Optical coherence tomography (OCT) is the gold standard for the diagnosis and monitoring of retinal and optic nerve diseases. Most clinical OCT systems are large tabletop devices that require a compliant subject, and thus are not suitable for use with infants, young children, and patients who are unable to cooperate for eye imaging (such as from physical disability or during eye examination under anesthesia). As many of these patients cannot communicate about vision disturbance or vision loss, diagnosis of disease in these patients is difficult to achieve before irrevocable vision loss occurs. One example is preterm infants at risk for retinopathy of prematurity (ROP) who make up 1.4% of the newborn population. While handheld OCT (HH-OCT) has led to significant insights into the development of ROP, the use of HH-OCT for disease screening has been limited due to the poor usability of existing commercial systems. Capturing images in awake infants with these systems is challenging, requiring specialized research staff with significant training. There is a need for a point of care, high-speed, user-friendly handheld OCT system to improve the standard of care of infants, young children, and patients who are unable to cooperate for imaging. Theia Imaging is led by a team of experts in the development HH-OCT systems. Our long-term objective is to develop a point of care, high speed, user-friendly, handheld OCT system to enable clinicians and researchers to gather much-needed OCT imaging of the retina and/or optic nerve head of their patients. This will decrease the need for examinations under anesthesia and simplify access to valuable information about the retina and optic nerve head at the time of eye care and general health care. Through the following specific aims, we will begin the process of translating such an HH-OCT system, with improved speed, ergonomics, and usability as compared to commercially available systems. Specific Aim 1: Develop a Portable, High-Speed OCT System with Ergonomic, User-Friendly Handheld Probe. We will develop a 300 kHz OCT system (the fastest medical OCT system of any kind) with a lightweight, ergonomic handheld probe. Specific Aim 2: Develop Real-Time, Workflow-Optimized OCT Capture Software. We will develop real time, OCT acquisition software for the 300 kHz OCT system engine and an intuitive workflow- optimized user interface/user experience. Specific Aim 3: Validation Study. Use of the proposed HH-OCT system will be compared to current commercial HH-OCT systems in a validation study. The expected outcome of this proposal is the development and validation of a prototype high-speed, user-friendly HH-OCT system and software usable by ophthalmic and optometric technicians without the need for specialized training. We believe that the commercialization of this system will greatly improve the standard of eye care and general health care for infants, young children and patients unable to cooperate for eye imaging.