Monitoring the progression of chemical-induced ocular injury through anterior segment optical coherence tomography (AS-OCT)

Abstract

Purpose : Existing clinical assessment methods for ocular chemical exposures are primarily qualitative examinations limited to the surface of the eye and can be subjective. Anterior segment optical coherence tomography (AS-OCT) offers a solution to this issue, allowing for non-invasive and high-resolution imaging of anterior segment structures. AS-OCT thereby provides the ability to quantify pathological changes over time, even in the presence of corneal opacity or fibrosis, which are both considerable hinderances to current methods.

Methods : Following an IACUC-approved protocol, acute injury model of chemical exposure was performed in a mouse model through topical application of a 2 mm diameter circle of filter paper soaked in 2.5 mg/mL acrolein or 1.0M NaOH to the right eye for 30 seconds. AS-OCT was performed on the cornea and iris simultaneously, before the chemical burn and up to 21 days following the burn. OCT angiography (OCTA) was performed using a custom algorithm that is designed to reconstruct the morphological and vascular features of the cornea. Corneal thickness of each eye was measured in ImageJ. Eyes were enucleated on day 21 for histology.

Results : For both chemical agents, AS-OCT/OCTA revealed corneal neovascularization and ulceration by day 21; however, the progression of injury differs significantly. Acrolein exposure initially presents with minor injury (e.g., slight corneal swelling) that apparently recovers until a rebound occurs between 14-21 days, including neovascularization and corneal thickness changes. In contrast, alkali exposure led to an immediate inflammatory response accompanied by severe corneal opacification and swelling (146%) that progressively worsened, peaking at 296% on day 14. Neovascularization was first detectable at day 7 by OCTA and encroached into the central cornea.

Conclusions : AS-OCT was able to clearly visualize the progression of chemical injury and identified qualitative and quantitative image-based biomarkers that assess injury severity and progression, validated through histology. The clinical availability of AS-OCT has the potential to enhance our understanding of ocular injury and different patterns of progression in chemical exposures to improve clinical assessment for better management and treatment development.

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