ABSTRACT
BACKGROUND: To evaluate the reliability of foveal avascular zone (FAZ) area measurements using optical coherence tomography angiography (OCTA) in eyes with retinal vein occlusion (RVO). METHODS: Twenty-five OCTA exams of patients with RVO were evaluated retrospectively. Three examiners performed manual measurements of the FAZ, and interrater and intrarater reliability were obtained. RESULTS: The intraclass correlation coefficient (ICC) for interrater reliability for individual measurements was 0.62 (moderate) with a 95% confidence interval (CI) of 0.40 to 0.79 (p < 0.001). The ICC (95% CI) for intrarater reliability was 0.92 (0.82 to 0.96) for rater A, 0.96 (0.91 to 0.98) for B, and 0.88 (0.76 to 0.94) for C (p < 0.001). In all subanalyses including presence of edema and type of occlusion, interrater reliability was poor/moderate, and intrarater reliability was good/excellent. CONCLUSION: The FAZ varies significantly among eyes with RVO, so measurements obtained using OCTA should be analyzed with caution due to the moderate level of reliability among different examiners.
ABSTRACT
OBJECTIVE: To study the automated segmentation of retinal layers using spectral domain optical coherence tomography (OCT) and the impact of manual correction over segmentation mistakes. METHODS: This was a retrospective, cross-sectional, comparative study that compared the automated segmentation of macular thickness using Spectralis™ OCT technology (Heidelberg Engineering, Heidelberg, Germany) versus manual segmentation in eyes with no macular changes, macular cystoid edema (CME), and choroidal neovascularization (CNV). Automated segmentation of macular thickness was manually corrected by two independent examiners and reanalyzed by them together in case of disagreement. RESULTS: In total, 306 eyes of 254 consecutive patients were evaluated. No statistically significant differences were noted between automated and manual macular thickness measurements in patients with normal maculas, while a statistically significant difference was found in central thickness in patients with CNV and with CME. Segmentation mistakes in macular OCTs were present in 5.3% (5 of 95) in the normal macula group, 16.4% (23 of 140) in the CME group, and 66.2% (47 of 71) in CNV group. The difference between automated and manual macular thickness was higher than 10% in 1.4% (2 of 140) in the CME group and in 28.17% (20 of 71) in the CNV group. Only one case in the normal group had a higher than 10% segmentation error (1 of 95). CONCLUSION: The evaluation of automated segmented OCT images revealed appropriate delimitation of macular thickness in patients with no macular changes or with CME, since the frequency and magnitude of the segmentation mistakes had low impact over clinical evaluation of the images. Conversely, automated macular thickness segmentation in patients with CNV showed a high frequency and magnitude of mistakes, with potential impact on clinical analysis.
ABSTRACT
BACKGROUND: Functional and anatomical evaluation of patients with ischemic diabetic macular edema after monthly injections of Bevacizumab. METHODS: Five eyes from five patients with diabetic macular edema associated with macular ischemia in fluorescein angiography (FA), received 6 monthly intravitreal injections of Bevacizumab. All subjects underwent SD-OCT, FA, OCT angiography (OCTA) and microperimetry at baseline and after 6 months follow-up. Primary outcome measures were improvement of best corrected visual acuity (BCVA), microperimetry and assessment of macular perfusion (foveal avascular zone size and capillary loss). RESULTS: Five patients completed the follow-up. BCVA improved from 20/180 to 20/74 (p = 0.01) and macular sensitivity improved from 11.66 to 16.26 dB (p < 0.007). We also observed that areas of ischemia on OCTA represented areas of lower macular sensitivity on microperimetry. No changes in macular perfusion status were noted. CONCLUSIONS: Monthly intravitreal Bevacizumab in patients with ischemic diabetic macular edema improved BCVA and macular sensitivity without compromise of perfusion in the macula. Capillary dropout areas in OCTA correlated with lower retinal sensitivity on microperimetry.
