Standardizing Ocular Surface Photography Using A Novel Imaging System

The aim of this study was to demonstrate safety, feasibility and clinical performance of a novel imaging system for standardized, high-resolution external eye photography, compared to state of the ocular surface art slit-lamp photography.. The system is equipped with a custom-made lens with a curved focal surface adapted to the external ocular curvature. An integrated fixation target, automated iris tracker, single illumination setting and auto-focus mode allow simple and standardized imaging of the entire visible ocular surface in focus with a single shot. Further aims were to highlight the importance of imaging standardization for high throughput ocular surface photography to improve clinical management of ocular surface disease (OSD). 

Prospective comparative clinical study involving patients visiting an outpatient clinic of an academic tertiary care referral center for Ophthalmology. 

An ophthalmic photography system prototype (Occyo GmbH, Innsbruck, A) was used to capture ocular surface images from patients with various types of OSD. The prototype's performance was evaluated and compared to state of the art slit-lamp photography using the IM-900 imaging module (Haag Streit, Köniz, CH). A series of 3 images was recorded in mesopic and photopic room light conditions for all cases with both systems. Outcome parameters included  feasibility duration of an imaging session, per and post imaging, visual contrast sensitivity, and image quality parameters (focus, color, hue, lightness).

Interim analysis of 83 of a total 100 cases was performed. Imaged ocular surface pathologies included penetrating corneal grafts, pterygium, pingueculum, corneal foreign bodies, epithelial defects, superficial punctate and microbial keratitis. The system was capable of capturing high-resolution images of the entire visible ocular surface with minimized gaze-dependent image decentration and lightness variability compared to slit-lamp photography. Safety and feasibility was confirmed. Peripheral image defocus over the conjunctival vasculature was reduced compared to slit-lamp photography, enabling superior delineation of conjunctival vasculature.

The tested external eye photography system is able to capture high quality images to document clinical features of OSD, applicable to clinical and research purposes, thus standardizing the process. Simplicity of use and speed of image acquisition make it feasible for high-throughput clinical workflows.