Battlefield-Ready Fully Handheld Anterior-Segment Optical Coherence Tomography
Abstract
More than 130,000 U.S. Veterans are permanently blind, and more than a million have low vision that affects their ability to perform necessary daily activities. One of the major causes of blindness for military Service members is injury to the eye during combat, often caused by penetrating objects (called "intraocular foreign bodies," or IOFBs) that get lodged in the eye. Timely removal of such objects is critical to avoiding long-term damage and vision loss. Unfortunately, the technologies typically used to identify the type and location of IOFBs are too bulky to bring to the battlefield, which increases both time to assessment risk for long-term vision problems for Service members in combat. The main goal of this proposal is to build the first fully handheld system based on optical coherence tomography (OCT), a technology that can locate and determine the size of IOFBs. Our objective is to develop and test a new strategy for handheld OCT that leverages existing components of field-deployable equipment to yield >10x reductions in size, weight, and power critical to enabling deployment on the battlefield and in prolonged field care settings. As a proof of concept, we will build our OCT system as an attachment to a smart phone. Hence, we will replace the typically bulky components of an OCT system (e.g., detector, display screen, and computer) with the built-in camera, screen, and internal processing power of the smartphone. Making this system is challenging for several reasons. F irst, smartphone cameras are optimized to detect visible light; however, OCT imaging is done with invisible, infrared light. To overcome this challenge, we will make a special filter that can convert infrared light into visible light. This filter will be placed between the OCT system and the camera of the smartphone. This strategy is useful to demonstrate the ability to integrate our system with existing equipment without tampering with the device (e.g., opening the phone). Second, OCT detectors require a lot of space in order to collect information at many different wavelengths (colors); typically, each wavelength is collected on a different pixel. To make the system more compact, we will introduce a new design for the OCT detector that mixes light from different wavelengths onto a single pixel. Third, OCT systems typically include expensive, power-hungry light sources and scanners to make 3D images. We propose to replace the expensive light source with a small, low-power LED and to use motion sensors built into the smartphone to replace the scanner, similar to the operation of the panorama imaging mode that exists on most smartphones today. This project consists of two Aims divided into seven total tasks. In Aim 1 (Tasks 1.1-1.3), we will develop the innovations described above and test them in the laboratory. In Aim 2 (Tasks 2.1-2.4), we will combine the innovations described above into a compact prototype, attach it to the smartphone, collect and process sample OCT images, and test the ability of the system to perform eye imaging in Veterans. The short-term outcomes of this proposal include new strategies to build compact OCT systems and a prototype OCT system that is sufficiently lightweight to deploy on the battlefield. The availability of such technology at the point of injury would greatly facilitate triage and timely removal of penetrating objects, ultimately saving vision for Soldiers injured in combat. Because OCT is frequently used to diagnose eye diseases in Veterans and the American public, the lightweight, handheld nature of this new system would make it possible for many more people to receive OCT examinations, especially those who have difficulty traveling to hospitals that have OCT instruments or sitting in front of the machine (e.g., children, bedridden patients). The long-term outcomes of this proposal include: a viable strategy to enable new forms of biochemical analysis and optical imaging on smartph
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010938
Entities
People
- Audrey K. Ellerbee Bowden
Organizations
- United States Army
- Vanderbilt University