Techniques for processing eyes implanted with a retinal prosthesis for localized histopathological analysis: Part 2...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Histology

Background:

• Retinal prostheses are emerging for blindness treatment, necessitating safety evaluations.
• Metal components in implants hinder traditional histological analysis of adjacent eye tissues.
• Assessing localized damage from retinal tack insertion has been challenging.

Purpose of the Study:

• To develop and describe a reliable histological technique for evaluating eye tissue adjacent to epiretinal implants with metal tacks.
• To overcome limitations of traditional histology with hard metal components in delicate ocular tissues.
• To enable assessment of tissue integrity and cytoarchitecture around the retinal tack in situ.

Main Methods:

• Modified a technique used for cochlear implants to process delicate eye tissues.
• Embedded fixed eye tissue with implant and metal tack in epoxy resin.
• Ground, polished, stained, and imaged embedded samples at incremental depths.

Main Results:

• Successfully visualized the eye tissue directly adjacent to the metal tack.
• Demonstrated reliable assessment of tissue integrity and cytoarchitecture.
• Overcame the inability of traditional histology to cut metal objects.

Conclusions:

• The developed epoxy resin embedding and grinding technique is effective for histological assessment of eye tissue around retinal implant tacks.
• This method is vital for preclinical safety evaluation of retinal prostheses.
• Enables detailed examination of localized tissue responses to epiretinal implants.