Intrinsic Optical Properties of Boston Keratoprosthesis.

Purpose: To benchmark the optical performance of Boston Keratoprosthesis (B-KPro).

Methods: Back focal lengths (BFL) of B-KPros for various eye axial lengths were measured using an optical bench, International Organization for Standardization-certified for intraocular lens characterization, and compared against manufacturer's specification. The modulation transfer function (MTF) and the resolution efficiencies were measured.

Three-dimensional Neuroretinal Rim Thickness and Visual Fields in Glaucoma: A Broken-stick Model.

Precis: In open-angle glaucoma, when neuroretinal rim tissue measured by volumetric optical coherence tomography (OCT) scans is below a third of the normal value, visual field (VF) damage becomes detectable.

Purpose: To determine the amount of neuroretinal rim tissue thickness below which VF damage becomes detectable.

Methods: In a retrospective cross-sectional study, 1 eye per subject (of 57 healthy and 100 open-angle glaucoma patients) at an academic institution had eye examinations, VF testing, spectral-domain OCT retinal nerve fiber layer (RNFL) thickness measurements, and optic nerve volumetric scans.

Implantable self-aligning fiber-optic optomechanical devices for in vivo intraocular pressure-sensing in artificial cornea.

Artificial cornea is an effective treatment of corneal blindness. Yet, intraocular pressure (IOP) measurements for glaucoma monitoring remain an urgent unmet need. Here, we present the integration of a fiber-optic Fabry-Perot pressure sensor with an FDA-approved keratoprosthesis for real-time IOP measurements using a novel strategy based on optical-path self-alignment with micromagnets.

Single-shot depth profiling by spatio-temporal encoding with a multimode fiber.

Computational imaging with random encoding patterns obtained by scattering of light in complex media has enabled simple imaging systems with compelling performance. Here, we extend this concept to axial reflectivity profiling using spatio-temporal coupling of broadband light in a multimode fiber (MMF) to generate the encoding functions. Interference of light transmitted through the MMF with a sample beam results in path-length-specific patterns that enable computational reconstruction of the axial sample reflectivity profile from a single camera snapshot.

Effects of gamma radiation sterilization on the structural and biological properties of decellularized corneal xenografts.

To address the shortcomings associated with corneal transplants, substantial efforts have been focused on developing new modalities such as xenotransplantion. Xenogeneic corneas are anatomically and biomechanically similar to the human cornea, yet their applications require prior decellularization to remove the antigenic components to avoid rejection. In the context of bringing decellularized corneas into clinical use, sterilization is a crucial step that determines the success of the transplantation.

Microglia Regulate Neuroglia Remodeling in Various Ocular and Retinal Injuries.

Reactive microglia and infiltrating peripheral monocytes have been implicated in many neurodegenerative diseases of the retina and CNS. However, their specific contribution in retinal degeneration remains unclear. We recently showed that peripheral monocytes that infiltrate the retina after ocular injury in mice become permanently engrafted into the tissue, establishing a proinflammatory phenotype that promotes neurodegeneration.

Optomechanical and photothermal interactions in suspended photonic crystal membranes.

We present here an optomechanical system fabricated with novel stress management techniques that allow us to suspend an ultrathin defect-free silicon photonic-crystal membrane above a Silicon-on-Insulator (SOI) substrate with a gap that is tunable to below 200 nm. Our devices are able to generate strong attractive and repulsive optical forces over a large surface area with simple in- and out- coupling and feature the strongest repulsive optomechanical coupling in any geometry to date (gOM/2π ≈65 GHz/nm). The interplay between the optomechanical and photo-thermal-mechanical dynamics is explored, and the latter is used to achieve cooling and amplification of the mechanical mode, demonstrating that our platform is well-suited for potential applications in low-power mass, force, and refractive-index sensing as well as optomechanical accelerometry.

Bonding, antibonding and tunable optical forces in asymmetric membranes.

We demonstrate that tunable attractive (bonding) and repulsive (anti-bonding) forces can arise in highly asymmetric structures coupled to external radiation, a consequence of the bonding/anti-bonding level repulsion of guided-wave resonances that was first predicted in symmetric systems. Our focus is a geometry consisting of a photonic-crystal (holey) membrane suspended above an unpatterned layered substrate, supporting planar waveguide modes that can couple via the periodic modulation of the holey membrane. Asymmetric geometries have a clear advantage in ease of fabrication and experimental characterization compared to symmetric double-membrane structures.