Posterior Segment Distortion in Ultra-Widefield Imaging Compared to Conventional Modalities

Abstract

Optos incorporates a consistent horizontal stretch to images. Combining images taken at right angles reduces the distortion. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:644-651.].

Ultra‐widefield fundus photography for radiation therapy planning of ocular tumours

“…Nicholson et al. () recently showed that UWF were distorted in the horizontal plane, but other authors found a nonuniformly distributed deformation of the images (Daftari et al. ; Muttuvelu & Kiilgaard ).…”

“…Three of these concerned montages of multiple SF images, and it is therefore impossible herein to distinguish whether this was due to the reconstruction or the UWF, but in the fourth case, all measurements were performed in the central SF, leaving the distortion solely explainable by the UWF. Nicholson et al (2016) recently showed that UWF were distorted in the horizontal plane, but other authors found a nonuniformly distributed deformation of the images (Daftari et al 2010;Muttuvelu & Kiilgaard 2019). More generally, distortions may be explained by the fact that fundus imaging is a projection of a curved surface on a plane surface, as seen on a world map.…”

Quantifying Retinal Area in Ultra-Widefield Imaging Using a 3-Dimensional Printed Eye Model

“…Numerous methods have been utilised to study image distortion in ultra-widefield imaging but this is the first reported study whereby 3-D printed model eyes have been used with the analysis of the influence of varying axial lengths on the image produced. [8][9][10] Previous reports have used known sizes such as the Argus implant or the optic disc but using a 3-D printed model eye, more detailed analyses can be performed. 9,10,16 From our study, we have identified several key findings.…”

“…[8][9][10] Previous reports have used known sizes such as the Argus implant or the optic disc but using a 3-D printed model eye, more detailed analyses can be performed. 9,10,16 From our study, we have identified several key findings. Firstly, despite software correction, there is still an increasing distortion towards the periphery.…”

“…4 Secondly, a horizontal stretch over the entire image that magnifies into the periphery has also been reported in uncorrected images. 8,9 Finally, the impact of different axial lengths on the images produced can vary the imaged size by almost 10%. 10 The ultra-widefield system is unique and still evolving, and it is important to rectify these flaws to realise the full potential of this system.…”