Evaluation of Contrast Agents for Enhanced Visualization in Optical Coherence Tomography

Abstract

To identify and evaluate the use of contrast agents in optical coherence tomography (OCT) for ophthalmic applications. Three agents-prednisolone acetate (PA), triamcinolone acetonide (TA), and lipid-based artificial tears (LBAT)-were tested in cadaveric porcine eyes imaged with hand-held spectral-domain OCT (SD-OCT). Anterior segment imaging was performed in triplicate with each agent at three sites: corneal epithelial surface, corneal wound interface, and anterior chamber. OCT characteristics of the three agents at each ocular site were analyzed. Quantitative intensity (i.e., brightness) analysis was performed with image analysis software. Institutional review board approval was obtained for imaging in human subjects undergoing cataract surgery. PA was applied to the corneal surface, and SD-OCT imaging was performed of the corneal surface and wound interface immediately after cataract surgery. All agents provided increased reflectivity. PA and LBAT showed a smooth bright reflectivity profile, whereas TA had a granular profile. Improved visualization of tissue interfaces was noted. Maximum and mean intensity of reflectance were higher for all agents compared with controls (P < 0.05). PA showed topical and wound interface contrast enhancement in human subjects after cataract surgery. Significant OCT contrast enhancement was achieved with improved visualization of tissue interfaces. Each agent had a unique reflectivity profile. Future applications of OCT contrast agents might include evaluation of wound stability, intraocular fluidics, and ocular surface disease.