Additive Role of Optical Coherence Tomography Angiography Vessel Density Measurements in Glaucoma Diagnoses

Aim: To determine the minimum number of optical coherence tomography B-scan corrections required to provide acceptable vessel density measurements on optical coherence tomography angiography images in eyes with diabetic macular edema. Methods: In this prospective, noninterventional case series, the optical coherence tomography angiography images of eyes with center-involving diabetic macular edema were assessed. Optical coherence tomography angiography imaging was performed using RTVue Avanti spectral-domain optical coherence tomography system with the AngioVue software (V.2017.1.0.151; Optovue, Fremont, CA, USA). Segmentation error was recorded and manually corrected in the inner retinal layers in the central foveal, 100th and 200th optical coherence tomography B-scans. The segmentation error correction was then continued until all optical coherence tomography B-scans in whole en face image were corrected. At each step, the manual correction of each optical coherence tomography B-scan was propagated to whole image. The vessel density and retinal thickness were recorded at baseline and after each optical coherence tomography B-scan correction. Results: A total of 36 eyes of 26 patients were included. To achieve full segmentation error correction in whole en face image, an average of 1.72 ± 1.81 and 5.57 ± 3.87 B-scans was corrected in inner plexiform layer and outer plexiform layer, respectively. The change in the vessel density measurements after complete segmentation error correction was statistically significant after inner plexiform layer correction. However, no statistically significant change in vessel density was found after manual correction of the outer plexiform layer. The vessel density measurements were statistically significantly different after single central foveal B-scan correction of inner plexiform layer compared with the baseline measurements ( p = 0.03); however, it remained unchanged after further segmentation corrections of inner plexiform layer. Conclusion: Multiple optical coherence tomography B-scans should be manually corrected to address segmentation error in whole images of en face optical coherence tomography angiography in eyes with diabetic macular edema. Correction of central foveal B-scan provides the most significant change in vessel density measurements in eyes with diabetic macular edema.

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Repeatability of vessel density measurements of optical coherence tomography angiography in normal and glaucoma eyes

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2017-310637 ◽

2017 ◽

Vol 102 (3) ◽

pp. 352-357 ◽

Cited By ~ 55

Author(s):

Jayasree P Venugopal ◽

Harsha L Rao ◽

Robert N Weinreb ◽

Zia S Pradhan ◽

Srilakshmi Dasari ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Repeated Measures ◽

Optical Coherence Tomography Angiography ◽

Signal Strength ◽

Cross Sectional Study ◽

Vessel Density ◽

Optical Coherence ◽

Cross Sectional ◽

Density Measurements ◽

Density Values

AimsTo compare the intrasession repeatability of peripapillary and macular vessel density measurements of optical coherence tomography angiography (OCTA) in normal and glaucoma eyes, and to evaluate the effect of signal strength of OCTA scans on the repeatability.MethodsIn a cross-sectional study, three optic nerve head scans each of 65 eyes (30 normal, 35 glaucoma eyes) and three macular scans each of 69 eyes (35 normal, 34 glaucoma eyes) acquired in the same session with OCTA were analysed. Repeatability was assessed using within-subject coefficient of repeatability (CRw) and variation (CVw). Effect of signal strength index (SSI) on repeatability was evaluated with repeated-measures mixed-effects models.ResultsCRw (%) and CVw (%) of peripapillary measurements in normal eyes ranged between 3.3 and 7.0, and 2.5 and 4.4 respectively, and that in glaucoma eyes between 3.5 and 7.1, and 2.6 and 6.6. For the macular, these measurements ranged between 4.1 and 6.0, and 3.3 and 4.7 in normal eyes and 4.3 and 6.9, and 3.7 and 5.6 in glaucoma eyes. Repeatability estimates of most measurements were similar in normal and glaucoma eyes. Vessel densities of both peripapillary and macular regions significantly increased with increase in SSI of repeat scans (coefficients ranging from 0.15 to 0.38, p<0.01 for all associations).ConclusionsRepeatability estimates of OCTA measured peripapillary and macular vessel densities were similar in normal eyes and eyes with glaucoma. SSI values of the scans had a significant effect on the repeatability of OCTA with the vessel density values increasing in scans with higher SSI values.

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Anterior segment optical coherence tomography angiography for iris vasculature in pigmented eyes

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-316930 ◽

2020 ◽

pp. bjophthalmol-2020-316930

Author(s):

Marcus Ang ◽

Kavya Devarajan ◽

Anna CS Tan ◽

Mengyuan Ke ◽

Bingyao Tan ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Optical Coherence Tomography Angiography ◽

Anterior Segment ◽

Mean Difference ◽

Vessel Density ◽

Optical Coherence ◽

Swept Source ◽

Density Measurements ◽

Stage 1 ◽

Swept Source Octa

PurposeTo compare anterior segment optical coherence tomography angiography (AS-OCTA) systems in delineating normal iris vessels and iris neovascularisation (NVI) in eyes with pigmented irides.MethodsProspective study from January 2019 to June 2019 of 10 consecutive patients with normal pigmented iris, had AS-OCTA scans with a described illumination technique, before using the same protocol in five eyes with NVI (clinical stages 1–3). All scans were sequentially performed using a spectral-domain OCTA (SD-OCTA), and a swept-source OCTA (SS-OCTA, Plex Elite 9000). Images were graded by two masked observers for visibility, artefacts and NVI characteristics. The main outcome measure was iris vessel density measurements comparing SS-OCTA and SD-OCTA systems.ResultsThe median age of subjects was 28 (20–35) years, and 50% were female. The paired mean difference of iris vessel density measurements was 11.7 (95% CI 14.7 to 8.1; p=0.002), SS-OCTA detecting more vessels than SD-OCTA. The inter-rater reliability for artefact score (κ=0.799, p<0.001) and visibility score (κ=0.722; p<0.001) were substantial. Both AS-OCTA systems were able to detect NVI vessels with a fair agreement (κ=0.588), with clearer NVI characteristics in stage 1/2 compared to stage 3 NVI (mean difference NVI score: 2.7±0.4, p=0.009).ConclusionThe SS-OCTA was better able to delineate iris vessels in normal pigmented irides compared to SD-OCTA. Both AS-OCTA systems identified NVI characteristics based on its atypical configuration or location, but further improvements are needed to allow for more accurate objective, serial quantification for clinical use.

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Repeatability of ocular surface vessel density measurements with optical coherence tomography angiography

10.21203/rs.1.24/v1 ◽

2018 ◽

Keyword(s):

Optical Coherence Tomography ◽

Ocular Surface ◽

Optical Coherence Tomography Angiography ◽

Vessel Density ◽

Optical Coherence ◽

Density Measurements ◽

Surface Vessel

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Role of anterior segment optical coherence tomography angiography in assessing limbal vasculature in acute chemical injury of the eye

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2021-318847 ◽

2021 ◽

pp. bjophthalmol-2021-318847

Author(s):

Marcus Ang ◽

Valencia Foo ◽

Mengyuan Ke ◽

Bingyao Tan ◽

Louis Tong ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Optical Coherence Tomography Angiography ◽

Rapid Assessment ◽

Anterior Segment ◽

Vessel Density ◽

Optical Coherence ◽

Slit Lamp ◽

Swept Source ◽

Chemical Injury

PurposeTo study the role of two anterior segment optical coherence tomography angiography (AS-OCTA) systems in eyes with acute chemical injury.MethodsProspective study in subjects with unilateral chemical injuries. Sequential slit-lamp assessment with spectral domain (SD) (AngioVue, Optovue, USA) and swept source (SS) (Plex Elite, Zeiss, Carl Zeiss Meditec, Dublin, California, USA) AS-OCTA was performed in both eyes within 24–48 hours of injury. Subjects were managed with a standard clinical protocol and followed-up for 3 months. We assessed limbal disruption (loss of normal limbal vessel architecture), limbal vessel density measurements and agreement (kappa coefficient, κ) between masked assessors of limbal disruption based on AS-OCTA scans and slit-lamp assessment.ResultsTen subjects with median age 31 (25–33) years, 20% women, 60% suffered alkali injuries (Roper-Hall grade 1.5±0.7, Dua grade 2.3±1.2) at presentation. Mean limbal vessel density was lower in quadrants of affected eyes compared with controls detected by SD AS-OCTA (9.4%±2.0% vs 15.5%±1.8%, p<0.001) and SS AS-OCTA (8.8%±2.5% vs 13.9%±1.3%, p=0.01). There was substantial agreement when assessing limbal disruption on AS-OCTA (κ=0.7) compared with slit-lamp evaluation (κ=0.4). Overall, we found good agreement between SD and SS AS-OCTA systems in assessing limbal vessel density in eyes with chemical injury at presentation (mean paired difference: −1.08, 95% CI −3.2 to 0.5; p=0.189).ConclusionsIn this pilot study, AS-OCTA provided objective, non-contact, rapid assessment of limbal vasculature involvement in eyes with acute chemical injury. Further studies are required to establish the role of AS-OCTA in determining the prognosis of eyes with chemical injury.

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