outcomes in this population.