Effect of axial length on peripapillary microvasculature: An optical coherence tomography angiography study

The repeatability of macular and peripapillary vessel density in participants with different severities of glaucoma

PURPOSE

To investigate the repeatability of optical coherence tomography angiography (OCTA) parameters in participants with different severities of glaucoma.

METHODS

Subjects with open-angle glaucoma were enrolled prospectively and categorised into mild (mean deviation [MD] of 24-2 visual field test ≥ -6 dB), moderate to advanced (-6 > MD ≥ -20 dB) and severe glaucoma groups (MD < -20 dB). OCTA was performed three times within a single visit to obtain superficial and deep macular vessel density (VD) and peripapillary vessel and capillary density. The association between the coefficient of variation (CoV) and intraclass correlation coefficient (ICC) of these OCTA parameters and glaucoma severity (MD, the thickness of the retinal nerve fibre layer and the ganglion cell complex) was analysed, along with factors associated with the CoV of OCTA parameters.

RESULTS

A total of 57 mild, 92 moderate to advanced and 39 severe glaucomatous eyes were included. CoV for superficial (p < 0.001) and deep macular VD (p < 0.001) and peripapillary VD (p = 0.004) increased with glaucoma severity. Greater CoV for superficial and deep macular VD and peripapillary VD was associated with worse MD and scan quality index in multivariable analysis. The association between a higher CoV of superficial and deep macular VD and worse MD was only noticeable in participants with a scan quality index <7. The relationship between the CoV of peripapillary VD and MD was consistent across varying image qualities.

CONCLUSION

The intrasession variability of OCTA parameters was greater in glaucoma participants with advanced disease, especially in those with suboptimal scan quality.

Association of childhood obesity on retinal microvasculature and the role of biochemical markers for its early detection

BACKGROUND

Childhood obesity is a growing public health concern, associated with several systemic disorders including changes in retinal microvasculature. This study aims to assess the relationship between body composition, biochemical markers, and retinal microvascular changes in obese children.

METHODS

In this cross-sectional study, 45 overweight and obese children and 46 age- and sex-matched healthy individuals were evaluated. In addition to physical examination, anthropometric measurements were obtained using a body composition analyzer. A comprehensive ophthalmic assessment was conducted for all participants, which included advanced optical biometry, autorefractometry, visual acuity testing, and slit-lamp examination. Retinal microvasculature was assessed using optical coherence tomography angiography (OCT-A). Biochemical markers, including lipid profile, liver function tests, and CRP (as marker of inflammation), were also analyzed.

RESULTS

The mean ages were 10.18 and 9.40 years in the obese/overweight and normal weight groups, respectively. Increased foveal thickness (p = 0.04) and foveal vessel density (p = 0.01) in the superficial capillary plexus, and decreased vessel density in the inferior parafoveal region of the deep capillary plexus (p = 0.03) were observed in obese/overweight children. Adjusted and crude regression analysis showed significant associations between body mass index, percent body fat, fasting blood glucose, and serum alanine transaminase levels with foveal vessel density, as well as between body mass index and serum triglycerides levels with foveal thickness.

CONCLUSIONS

Our findings suggest that childhood obesity is associated with significant alterations in retinal microvasculature. We propose that retinal health assessments and biochemical evaluations be considered in the clinical management of obese children.

Corneal higher-order aberrations and their relationship with choroid in myopic patients

BACKGROUND

To investigate corneal higher-order aberrations (HOAs) and choroidal characteristics in myopic individuals and explore the association between HOAs and choroidal parameters.

METHODS

Myopic participants were categorized into three groups based on axial lengths (ALs). We compared corneal HOAs, including spherical (Z40), comatic (Z3 - 1 and Z31), and trefoil (Z3 - 3 and Z33) aberrations, as well as choroidal vascularity index (CVI) and choroidal thickness (CT). Linear regression analysis was used to assess the relationships among corneal HOAs, CVI, CT, spherical equivalent, and AL.

RESULTS

Groups 1, 2, and 3 included 105, 98, and 118 eyes, respectively. Group 3 exhibited lower spherical HOA root mean square and Z40 values than group 1(p < 0.05). Group 1 showed lower Z31 levels than other groups (p < 0.001). Groups 1 and 2 had higher mean, central, and I2 vertical CVIs than group 3 (p < 0.05). Group 1 had a larger vertical S1 CVI than group 3 (p < 0.05). Group 3 had smaller horizontal CVI values in all regions except N2 (p < 0.05). Both the mean and CT in all regions decreased as AL increased (p < 0.001). The comatic (Z31) and trefoil (Z33) components were predictors of mean horizontal CVI, and the comatic (Z31) component was correlated with both mean vertical and horizontal CT.

CONCLUSION

Longer AL myopic patients exhibited lower absolute values of spherical aberration and horizontal coma. Alterations in choroid in myopic patients correlated with corneal HOAs. Our results suggest a potential connection between the optical quality and ocular perfusion in myopia.

Vessel density on optical coherence tomography angiography is prognostic for future disease course in intermediate uveitis

As most rare diseases, intermediate uveitis lacks reliable endpoints necessary for randomized clinical trials. Therefore, we investigated longitudinal changes of retinal and choriocapillaris perfusion on optical coherence tomography angiography (OCT-A) in intermediate uveitis and their prognostic value for future best corrected visual acuity (BCVA) and central retinal thickness (CRT). In this retrospective, longitudinal cohort study eyes of patients with intermediate uveitis were imaged by swept-source OCT-A (macula-centered 3 × 3 mm; PLEX Elite 9000, Zeiss) and stratified into clinically stable, worsened and improved based on changes in clinical parameters. Superficial (SRL) and deep retinal layers (DRL) were automatically analyzed for vessel density (VD) and choriocapillaris layer for non-perfused area (CCNPA) using ImageJ. Mixed-effects regression analysis controlling for age, sex, and OCT-A signal strength index (SSI) was used to evaluate the prognostic value of OCT-A parameters. 91 eyes (62 stable, 12 worsened, and 17 improved) were included in the analysis and mean follow-up time was 296 days. Longitudinal changes of VD were different between all three groups (p = 0.002 for SRL and p = 0.017 for DRL). Clinically worsened eyes showed a decrease in VD (- 0.032 ± 0.055 for SRL and - 0.027 ± 0.025 for DRL), whereas clinically improved eyes showed an increase in VD (0.037 ± 0.039 for SRL and 0.001 ± 0.023 for DRL). No difference was found for CCNPA. When controlling for age, sex, and SSI, observed differences held true in clinically worsened eyes for DRL (p = 0.011) and in clinically improved eyes for SRL (p = 0.002). An increase of CCNPA in clinically worsened eyes (p = 0.03) compared to clinically stable and improved eyes was evident. Predictive analysis revealed an association of VD in SRL and DRL at baseline with BCVA at follow-up (p = 0.039 and p = 0.047, respectively) and of VD in SRL at baseline with CRT at follow-up (p = 0.046). Alterations in retinal perfusion on OCT-A in intermediate uveitis are partly reversible and OCT-A VD may serve to predict future BCVA and CRT. Thus, perfusion parameters on OCT-A might aid monitoring and serve as prognostic imaging-biomarker.

Application of Artificial Intelligence to Quantitative Assessment of Fundus Tessellated Density in Young Adults with Different Refractions

INTRODUCTION

The aim of this study was to quantitatively assess fundus tessellated density (FTD) and associated factors by artificial intelligence (AI) in young adults.

METHODS

A total of 1,084 undergraduates (age, 17-23 years old) were enrolled in November 2021. The students were divided into three groups according to axial length (AL): group 1 (AL <24.0 mm, n = 155), group 2 (24 mm ≤ AL <26 mm, n = 578), and group 3 (AL ≥26 mm, n = 269). FTD was calculated by extracting the fundus tessellations as the regions of interest (circle 1, diameter of 3.0 mm; circle 2, diameter of 6.0 mm) and then calculating the average exposed choroid area per unit area of fundus.

RESULTS

Among 1,084 students, 1,002 (92.5%) students' FTDs were extracted. The mean FTD was 0.06 ± 0.06 (range, 0-0.40). In multivariate analysis, FTD was significantly associated with male sex, longer AL, thinner subfoveal choroid thickness (SFCT), increased choriocapillaris vessel density (VD), and decreased deeper choroidal VD (all p < 0.05). In circle 1 (diameter of 3.0 mm) and circle 2 (diameter of 6.0 mm), analysis of variance showed that the FTD of the nasal region (p < 0.05) was significantly larger than that of the superior, inferior, and temporal regions.

CONCLUSION

AI-based imaging processing could improve the accuracy of fundus tessellation diagnosis. FTD was significantly associated with a longer AL, thinner SFCT, increased choriocapillaris VD, and decreased deeper choroidal VD.

Assessment of the Retinal Vessels in Keratoconus: An OCT Angiography Study

This study investigated vascular density and foveal avascular zone (FAZ) parameters using optical coherence tomography angiography (OCT-A) in patients with keratoconus (KC). Participants with KC and healthy controls were included and underwent best-corrected visual acuity (BCVA), keratometry, anterior segment OCT, and macular OCT-A examinations. Of the 70 subjects (mean age 42.9 ± 15.31 years), 79 KC and 47 healthy eyes were included. Significant reductions in the KC group were recorded for the FAZ area, with a mean (±SD) of 0.19 ± 0.12 vs. 0.25 ± 0.09 mm2 p < 0.001. Central vascular density in KC patients was lower compared with the controls: 6.78 ± 4.74 vs. 8.44 ± 3.33 mm−1 p = 0.049; the inner density was also decreased in the study group (13.64 ± 5.13 vs. 16.54 ± 2.89 mm−1, p = 0.002), along with the outer density (14.71 ± 4.12 vs. 16.88 ± 2.42 mm−1, p = 0.004) and full density (14.25 ± 4.30 vs. 16.57 ± 2.48) p = 0.003. Furthermore, BCVA was positively correlated with central vascular density (R = 0.42 p = 0.004, total R = 0.40, p = 0.006) and inner density (R = 0.44, p = 0.002) in patients with KC but not in controls. Additionally, we found a correlation between K2 and inner vascular density (R = −0.30, p = 0.043) and central epithelium thickness and outer density (R = 0.03, p = 0.046). KC patients had lower macular vascular density and a smaller FAZ than healthy participants. The BCVA in KC patients was correlated with the vascular density.