Imaging of Surface Defects and Biofilm Formation of Extruded Keratoprostheses Using Confocal Microscopy

Abstract

 

Purpose

 

The goal of the study was to examine surface structure and biofilm deposits on keratoprostheses (KPro) that extruded from patients secondary to Streptococcal Endophthalmitis. Confocal microscopy studies allow for fresh cultures in contrast to biofilm detection using SEM which was presented previously (De La Cruz et al, IOVS Meeting abstracts 2011 52:345).

 

Methods

 

Three keratoprostheses (2 Boston Type I and 1 Modified Osteo Odonto Keratoprothesis (MOOKP)) that extruded due to Streptococcal Endophthalmitis were stained with BacLight Live/Dead fluorescence assay and imaged with a Leica 5PS confocal microscope with 63x objective lens. Surface features of the keratoprostheses were visualized using bright field illumination. The biofilm and bacteria distribution across the entire KPro were evaluated using volumetric image sets that were captured from different regions of the keratoprostheses.

 

Results

 

Biofilm deposits were present on all three of the KPros (see Figure). Bacteria were found in higher quantities in areas of the optic with surface scratches. Surface features corresponding to machining marks were found on the 2 Boston KPros and surface scratches on both of the optical surfaces of all KPros.

 

Conclusions

 

Surface irregularities on the KPros created during fabrication allowed for more bacterial and biofilm growth. Improving surface quality of the implants might reduce the areas where bacteria and biofilm can attach to the keratoprothesis.

 

 

Figure 1: Image A (left) bright field of scratches on cylindrical face of MOOKP (right) live dead stain of same section, biofilm deposits appear in dome-like shapes; Image B (left) bright field of deep scratch in cylindrical face of MOOKP, (right) bacteria deposit in crevices of scratch; Image C (left) bright field of center anterior face of KPro#1, machining marks can been identified as concentric rings (right) organic matter deposited on anterior face of optic; Image D unidentified mark on posterior face of optic (inside anterior chamber)

 

Keywords: 575 keratoprostheses