Influence of ocular biometry on peripheral retinal visualization: A comparative study of Clarus and Optos widefield imaging systems

Background The purpose was to compare the Clarus 500 and Optos Daytona widefield imaging systems with respect to the farthest clinically assessable peripheral retinal structure in each quadrant, and to evaluate whether ocular biometry, particularly axial length and spherical equivalent, influences device specific widefield performance. Methods Twenty-six eyes underwent same day widefield imaging with Clarus 500 (Zeiss Meditec AG, Jena, Germany) and Optos Daytona (Optos plc, Dunfermline, UK). For each quadrant, the most peripheral anatomically interpretable structure was identified, and device differences were analyzed using McNemar tests. Associations with axial length and spherical equivalent, were evaluated using Mann-Whitney U tests and univariate and multivariate logistic regression. Receiver operating characteristic analysis was performed to assess the predictive value of axial length and to determine the optimal cutoff for device superiority. Results Both widefield systems showed similar performance in the superior temporal, inferior temporal, and inferior nasal quadrants with no statistically significant differences. In the superior nasal quadrant, however, eyes in which Clarus reached farther had significantly longer axial length (23.97 ± 1.62 mm versus 22.53 ± 0.94 mm, p = 0.016) and a more myopic spherical equivalent (− 2.05 ± 4.52 D versus + 2.69 ± 2.56 D, p = 0.019). Axial length significantly predicted Clarus superiority in univariate regression (odds ratio 2.39, p = 0.033). Receiver operating characteristic analysis demonstrated good discriminatory ability of axial length with an area under the curve of 0.782 and an optimal cutoff of 23.77 mm. Shorter and hyperopic eyes showed a tendency toward greater peripheral reach with Optos, although this trend did not achieve statistical significance. Conclusion The Clarus 500 and Optos Daytona provide comparable peripheral visualization in most retinal quadrants. Device differences become apparent in the superior nasal quadrant, where axial elongation and myopic ocular geometry enhance Clarus performance, while no statistically supported advantage for Optos is observed in shorter or hyperopic eyes. These findings underscore the relevance of ocular biometry in widefield retinal imaging and support individualized device selection in patients with myopic anatomy. Overall, both devices demonstrated robust and reliable performance, providing high quality widefield imaging suitable for comprehensive peripheral retinal assessment.