ABSTRACT
BACKGROUND AND OBJECTIVE: Choroidal vascularity index (CVI) is a noninvasive tool to assess choroidal structure. The objective of the current study was to compare the CVI measurements on swept-source optical coherence tomography (SS-OCT) and spectral-domain OCT (SD-OCT) scans using the same image binarization protocol. PATIENTS AND METHODS: This prospective study was conducted from July 2016 through January 2017 and involved 54 healthy volunteers at a tertiary referral eye care institute in Southern India. Choroidal scans were obtained using both SS- and SD-OCT machines. An automated binarization algorithm was used to compute CVI. RESULTS: The mean CVI with SS-OCT scans was 53.88% ± 12.54% (range: 20.46% to 73.93%), whereas the mean CVI with SD-OCT scans was 51.11% ± 7.97% (range: 29.90% to 67.72%)(P < .001). The unadjusted (95% confidence interval [CI], 0.554-0.851) and adjusted (95% CI, 0.607-0.871) intraclass correlation (ICC) estimates were quite similar and indicate moderate-to-good reliability of measurements by two machines. The interval estimate for a conversion factor between SD-OCT and SS-OCT can be calculated as follows: SD = [0.383*SS+19.467, 0.586*SS+30.661]. CONCLUSION: CVI is a noninvasive, robust, and reliable measurement of choroidal vascularity and CVI measurements obtained using both SS-OCT and SD-OCT concur with each other. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e26-e32.].
Subject(s)
Choroid/blood supply , Tomography, Optical Coherence/methods , Adult , Aged , Algorithms , Choroid/diagnostic imaging , Female , Healthy Volunteers , Humans , Image Processing, Computer-Assisted/methods , Male , Middle Aged , Prospective Studies , Reproducibility of Results , Young AdultABSTRACT
Purpose: To correlate changes in choroidal thickness and vascularity index with disease activity in patients with neovascular age-related macular degeneration (nAMD). Methods: Eyes diagnosed with AMD that had two sequential visits within 12 months and that had no choroidal neovascularization (CNV) or had inactive CNV at the first visit were included. Those that had active CNV at follow-up were enrolled as cases. Eyes that did not developed a CNV or that were still inactive at the second visit were enrolled as controls. Disease activity was based on optical coherence tomography (OCT) and fluorescein angiography findings. Subfoveal choroidal thickness (SCT), mean choroidal thickness (MCT), and choroidal vascularity index (CVI) were assessed on enhanced depth imaging OCT and compared between the baseline and follow-up visit. Subgroup analysis accounting for lesion type and previous treatment, if any, were performed. Results: Sixty-five eyes from 60 patients (35 females) and 50 age- and sex-matched controls were included. At the active visit, cases had an increase from 164 ± 67 µm to 175 ± 70 µm in mean ± SD SCT and from 144 ± 45 µm to 152 ± 45 µm in MCT (both P < 0.0001). The mean CVI also increased at from 54.5% ± 3.3% to 55.4% ± 3.8% (P = 0.04). Controls did not show significant changes in choroidal measurements between the two visits. Mean SCT, MCT, and CVI values were similar for previously treated and treatment-naive eyes. Conclusions: Choroidal thickness and CVI significantly increased with active disease in nAMD eyes. Changes in choroidal thickness may predict CNV development or recurrence before they are otherwise evident clinically.
