Multi-meridian corneal imaging of air-puff induceddeformation for improved detection of biomechanicalabnormalities

摘要

Corneal biomechanics play a fundamental role in the genesis andprogression of corneal pathologies, such as keratoconus; in cornealremodeling after corneal surgery; and in affecting the measurementaccuracy of glaucoma biomarkers, such as the intraocular pressure(IOP). Air-puff induced corneal deformation imaging revealsinformation highlighting normal and pathological corneal response to anon-contact mechanical excitation. However, current commercial systemsare limited to monitoring corneal deformation only on one cornealmeridian. Here, we present a novel custom-developed swept-sourceoptical coherence tomography (SSOCT) system, coupled with a collinearair-puff excitation, capable of acquiring dynamic corneal deformationon multiple meridians. Backed by numerical simulations of cornealdeformations, we propose two different scan patterns, aided by lowcoil impedance galvanometric scan mirrors that permit an appropriatecompromise between temporal and spatial sampling of the cornealdeformation profiles. We customized the air-puff module to provide anunobstructed SSOCT field of view and different peak pressures,air-puff durations, and distances to the eye. We acquiredmulti-meridian corneal deformation profiles (a) in healthy human eyesin vivo, (b) in porcine eyes ex vivo under varying controlled IOP, and (c) ina keratoconus-mimicking porcine eye exvivo. We detected deformation asymmetries, as predicted bynumerical simulations, otherwise missed on a single meridian that willsubstantially aid in corneal biomechanics diagnostics and pathologyscreening.