Comparison of Widefield and Circumpapillary Circle Scans for Detecting Glaucomatous Neuroretinal Thinning on Optical Coherence Tomography

Abstract

PurposeOur purpose was to compare the effectiveness of detecting progressive retinal nerve fiber layer (RNFL) thickness changes using widefield scans compared to circumpapillary circle scans derived from optic disc volume scans when using a manual region-of-interest (ROI) approach.MethodsIn a prospective observational study, a total of 125 eyes diagnosed clinically with glaucoma or suspected glaucoma that had both widefield (12 × 9 mm) and optic disc (6 × 6 mm) scans obtained at least one year apart were included. Changes in the RNFL thickness between the two visits were evaluated within region(s) of observed or suspected glaucomatous damage, which were manually outlined after reviewing key features from each scan on the second visit (described as a manual ROI approach). Within ROI(s), changes in the widefield and circumpapillary RNFL thickness (wfRNFLROI and cpRNFLROI), as well as in the global circumpapillary RNFL thickness (cpRNFLG), were determined. The performance of these three methods for detecting progressive changes was compared using longitudinal signal-to-noise ratios (SNRs), whereby the rate of change determined by each method was normalized by individualized estimates of measurement variability and age-related change.ResultsOn average, the longitudinal SNRs for the wfRNFLROI, cpRNFLROI, and cpRNFLG methods were −0.57, −0.38, and −0.23 y−1, respectively, being significantly more negative for the wfRNFLROI than the latter two methods (P ≤ 0.009).ConclusionsProgressive RNFL thickness changes were more effectively detected on widefield optical coherence tomography (OCT) scans using a manual ROI approach compared to conventional derived circumpapillary circle scans.Translational RelevanceWidefield OCT scans show promise for improving the detection of glaucomatous progression.

Intra‐session repeatability of quantitative metrics using widefield optical coherence tomography angiography (OCTA) in elderly subjects

“…In patients with glaucoma, studies have shown that reduced macular (Yarmohammadi et al 2017), circumpapillary (Lommatzsch et al 2018) and whole-image VD of 4.5 9 4.5-mm 2 scans on OCTA (Yarmohammadi et al 2016) are significantly associated with disease severity. As a relatively new scan protocol, widefield 12 9 12mm 2 scans are especially valuable in glaucoma diagnostics and management as encompass the macular and circumpapillary vasculature in one single image (Wu et al 2018). Despite the lack of existing literature discussing the repeatability of 12 9 12-mm 2 scans, our results support the longitudinal use of 12 9 12-mm 2 scans in managing patients with diabetic retinopathy and glaucoma.…”

“…As a relatively new scan protocol, widefield 12 × 12‐mm 2 scans are especially valuable in glaucoma diagnostics and management as encompass the macular and circumpapillary vasculature in one single image (Wu et al. ). Despite the lack of existing literature discussing the repeatability of 12 × 12‐mm 2 scans, our results support the longitudinal use of 12 × 12‐mm 2 scans in managing patients with diabetic retinopathy and glaucoma.…”

Comparison of a commercial spectral-domain OCT and swept-source OCT based on an angiography scan for measuring circumpapillary retinal nerve fibre layer thickness

“…Conventionally, the RNFL thickness using SD-OCT is evaluated from a single circle around the optic disc, but wide-field scan could be more effective in determining the RNFL thickness progression. 34 In addition, wide-field scanning enables the ganglion cell analysis from the fovea together with RNFL measurements to better understand the relation between the loss of macular ganglion cells and their axons. 35 …”

Sample Size Requirements of Glaucoma Clinical Trials When Using Combined Optical Coherence Tomography and Visual Field Endpoints

“…It should be noted that the value of OCT imaging for reducing the sample size requirements in this study was achieved by using the standard global circumpapillary RNFL thickness measure. However, recent studies have revealed how neuroretinal parameters in the macula and posterior pole (outside of the peripapillary region) could also provide important information about disease progression 10–14,22,23 that could be exploited to further improve the power to detect a significant treatment effect. Furthermore, analytical methods that limit the evaluation of progression within regions of established glaucomatous damage (to minimize the contribution of measurement variability from non-damaged regions) could further reduce sample size requirements 23–26 .…”