A Comparison of Ultra-Widefield Imaging Quality Obtained with Zeiss Clarus and Optos for Virtual Medical Retina Services

Abstract

Background: Virtual clinics (VCs) have proven to be an effective solution for the increasing strain on Medical Retina (MR) services, although imaging quality issues (IQIs) persist. Our aim was to compare the quality of two ultra-wide-field (UWF) imaging modalities (Optos and Clarus) in real-world MR-VC settings. Methods: We conducted a real-world, prospective study. Data were collected from 6 Moorfields NHS Trust MR-VCs between September and October 2024. We obtained patient demographics and characteristics, primary diagnosis, UWF imaging types and images obtained, and follow-up outcomes. Results: Optos (California RG/RGB, and Monaco) was used for 56.7% (n = 152) and Zeiss Clarus 500 for 43.3% (n = 116) of the total cohort (n = 268). No statistically significant difference (p = 0.14) was found between the two in terms of the rates of IQIs. FAF (p = 0.001) acquisition was significantly higher when Optos was used. Of the patients affected by IQIs, 10 were examined in a face-to-face clinic (F2FC). No difference in IQI rates was observed when pathology-related poor image quality was considered (p = 0.561). A significantly (p = 0.001) higher rate of F2F follow-ups was found for red-flag pathologies and unexplained vision loss, with a statistically significantly higher rate of virtual follow-ups for non-red-flag pathologies (p = 0.001). Conclusions: A total of 7.5% of the clinical decisions were impacted by IQIs; 11.1% of F2FC follow-ups. Neither UWF imaging modality type was inferior in terms of IQI rates. FAF acquisition was higher with Optos, likely representing greater user-dependency for Clarus. The outcomes were not influenced by FAF acquisition, indicating that routine acquisition is not required in MR-VCs and instead should be obtained when clinically required.

Keywords: Optos; Zeiss Clarus; medical retina virtual clinic; ultrawide-field imaging.

Figure 1

Moorfields Medical Retina virtual clinic pathway (at the time this study was conducted).

Figure 2

Example images from study patients: (a) insufficient field of view obtained using Clarus; (b) insufficient field of view obtained using Optos; (c) artefact in Clarus imaging; (d) artefact in Optos imaging; and (e) poor image quality obtained using Optos.

Figure 3

Primary reasons for follow-up stratified into imaging-related and non-imaging-related reasons, with a comparison of the Optos and Clarus sub-groups [n = 266; missing data = 2].

Figure 4

Further stratification of the primary reasons for follow-ups, with a comparison of the Optos and Clarus sub-groups: (a) imaging-quality-related primary reasons for follow-ups [n = 20], and (b) non-imaging-quality-related primary reasons for follow-ups (related to clinical need) [n = 244; missing data = 2].

Figure 5

Follow-up data: (a) follow-up setting [n = 257; missing data = 11] and (b) follow-up period [n = 262; missing data = 6].