Optical Coherence Tomography Angiography Assessment of Macular Choriocapillaris and Choroid Following Panretinal Photocoagulation in a Diverse Population With Advanced Diabetic Retinopathy

Aflibercept 5+PRN with retinal laser photocoagulation is more effective than retinal laser photocoagulation alone and aflibercept 3+PRN with retinal laser photocoagulation in patients with high-risk proliferative diabetic retinopathy and diabetic macular edema: a 12-month clinical trial

Objective

This study aimed to investigate and compare the efficacy and safety of retinal laser photocoagulation (PRP) alone, PRP with aflibercept 3+PRN, and PRP with aflibercept 5+PRN in patients with both high-risk proliferative diabetic retinopathy (PDR) and diabetic macular edema (DME).

Methods

Overall, 170 patients with high-risk PDR and DME (170 eyes from 170 patients) who visited our ophthalmology clinic from December 2018 to December 2020 were divided into the PRP (n=58), aflibercept 5+PRN with PRP (n=53), and aflibercept 3+PRN with PRP (n= 59) groups. General information, such as age, sex, and eye category, was obtained. Moreover, best-corrected visual acuity (BCVA), baseline central macular foveal thickness (CFT), microaneurysm (MA), area of neovascularization (NV), area of hard exudate (HE), and cytokine levels in atrial fluid before and after treatment, were assessed. The χ2 test was used for comparison between groups for statistical data. Analysis of variance was used for the statistical description of measurement data, independent samples were analyzed using Student's t-test, and Student-Newman-Keuls test was used for group comparisons. Differences were considered statistically significant at P < 0.05.

Results

After treatment, no significant improvement in the BCVA (logMAR) of patients in the PRP group was observed. The BCVA (log MAR) decreased from 0.72 ± 0.17 and 0.74 ± 0.17 to 0.50 ± 0.13 and 0.53 ± 0.17 in PRP with aflibercept 5+PRN and PRP with aflibercept 3+PRN groups, respectively, with a statistically significant difference compared to those in the PRP group (P<0.05 in all cases). However, no statistically significant difference was observed between the combined treatment groups (P>0.05). The CFT in the PRP-only group decreased slightly from 361.80 ± 36.70 μm to 353.86 ± 40.88 μm, with no statistically significant difference (P>0.05), whereas the CFT in the aflibercept 5+PRN with PRP and aflibercept 3+PRN with PRP groups decreased from 356.57 ± 37.57 μm and 358.17 ± 44.66 μm to 284.87 ± 31.52 μm and 303.19 ± 37.00 μm, respectively, with statistically significant differences before and after treatment (P<0.05 for both groups). Statistically significant differences were observed in CFT between the three groups after treatment (P<0.05 in all cases). The number of MA (pcs) in the PRP, aflibercept 5+PRN with PRP, and aflibercept 3+PRN with PRP groups decreased from 118.34 ± 27.96, 118.60 ± 33.34, and 116.59 ± 28.95 to 92.95 ± 29.04, 44.60 ± 20.73, and 54.26 ± 25.43, respectively. The two-way comparison of the three groups revealed statistically significant differences in MA (P<0.05 in all cases). In the three groups, NV decreased from 1.00 ± 0.21 mm², 1.01 ± 0.18 mm², and 0.98 ± 0.20 mm² before treatment to 0.49 ± 0.17 mm², 0.31 ± 0.16 mm², and 0.38 ± 0.14 mm², respectively, with statistically significant differences (P<0.05 in all cases). After 12 months of treatment, 13, 18, and 18 patients had reduced HE area in the PRP-only, aflibercept 5+PRN with PRP, and aflibercept 3+PRN with PRP groups, respectively, with statistically significant differences (P<0.05 in all cases). After 12 months of treatment, vascular endothelial growth factor, monocyte chemoattractant protein-1, and glial fibrilliary acidic protein levels (pg/mL) in the aqueous humor decreased in both combined treatment groups compared with that at baseline, with statistically significant differences; however, no significant difference was observed between the two combined treatment groups (P>0.05).

Conclusion

Aflibercept 5+PRN combined with PRP was safe and effective in treating patients with high-risk PDR and DME, and was more effective than PRP-only and aflibercept 3+PRN with PRP in improving CFT and MA.

Optical Coherence Tomography Angiography as a Diagnostic Tool for Diabetic Retinopathy

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus, leading to visual impairment if left untreated. This review discusses the use of optical coherence tomography angiography (OCTA) as a diagnostic tool for the early detection and management of DR. OCTA is a fast, non-invasive, non-contact test that enables the detailed visualisation of the macular microvasculature in different plexuses. OCTA offers several advantages over fundus fluorescein angiography (FFA), notably offering quantitative data. OCTA is not without limitations, including the requirement for careful interpretation of artefacts and the limited region of interest that can be captured currently. We explore how OCTA has been instrumental in detecting early microvascular changes that precede clinical signs of DR. We also discuss the application of OCTA in the diagnosis and management of various stages of DR, including non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), diabetic macular oedema (DMO), diabetic macular ischaemia (DMI), and pre-diabetes. Finally, we discuss the future role of OCTA and how it may be used to enhance the clinical outcomes of DR.

Optical Coherence Tomography Angiography Changes in Macular Area in Patients with Proliferative Diabetic Retinopathy Treated with Panretinal Photocoagulation

BACKGROUND

The purpose of this study was to investigate the changes in macular microvasculature using optical coherence tomography angiography (OCTA) in association with functional changes in patients with proliferative diabetic retinopathy (PDR) treated with panretinal photocoagulation (PRP) with a follow up of 12 months.

METHODS

The participants in this study were 28 patients with PDR and no macular oedema, who were eligible for PRP. All participants underwent best-corrected visual acuity (BCVA) measurement, optical coherence tomography (OCT), and OCT angiography (OCTA) at baseline (before treatment) and at months 1, 6, and 12 after the completion of PRP treatment. The comparison of OCTA parameters and BCVA between baseline and months 1, 6, and 12 after PRP was performed.

RESULTS

There was a statistically significant decrease in foveal avascular zone (FAZ) area at months 6 and 12 of the follow-up period compared to baseline (p = 0.014 and p = 0.011 for month 6 and 12, respectively). Of note is that FAZ became significantly more circular 6 months after PRP (p = 0.009), and remained so at month 12 (p = 0.015). There was a significant increase in the mean foveal and parafoveal vessel density (VD) at all quadrants at the superficial capillary plexus (SCP) at month 6 and month 12 after PRP compared to baseline. No difference was noticed in VD at the deep capillary plexus (DCP) at any time-point of the follow up. BCVA remained the same throughout the follow-up period.

CONCLUSIONS

At months 6 and 12 after PRP, foveal and parafoveal VD at SCP significantly increased compared to baseline, while the FAZ area significantly decreased and FAZ became more circular.

Choriocapillaris and progressive ganglion cell-inner plexiform layer loss in non-glaucomatous eyes

AIMS

To explore the relationship between choriocapillaris (CC) flow deficit percentage (FD%) and ganglion cell-inner plexiform layer (GCIPL) thickness in a population-based sample of non-glaucomatous eyes.

METHODS

This is a longitudinal cohort study and prospective cross-sectional study. Non-glaucoma Chinese subjects aged 18 years or older were enrolled. All participants underwent a detailed ophthalmic examination, including swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography. Average, inner average, outer average and nine Early Treatment Diabetic Retinopathy Study sub-regions of GCIPL thickness and CC FD% were measured. The correlation between CC FD% and GCIPL was assessed using a linear regression model, and the relationship between the rate of change of GCIPL thickness and CC FD% was further validated in a 2year longitudinal study.

RESULTS

In the cross-sectional study including 3514 participants (3514 non-glaucoma eyes), a higher CC FD% was significantly associated with a thinner GCIPL (β=-0.32; 95% CI -0.43 to -0.21; p<0.001). Further, in a longitudinal study (453 eyes of 453 participants), a faster increase in CC FD% was found to be significantly associated with a faster decrease in GCIPL thickness (β=-0.10; 95% CI -0.17 to -0.03; p=0.004) after adjusting for age, sex, axial length and image quality score.

CONCLUSIONS

This is the first time to show that CC FD% and GCIPL thickness were correlated in both cross-sectional and longitudinal studies of non-glaucomatous individuals, which may potentially provide further insights on the role of CC perfusion in glaucoma development and progression.

Retinal and Choroidal Alterations in Diabetic Retinopathy Treatment using Subthreshold Panretinal Photocoagulation with Endpoint Management Algorithm: A Secondary Analysis of a Randomized Clinical Trial

INTRODUCTION

The aim of this study was to compare retinal and choroidal alterations in eyes with severe nonproliferative diabetic retinopathy (NPDR) after panretinal photocoagulation (PRP), using conventional pattern scan laser (PASCAL) and PASCAL with endpoint management (EPM).

METHODS

This was a post hoc analysis of a paired randomized clinical trial. Bilateral treatment-naïve eyes of an individual with symmetric severe NPDR were randomly allocated into the threshold PRP group and subthreshold EPM PRP group. Patients had follow-up visits at 1, 3, 6, 9, and 12 months post-treatment. The retinal thickness (RT), choroidal thickness (CT), choroidal area, and choroidal vascularity index (CVI) were compared between the two groups and among different time points within the same group.

RESULTS

Seventy eyes of 35 patients with diabetes mellitus (DM) were finally included for analysis at the 6- and 12-month visits, respectively. At 3 and 6 months post-treatment, the RT in the subthreshold EPM PRP group was significantly thinner than that in the threshold PRP group. CT, stromal area, and luminal area were reduced earlier in the threshold PRP group than in the subthreshold EPM PRP group. CVI was not significantly different within the same group or between groups at most time points.

CONCLUSION

At 12 months post-treatment, retinal thickening and choroidal disturbance may be slightly less severe and more delayed in eyes receiving PRP using PASCAL with EPM than in those receiving PRP using conventional PASCAL. The EPM algorithm may be a good alternative in PRP when treating severe NPDR.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01759121.

Effect of panretinal photocoagulation on retina and choroid in diabetic retinopathy: An optical coherence tomography angiography study

BACKGROUND

To analyze the quantitative changes in both macular, and choroidal thickness, and microvascularization after panretinal photocoagulation (PRP) in eyes with proliferative diabetic retinopathy (PDR) or severe non-proliferative diabetic retinopathy (NPDR) by using optical coherence tomography angiography (OCT-A).

METHODS

The patients diagnosed with severe NPDR or PDR according to the Early Treatment Diabetic Retinopathy Study (ETDRS) and decided to be treated with PRP were included in this prospective and observational study. Ten eyes of 10 patients with PDR and twelve eyes of 12 patients with severe NPDR were examined. Macular scans (6 × 6 mm) were obtained from OCT-A at baseline and at month 6 after PRP. Subfoveal choroidal thickness (SFCT) measurements that were obtained through the foveolar center on a high-definition line scan were recorded.

RESULTS

Best-corrected visual acuity (BCVA) significantly decreased (p = 0.018), central foveal thickness and mean parafoveal thickness significantly increased (p < 0001 and p < 0.001, respectively) six months after PRP. The thickness of all parafoveal retinal quadrants (temporal, superior, nasal, inferior) increased (p = 0.001, p = 0.003, p < 0.001, p < 0.001, respectively) and mean parafoveal, parafoveal temporal, and parafoveal nasal vessel density of the deep capillary plexus (DCP) significantly decreased six months after PRP compared with the baseline values (p = 0.023, p = 0.041, p = 0.018, respectively).

CONCLUSIONS

The parafoveal vessel density of DCP decreased significantly 6 months after PRP in eyes with PDR or severe NPDR. While the difference in SFCT and choroidal flow density was not significant from the baseline; central and parafoveal retinal thickness increased and BCVA decreased significantly 6 months after PRP treatment.

Macular vessel density before and after panretinal photocoagulation in patients with proliferative diabetic retinopathy

Introduction

Diabetic retinopathy (DR) is microangiopathy causing ischemia leading to proliferative diabetic retinopathy and macular edema. Panretinal photocoagulation (PRP) reverses the ischemia leading to regression of neovessels. Most previous studies showed the large vessel effects of PRP, while optical coherence tomography angiography (OCTA) allowed noninvasive quantification of microvascular retinal changes.

Aim

To study the effect of PRP on microvascular retinal vessels in a detailed manner at different retinal and choroidal levels using OCTA.

Patients and methods

This study was a prospective interventional study. 30 eyes of 18 diabetic patients with PDR were included. All patients were evaluated clinically and with OCTA (Avanti RTVue-XR system, Optovue) to evaluate superficial and deep vessels density (VDs), choroidal flow, and FAZ area before PRP (base line) and 1 month and 6 months after PRP.

Results

PRP improved vessels density at superficial (SCP), deep (DCP), and choriocapillaris levels. Foveal vessel density at SCP and DCP were statistically significantly increased. SCP was 28.76 ± 2.56 at base line and was increased to 29.84 ± 2.47 and 30.89 ± 2.20 after 1 month and after 6 months, respectively. DCP was 34.08 ± 5.59 at base line and was increased to 34.93 ± 5.66 and 36.09 ± 5.62 after 1 month and after 6 months, respectively. Foveal choriocapillaris was statistically significantly increased from 63.04 ± 2.66 at base line to 63.48 ± 2.65 and 63.98 ± 2.78 after 1 month and 6 months, respectively. Choroidal flow was increased from 1.74 ± 0.07 at base line to 1.75 ± 0.09 at 1 month which was nonsignificant (P = 0.72), but it was significantly increased to 1.87 ± 0.27 6 months after PRP (P = 0.009). FAZ area was significantly improved after PRP. FAZ area was decreased from 0.56 ± 0.27 at base line to 0.50 ± 0.21 after 1 month and to 0.46 ± 0.21 after 6 months.

Conclusion

OCTA parameters were significantly improved by PRP in PDR patients, possibly due to redistribution of blood in occluded capillary plexuses.

Trials registry: NCT04976361.

Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

PURPOSE

To evaluate the ocular and systemic determinants of the choriocapillaris flow deficits percentage (CC FD%) in normal eyes.

DESIGN

Observational cross-sectional study.

METHODS

Healthy Chinese participants without ocular or systemic diseases underwent detailed ophthalmic evaluations, including swept-source optical coherence tomography angiography (SS-OCTA) with 6- × 6-mm macular choriocapillaris images. The CC FD% was assessed in circular regions with diameters of 1.0 and 5.0 mm, rings with 1.0- to 2.5-mm diameters, and rings with 2.5- to 5.0-mm diameters.

RESULTS

The study included 830 individuals (mean ± SD age 58.66 ± 8.75 years). CC FD% (mean ± SD 22.05% ± 1.13%) was the lowest in the 2.5- to 5.0-mm ring, followed by the 1.0- to 2.5-mm ring, and highest in the 1.0-mm circle. In multivariable analysis, a higher CC FD% was associated with older age (β = 0.16 [95% confidence interval {CI}] 0.08-0.24, P < .001), higher intraocular pressure (β = 0.34 [95% CI 0.25-0.42], P < .001), higher serum concentrations of high-density lipoprotein cholesterol (β = 0.24 [95% CI 0.17-0.32], P < .001), and lower image quality score (β = -0.22 [95% CI -0.30 to -0.14], P < .001). CC FD% was also independent of axial length.

CONCLUSIONS

In healthy adult Chinese individuals, a higher CC FD% was associated with older age, higher intraocular pressure, and higher high-density lipoprotein cholesterol serum concentration. These factors may influence clinical assessments of the choriocapillaris. The lack of an association between CC FD% and axial length is consistent with similar findings for Bruch membrane thickness, macular retinal thickness, and macular retinal pigment epithelium cell density.