Comparative Evaluation of Field of View Across Widefield Retinal Imaging Systems

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.