Surgical anatomy of the small animal eye - 3D reconstruction and ablation effect

Abstract

Purpose : Retinal prostheses help to restore vision in patients with degenerative retinal diseases, and require safe insertion. To prevent intra-/postoperative complications, e.g. retinal tearing and detachment, we performed an anatomical, histological study to describe safe insertion sites into the eye in mice, rats, and rabbits as well as in vivo experiments to observe the effect of laser- and cryo-ablation on the insertion sites. We pursue a better understanding of the surgical anatomy of the insertion sites and surgical feasibility of the implantation of retinal stimulators.

Methods : Four 15-28 weeks C57BL/6J wild-type(wt) mouse eyes, four 12-16 weeks rd10 mouse eyes, six 28 weeks Brown Norway rat eyes and twelve Chinchilla Bastard rabbit eyes went under histological processing. Three-dimensional (3D) data sets were created with two approaches: One was to create a rotationally symmetric 3D model of the eyeball by rotating a central sagittal section through the corneal apex and posterior retinal pole 360°. The second was that acquired images were subjected to image registration to align multiple scenes into one integrated image. The data was also used to reconstruct the eyes' anatomy in a virtual reality platform.
Laser- and cryo-ablation were performed in six wt mice, six rd10 mice, six Brown Norway rats and six Chinchilla Bastard rabbits. The effect of ablation was examined after 3 weeks by funduscopic effect control and histological processing of the treated areas.

Results : 3D models of mouse, rat and rabbit eyes were successfully established. We observed atrophy of the inner retinal layers as an effect of laser- and cryo-ablation. No retinal detachment occurred in the treated areas.

Conclusions : 3D models of small animal eyes can help to simulate surgical interventions of the implantation procedure of retinal stimulators. Laser- and cryo-ablation of the insertion sites may greatly contribute to a successful implantation procedure. These projects lead to safer implantation of microsystems into the eye.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

3D projections of the eyeball. 1(a)wt mouse eye, (b)rd10 mouse eye, (c)albino rat eye, (d)rabbit eye. The models were reconstructed from rotation of the equatorial sections. 2 from images stack for rd10 mouse. (a) (b) are from a different angle of projection observed.

 

Histological evaluation of rd10 mouse eyes 3 weeks after laser-/cryo-coagulation(HE, x2,5). Blue boxes mark the atrophy of the inner retina layers.