Optical beam scanner with reconfigurable non-mechanical control of beam position, angle, and focus for low-cost whole-eye OCT imaging

Abstract

Whole-eye optical coherence tomography (OCT) imaging is a promising tool in ocular biometry for cataract surgery planning, glaucoma diagnostics and myopia progression studies. However, conventional OCT systems are set up to perform either anterior or posterior eye segment scans and cannot easily switch between the two scan configurations without adding or exchanging optical components to account for the refraction of the eye’s optics. Even in state-of-the-art whole-eye OCT systems, the scan configurations are pre-selected and cannot be dynamically reconfigured. In this work, we present the design, optimization and experimental validation of a reconfigurable and low-cost optical beam scanner based on three electro-tunable lenses, capable of non-mechanically controlling the beam position, angle and focus. We derive the analytical theory behind its control. We demonstrate its use in performing alternate anterior and posterior segment imaging by seamlessly switching between a telecentric focused beam scan to an angular collimated beam scan. We characterize the corresponding beam profiles and record whole-eye OCT images in a model eye and in an ex vivo rabbit eye, observing features comparable to those obtained with conventional anterior and posterior OCT scanners. The proposed beam scanner reduces the complexity and cost of other whole-eye scanners and is well suited for 2-D ocular biometry. Additionally, with the added versatility of seamless scan reconfiguration, its use can be easily expanded to other ophthalmic applications and beyond.

Long-range frequency-domain optical delay line based on a spinning tilted mirror for low-cost ocular biometry

“…For demonstrating the ability of the proposed TD biometer to record ocular biometry measurements, we employed a model eye (OCT model eye, Modell-Augen Manufaktur) comprising air-spaced cornea, crystalline lens, and layered retina, which are mimicking the human eye biometric features. We acquired measurements of the CCT, ACD and AL of the model eye with the proposed FD-ODL-based OLCR biometer and compared the obtained results with those from a custom laboratory SS-OCT system, thoroughly calibrated and previously used for pathlength measurements [ 67 – 69 ], the Lenstar LS 900 (Haag-Streit), a prime example of OLCR TD 1-D biometer, and the Anterion (Heidelberg Engineering), an example of 2-D SS-OCT biometer. We also employed a phantom made of three mostly transparent slabs comprising a glass microscope slide, a methacrylate slab, and a fused silica slab, of known thicknesses, comparable to the ocular distances of interest.…”