Abstract
Purpose :
Diagnosing and monitoring the progression of Retinopathy of Prematurity (ROP) is mainly performed using indirect ophthalmoscopy, and treatment is decided based on in situ exploration of the retinas of neonates, missing the benefit of objective assessment and long-term monitoring offered by recorded images. Diagnosing and assessing the severity of ROP requires visualizing the retinal periphery, however glare severely affects image quality if wide field-of-view (WFOV) is attempted, especially using a handheld and non-contact device. We propose an innovative technique for a handheld ophthalmoscope to provide images with sufficiently WFOV and quality to enable ROP diagnosis and monitoring.
Methods :
A handheld ophthalmoscope was designed and prototyped to acquire WFOV images of the retina, as shown in Figure 1. The system is based on a computational combination of multiple images that are recorded in rapid sequence. The acquisition is electronically synchronised with an illumination system designed to promote non-redundancy of information between images. This computational-imaging approach enables the reconstruction of a glare-suppressed and WFOV images of the retina. The illumination system is sourced by LED illumination and was designed to illuminate a WFOV area of the retina.
Results :
Images of retinas from volunteers were recorded and processed. Example results are shown in Figure 1 and demonstrate glare-free retinal imaging with a WFOV of 80°. Synchronization of illumination and image acquisition was electronically controlled and achieved the recording of the required multiple images in less than 200ms.
Conclusions :
A non-contact and handheld ophthalmoscope was designed and prototyped, capable of recording retinal views of up to 80°, enabling the assessment and monitoring the progression of ROP. Being non-contact and achieving WFOV provides a benefit over existing devices for ROP as corneal contact induces undesirable additional stress to premature infants. Multi-spectral information may also be extracted from the images, for example oximetry over tracked vessels may be possible. In particular, two-wavelength oximetry provides arterial/vein discrimination which benefits the diagnosis of Plus disease. The camera is sufficiently compact to operate within an incubator.
This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.