Yifan Jian

This study reports a non-contact, multimodal visible-light OCT (vis-OCT) and scanning laser ophthalmoscopy (SLO) system for in vivo mouse retinal imaging that achieves a single-shot 100° (visual angle) field of view (FOV). By performing repeated B-scans at the same location, the system enables OCT angiography (OCTA). With a long working distance (6.4 mm), the system also allows ready realignment without disrupting native ocular optics or physiology. We validated system performance in transgenic mice expressing fluorescently labeled microglia, including both healthy mice and oxygen-induced retinopathy (OIR) models. Images from the device clearly resolve individual nerve fiber bundles, inter-plexus capillaries, and individual microglia. Hyaloid vessel shadows and tortuous vessels in OIR mice are also discernible. Together, these capabilities provide a platform for the comprehensive assessment of vascular dysfunction and microglia behavior, offering a promising tool for investigating retinal diseases that affect the peripheral regions.

Purpose: To characterize early morphologic changes of the ridge and isolated retinal neovascularization (IRNV) after intravitreal bevacizumab (IVB) treatment for ROP using investigational ultra-widefield OCT (UWF-OCT). Methods: UWF-OCT were acquired weekly from the date of treatment through at least four weeks post treatment. Results: A total of 44 eyes from 23 infants were imaged. By one-week post-treatment, UWF-OCT demonstrated marked regression of neovascular tufts and flattening of the fibrovascular ridge. The ridge progressed anteriorly, but neovascularization did not change location throughout its course of regression. Through week four, residual ridge tissue exhibited segmental thinning and remodeling. Conclusion: IVB for ROP induces rapid regression of IRNV and ridge thickness in the initial weeks post-treatment with subsequent remodeling over the first month. UWF-OCT enables detailed characterization of these dynamic morphologic changes, providing potential biomarkers for monitoring treatment responses and identifying eyes at risk of reactivation.

Ultra-widefield retinal imaging is critical for diagnosing peripheral retinal diseases, but discrepancies in field of view (FOV) definitions hinder system comparisons. This study aims to evaluate the FOV performance of six widefield or ultra-widefield retinal imaging systems using a simplified eye phantom model and in vivo demonstration in a healthy subject. A custom eye phantom model with concentric ring patterns and geometric markers was used to assess FOV and distortion across six imaging systems, including Nikon Optos, Natus RetCam, Intalight Dream OCT, Siloam Vision's contact and non-contact iCam-OCT, and OHSU table-top UWF OCT. The phantom model eliminated anatomic variability, enabling controlled measurements. Imaging was also performed on a healthy emmetropic adult under identical conditions for qualitative validation. The evaluation revealed significant variations in peripheral coverage and distortion among systems. Nikon Optos and Siloam Vision contact iCam-OCT achieved the widest FOVs, whereas RetCam and Intalight Dream OCT had more limited coverage. Radial and tangential distortion increased with eccentricity, with Nikon Optos exhibiting the highest distortion. In vivo imaging confirmed phantom-based findings regarding FOV coverage and distortion across these systems. FOV performance varies across imaging systems, and the measured FOVs were generally consistent with the manufacturers stated specifications. Distortion increased with eccentricity and differed among devices. The phantom model provided an objective method for quantifying FOV and distortion, with findings supported by in vivo imaging. This work offers a practical method for evaluating widefield imaging systems, supporting informed system selection, and emphasizing consistent evaluation criteria in clinical practice.

The mouse retina serves as a critical model for studying human eye diseases. Optical coherence tomography (OCT) has rapidly advanced as a technique for retinal imaging, with OCT Angiography (OCTA) and Optoretinogram (ORG) emerging as significant functional extensions. High-speed, multifunctional imaging systems markedly enhance the efficiency of experiments by enabling fast and comprehensive data collection from the living mouse retina. However, integrating both high-speed operations and multiple functionalities poses challenges in data acquisition, real-time processing, post-processing, and system complexity. To address these challenges, we developed a high-speed imaging system leveraging a high-speed swept laser source, and a high-speed digitizer for data acquisition. The data acquisition software, developed with C++ and CUDA (Compute Unified Device Architecture), is optimized for rapid and efficient data capture and processing. We reduced system complexity by integrating OCT, OCTA, and ORG protocols and reprogramming post-processing software. Our system, operating at a 400 kHz A-scan rate, supports both structural and functional imaging with a 5.0 μm axial resolution and consistent sensitivity of 53 dB across a 2 mm depth. Utilizing the temporal speckle averaging (TSA) technique, we achieved high contrast-to-noise ratio images, allowing us to delineate retinal structures and blood vessels. For ORG analysis, we developed intensity-based and phase-based methods to evaluate the retina’s light-evoked responses. The intensity-based approach effectively detects photoreceptor elongation and scattering changes, while the phase-based method provides a highly sensitive detection with a temporal resolution of up to 1 ms, revealing subtle changes in the length of the outer segment junction. Overall, this system, to our knowledge, offers the most comprehensive and high-speed imaging capabilities available, delivering detailed structural and functional insights into the living mouse retina.

Panretinal optical coherence tomography (PanOCT) enables rapid, widefield retinal imaging up to 140°, visualizing peripheral regions including the ora serrata. However, raw B-scan images exhibit curvature distortion, limiting quantitative accuracy. We present a curve correction method to restore geometric fidelity. Validation with a custom 3D-printed eye phantom showed average relative errors under 1%. Clinical comparisons with CT and ultrasound demonstrated errors of 2.78% and 5.97%, respectively. These results indicate strong agreement with standard imaging modalities and support the utility of PanOCT for accurate widefield retinal measurements in clinical and research applications.

We present a handheld, non-mydriatic optical coherence tomography (OCT) system engineered for panretinal imaging across both pediatric and adult patients. The prototype achieves a 140° visual angle, enabling detailed visualization from the posterior pole to the peripheral retina without the need for pharmacologic dilation or scleral depression. A customized optical design minimizes beam wander while maintaining diffraction-limited resolution throughout the field of view. The system employs a 400 kHz VCSEL light source, facilitating high-speed image acquisition along with an extended axial imaging range of 12 mm in air, sufficient to accommodate retinal curvature. This combination of optical and hardware enhancements allows for rapid and comprehensive retinal assessment in a variety of clinical environments. To date, the system has been used in 117 imaging sessions involving broad patient cohorts, including 32 premature infants in a neonatal intensive care unit, as well as pediatric and adult patients in outpatient settings. In these sessions, the system has consistently produced high-resolution en face OCT images, B-scans, and OCT angiography (OCTA), demonstrating strong potential for diagnosing and monitoring peripheral retinal pathologies. The handheld, non-mydriatic design supports flexible use at the bedside and in preoperative settings, offering particular advantages in pediatric ophthalmology where conventional imaging techniques may be impractical.

Background: Optical coherence tomography (OCT) is a leading ocular imaging modality, known for delivering high-resolution volumetric morphological images. However, conventional OCT systems are limited by their narrow field-of-view (FOV) and their reliance on scattering contrast, lacking molecular specificity. Methods: To address these limitations, we developed a custom-built 105^∘ ultra-widefield polarization-diversity OCT (UWF PD-OCT) system for assessing various retinal and choroidal conditions, which is particularly advantageous for visualizing peripheral retinal abnormalities. Patients with peripheral lesions or pigmentary changes were imaged using the UWF PD-OCT to evaluate the system’s diagnostic capabilities. Comparisons were made with conventional swept-source OCT and other standard clinical imaging modalities to highlight the benefits of depolarization contrast for identifying pathological changes. Results: The molecular-specific contrast offered by UWF PD-OCT enhanced the detection of disease-specific features, particularly in the peripheral retina, by capturing melanin distribution and pigmentary changes in a single shot. This detailed visualization allows clinicians to monitor disease progression with greater precision, offering more accurate insights into retinal and choroidal pathologies. Conclusions: Integrating UWF PD-OCT into clinical practice represents a major advancement in ocular imaging, enabling comprehensive views of retinal pathologies that are difficult to capture with current modalities. This technology holds great potential to transform the diagnosis and management of retinal and choroidal diseases by providing unique insights into peripheral retinal abnormalities and melanin-specific changes, critical for early detection and timely intervention.