Very high frequency ultrasound imaging of the cornea used in an animal model of corneal toxicity.

Abstract

Abstract: : Purpose:To develop a new tool for clinical visualization of the ocular surface. We compared images obtained using a very high frequency (VHF) ultrasound with histological analyses of rabbit cornea treated with 0.01% benzalkonium chloride (BAC) until epithelial toxicity. Methods:A spherical focused transducer with a frequency of 60 MHz was used in a pulse–echo mode, mechanically scanned in three dimensions using a step by step motor and specially designed to explore the cornea. 32 eyes from 16 rabbits were included: right eyes received 0.01% BAC twice a day while left ones served as control. After biomicroscopic exams, experimental imaging were realized at day 8, 21, 28 and 60 then immediately followed by histological and ultrastructural analyses of the cornea. Results:We obtained, using VHF ultrasound, an entire section imaging of the cornea including a double signal for the safe epithelium which disappeared at day 60. Morphological changes obtained at different time points were well correlated with histological study. Precision of corneal thickness measures was determined with an axial resolution of 25 microns. Conclusion:This preliminary study showed a non invasive, reliable technique for corneal epithelium investigation. Further studies are needed for subclinical corneal epithelial changes detection in the field of corneal toxicity induced by topical drugs.

Keywords: cornea: epithelium • imaging/image analysis: non–clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)