Vascular changes of the choroid and their correlations with visual acuity in diabetic retinopathy.

Objective: To investigate changes in the choroidal vasculature and their correlations with visual acuity in diabetic retinopathy (DR). Methods: The cohort was composed of 225 eyes from 225 subjects, including 60 eyes from 60 subjects with healthy control, 55 eyes from 55 subjects without DR, 46 eyes from 46 subjects with nonproliferative diabetic retinopathy (NPDR), 21 eyes from 21 subjects with proliferative diabetic retinopathy (PDR), and 43 eyes from 43 subjects with clinically significant macular edema (CSME). Swept-source optical coherence tomography (SS-OCT) was used to image the eyes with a 12-mm radial line scan protocol. The parameters for 6-mm diameters of region centered on the macular fovea were analyzed. Initially, a custom deep learning algorithm based on a modified residual U-Net architecture was utilized for choroidal boundary segmentation. Subsequently, the SS-OCT image was binarized and the Niblack-based automatic local threshold algorithm was employed to calibrate subfoveal choroidal thickness (SFCT), luminal area (LA), and stromal area (SA) by determining the distance between the two boundaries. Finally, the ratio of LA and total choroidal area (SA + LA) was defined as the choroidal vascularity index (CVI). The choroidal parameters in five groups were compared, and correlations of the choroidal parameters with age, gender, duration of diabetes mellitus (DM), glycated hemoglobin (HbA1c), fasting blood sugar, SFCT and best-corrected visual acuity (BCVA) were analyzed. Results: The CVI, SFCT, LA, and SA values of patients with DR were found to be significantly lower compared to both healthy patients and patients without DR (P < 0.05). The SFCT was significantly higher in NPDR group compared to the No DR group (P < 0.001). Additionally, the SFCT was lower in the PDR group compared to the NPDR group (P = 0.014). Furthermore, there was a gradual decrease in CVI with progression of diabetic retinopathy, reaching its lowest value in the PDR group. However, the CVI of the CSME group exhibited a marginally closer proximity to that of the NPDR group. The multivariate regression analysis revealed a positive correlation between CVI and the duration of DM as well as LA (P < 0.05). The results of both univariate and multivariate regression analyses demonstrated a significant positive correlation between CVI and BCVA (P = 0.003). Conclusion: Choroidal vascular alterations, especially decreased CVI, occurred in patients with DR. The CVI decreased with duration of DM and was correlated with visual impairment, indicating that the CVI might be a reliable imaging biomarker to monitor the progression of DR.

Evaluation of macular neovascularization activity in pathological myopia: a comparison between optical coherence tomography and OCT-angiography.

Purpose: The purpose of this study was to suggest a novel approach to assessing the activity of macular neovascularization (MNV) in pathological myopia (PM) by comparing optical coherence tomography (OCT) with OCT-angiography (OCT-A). Methods: The Zeiss Cirrus HD-5000 was used to obtain OCT and OCT-A images of PM-MNV. The objective was to examine the characteristics of PM-MNV lesions and investigate the relationship between PM-MNV activity and changes in retinal structure in 54 patients (54 eyes). To analyze the OCT parameters associated with PM-MNV activity and their clinical significance in terms of sensitivity and specificity, we used OCT-A as a reference. Results: This study included 72 patients (72 eyes), of whom 54 had good image quality and were considered for analysis. The study evaluated various OCT characteristics of MNV lesions, including the elevation of an external limiting membrane (ELM), ellipsoidal zone (EZ), retinal pigment epithelium (RPE) elevation, and EZ/RPE interruption, to identify possible parameters associated with PM-MNV activity. The interobserver consistency was found to be almost perfect. In the evaluation of PM-MNV activity, the sensitivity of ELM elevation, EZ interruption, and RPE interruption was found to be 66.7% (low), 88.4% (high), and 95.6% (high), respectively. However, the specificity was found to be 71.4% (moderate), 71.4% (moderate), and 25.4% (poor), respectively. This indicates that the current evaluation methods are not accurately assessing PM-MNV activity. We developed a new comprehensive method that used EZ interruption as the primary parameter and ELM elevation and RPE interruption as secondary parameters to evaluate PM-MNV activity with a sensitivity of 97.8% and a specificity of 85.4%. Conclusion: In PM-MNV, a novel comprehensive diagnostic method combining EZ interruption, ELM elevation, and RPE interruption might be a valuable indicator to evaluate PM-MNV activity.

Factors associated with the recurrence of choroidal neovascularization in pathologic myopia.

Purpose: To investigate the factors associated with the recurrence of pathologic myopia choroidal neovascularization (PM-CNV). Methods: Forty-eight eyes of 48 patients with PM-CNV treated with conbercept at least 6 months of follow-up were included. Appearance of ellipsoid zone (EZ) and retinal pigment epithelium (RPE) observed on optical coherence tomography (OCT). Hyperreflective foci (HRF) height measured on OCT. Observation of CNV shape on OCT-angiography (OCTA). PM-CNV area measured on OCTA. To observe relationship between these factors and best corrected visual acuity (BCVA) and PM-CNV recurrence. Results: The 48 patients (48 eyes) with PM-CNV were divided into two groups: yielding a group of 20 eyes with type 1 and a group of 28 eyes with type 2. The BCVA of type 1 was better than type 2 before and after treatment (P < 0.005). Smaller HRF height (P < 0.001) and CNV area (P < 0.001) for type 1 than type 2. The appearance of EZ and RPE were intact (P < 0.001). Spearman correlation analysis found that final BCVA was significantly associated with baseline BCVA, HRF height, and appearance of EZ (P < 0.05). Binary logistics regression analysis revealed that PM-CNV recurrence was significantly correlated not only HRF height and CNV area, but also with appearance of EZ, and RPE (P < 0.05). Conclusion: PM-CNV had a higher recurrence ratio. Baseline BCVA and clinical features play an important role for vision prognosis. Factors associated with PM-CNV recurrence include HRF height, CNV area, and changes in EZ and RPE structure.