Comparisons of Effective Fields of Two Ultra-Widefield Ophthalmoscopes, Optos 200Tx and Clarus 500

Abstract

Purpose To compare the effective fields of the Optos 200Tx® and Clarus 500™, two ultra-widefield ophthalmoscopes, based on their ability to image branches of retinal vessel in the four retinal quadrants. Methods Ninety retinal images from 90 patients with various eye diseases were studied. All patients had undergone 200° retinal imaging to obtain a single image of Optos (O) and the montage of two images of the Clarus (C). The highest number of traceable vessel branches in the four retinal quadrants was determined by two masked raters. An image was classified as “O > C” when the number of identifiable branch was greater in the Optos than the Clarus, as “O = C” when the number was equal and as “O < C” when the number was fewer in the Optos than the Clarus. Results The appearance probability of “O > C” was significantly higher at the upper temporal quadrant than “O < C” (p < 0.01 for both raters). In contrast, the appearance probability of “O < C” was significantly higher at the lower nasal quadrant than “O > C” (p < 0.01 for both raters). There were no significant differences in the appearance probability between “O > C” and “O < C” at the other two retinal quadrants (p > 0.50 for both raters). Conclusions These results demonstrate that the effective field of views was different between the two devices at different retina quadrants. Further studies are needed to clarify possible factors such as artifacts by the eyelashes, differences in the depth of focus, motion of the device, and different locations of the images on the effective field of views.

Artificial intelligence for improving sickle cell retinopathy diagnosis and management

“…Relative advantages of the Clarus compared to Optos are true-colour imaging and reduced eyelid or eyelash artefact, but relative disadvantages of the Clarus are a brighter light flash and a smaller field of capture of 133°from individual imagesalthough montaging increases the overall field of view [27]. One study reported that Optos images tend to capture retinal vascular detail in the superotemporal quadrant better than montaged Clarus images, which in turn may better capture retinal vascular detail in the inferonasal quadrant [32]. The implications of these findings for imaging of SCR (which preferentially affects the temporal retina) merit further study.…”

Comparison of Two Ultra-Widefield Cameras With High Image Resolution and Wider View for Identifying Diabetic Retinopathy Lesions

“…When looking at lesions detected in zone C3, more lesions were detected by the Optos P200dTx, as it captures a wider field of view in a single image. 19 The lesser sensitivity of the Zeiss Clarus 500 in the temporal quadrant in this study is likely due to a lesser field of view for single images acquired in the temporal quadrant.…”

“…These findings could be due to the Optos P200dTx utilizing pseudocolor imaging with a resolution of 14 to 20 µm when compared with the Zeiss Clarus 500, which utilizes true color imaging with a resolution of 7 µm. 19 Additionally, the issues with identification of lesions anterior to the retina, such as vitreous hemorrhage, could be due to the technique of imaging, as the photographer aims to focus on the posterior pole, as well as by the fact that the Optos P200dTx captures the image as soon as the posterior pole is clearly imaged on the sensor.…”

Comparison of two ultra-widefield color-fundus imaging devices for visualization of retinal periphery and microvascular lesions in patients with early diabetic retinopathy

“…Chen et al described an advantage of the Optos in all quadrants compared to the Clarus with the largest additional area depicted in the temporal quadrant 15 . Matsui et al compared retinal vessel branches to determine the effective fields seen on both devices and found more retinal vessels in the superotemporal quadrant on the Optos 200Tx, compared to more in the inferonasal quadrant on the Clarus 500 25 . Using anatomical landmarks to compare images, we could also detect an advantage of the Optos in our temporal peripheral field F3.…”