Wound healing after inverted implantation of Ferrara Ring Segments

Abstract

 

Purpose:

 

To evaluate the stromal wound healing, clinical follow-up and refraction changes in an animal model after normal and inverted intrastromal ring segments implantation.

 

Methods:

 

For an animal model we used the hen. We performed surgery for this study on 48 hens (96 eyes) and implanted one segment in each eye at 80% of the corneal thickness by mechanical method provided by Ferrara. The size of the segments was 150 micrometres , 90 degrees in arch and the shape was triangular (Ferrararing®).The eyes after surgery were divided into 2 groups as regards intrastromal ring implantation inverted or normal.We did clinical follow-up under surgery microscope. We also did transmitance and refractive measurements with two special devices. The histological analysis was done under light microscope after hematoxylin-eosin stain. SPSS 19 Statistical software was used for statistical analysis.

 

Results:

 

7 rings were implanted in an inverted way and 89 correctly. All the segments were well clinically tolerated. We did not find statistically significant differences between groups in the clinical follow-up.As regards histological analisis, in the group with the inverted implanted ring we noticed less epithelial hipoplasia over the segment and hipercellularity around the segment. However, we observed more edema in posterior stroma in this group. The refractive change after inverted implantation was smaller than in the group in which we implanted the segment in a normal way.

 

Conclusions:

 

The inverted implantation was well tolerated in our animal model without statistical clinical differences with normal implantation.The wound healing response showed that the epithelial hipoplasia is directly related to the apex of the triangular ring and the Stromal hipercellularity could be related to the tension strengths due to the shape and disposition of the rings in the stroma.  

 

Keywords: wound healing • cornea: stroma and keratocytes • refractive surgery: other technologies