Optical clearing of the eye using the See Deep Brain technique

Area of Science:

• Ophthalmology
• Neuroanatomy
• Histology

Background:

• Tissue clearing techniques have advanced neuronal tissue visualization.
• Optical clearing methods like See Deep Brain (SeeDB) have not been applied to ocular tissues.
• The eye, part of the central nervous system, presents unique challenges for histological analysis.

Purpose of the Study:

• To apply the See Deep Brain (SeeDB) optical clearing method to visualize intraocular structures.
• To assess the efficacy of SeeDB in achieving scleral transparency for enhanced anatomical study.
• To explore the potential for SeeDB in future topographical and pathological studies of the eye.

Main Methods:

• Human (cornea donor) and animal (chicken, mouse) eyes were fixed.
• Samples were treated with SeeDB, a water-based optical clearing method using fructose and α-thioglycerol.
• Transscleral macrophotography of the choroid was performed after clearing.

Main Results:

• Complete scleral transparency was achieved in human and chicken eyes post-SeeDB treatment.
• Macroscopical visualization of choroidal vasculature and structures was possible through the translucent sclera.
• Mice optic nerves also became transparent after SeeDB application.

Conclusions:

• The SeeDB method successfully renders the sclera transparent, enabling visualization of internal ocular structures.
• This technique facilitates 3D topographical anatomical studies of human and animal eyes.
• SeeDB holds potential for visualizing structures like choroidal ganglionic plexuses and aiding clinical-pathological correlations in intact eyes.