Retinal nerve fiber layer thickness and radial peripapillary capillaries density in myopic adults with optical coherence tomography angiography.

PURPOSE: To evaluate retinal nerve fiber layer thickness (RNFLT) and radial peripapillary capillaries (RPC) density in adults with different degrees of myopia using optical coherence tomography angiography (OCTA) and explore their relationship with ocular factors, such as axial length (AL) and disc area. METHODS: A total of 188 subjects were included in this cross-sectional study. The eyes were divided into four groups according to AL. OCTA was used for the assessment of RNFLT, RPC density, and other optic disc measurements, such as disc area. One-way analysis of variance was performed to compare differences between four groups, and P value < 0.01 was considered significant. RESULTS: The RNFLT was significantly thinner in high myopia (HM) group at inferior nasal (IN) quadrant (P = 0.004) than low myopia (LM) group, but thicker at temporal inferior (TI) quadrant (P = 0.006). The RPC density of nasal superior (NS) quadrant, nasal inferior (NI) quadrant, and inferior nasal (IN) quadrant significantly decreased as AL increasing. By simple linear regression analysis, the inside disc RPC (iRPC) density tended to be correlated significantly with AL (0.3997%/mm, P < 0.0001). Peripapillary RPC (pRPC) density was in significant correlation with AL (-0.2791%/mm, P = 0.0045), and peripapillary RNFLT (pRNFLT) was in significant correlation with disc area (0.2774%/mm2, P = 0.0001). CONCLUSION: RNFLT and RPC density were closely associated with AL and disc area. They might be new indexes in assessing and detecting myopia development via OCTA.

Does the ISNT rule apply to the radial peripapillary capillary vessel density in OCT angiography?

PURPOSE: To investigate the applicability of ISNT (inferior ≥ superior ≥ nasal ≥ temporal), IST (inferior ≥ superior ≥ temporal), and T min (temporal quadrant with the minimum value) rules to the peripapillary nerve fiber layer (NFL) thickness and radial peripapillary capillary (RPC) vessel density (VD) using Optical Coherence Tomography (OCT) and OCT angiography (OCT-A). MATERIALS AND METHODS: This cross-sectional study included 134 eyes of 74 healthy individuals. NFL thickness and RPC VD were measured in all four quadrants using OCT and OCT-A in order to determine the number of eyes that obey the ISNT, IST, and T min rules. RESULTS: Mean age was 48.8 ± 15.5 (range 25-82) years. The ISNT rule was valid in 52 eyes (38.81%) on OCT and only 12 eyes (8.95%) on OCT-A scans. The IST rule was followed by 83 (61.94%) and 37 (27.61%) eyes on OCT and OCT-A scans respectively. The T min rule was valid in 86 eyes (64.18%) in OCT scans and in 26 eyes (19.4%) in OCT-A scans. CONCLUSION: The topography of the RPC network does not obey the ISNT rule in healthy eyes. The ISNT rule and its variants were found to be more relevant in OCT NFL thickness measurements compared to OCT-A RPC VD measurements.

Microvascular and structural alterations in the optic nerve head of advanced primary open-angle glaucoma compared with atrophic non-arteritic anterior ischemic optic neuropathy.

PURPOSE: This cross-sectional study compared the peripapillary vessel density (VD), peripapillary retinal nerve fiber layer (RNFL) thickness, and optic nerve head (ONH) parameters between eyes with atrophic non-arteritic anterior ischemic optic neuropathy (NAION) and eyes with advanced primary open-angle glaucoma (POAG) matched for visual field mean deviation. METHODS: Peripapillary VDs and RNFL thicknesses in the peripapillary region, and 4 sectors (superior, inferior, nasal, and temporal), and scanning laser ophthalmoscopy parameters of the ONH were evaluated with optical coherence tomography angiography (OCTA) among 21 atrophic NAION cases, 26 advanced POAG cases, and 30 age- and sex-matched healthy controls. RESULTS: The POAG eyes had lower peripapillary VDs in all areas compared with the NAION eyes, which was most marked in the inferior and nasal sectors (p=0.005 for both). RNFL loss was similar between the 2 groups in all areas, except for a preserved thickness in the inferior sector in NAION eyes (p=0.01). Peripapillary VD demonstrated stronger correlations with global RNFL thickness in the peripapillary region in the NAION eyes compared with that of the POAG eyes (r=0.91 p<0.00001, r=0.42 p=0.03 respectively). In multivariate analysis, the peripapillary VD correlated with age and RNFL thickness in the POAG eyes while it correlated with SSI and RNFL thickness in the NAION eyes. CONCLUSIONS: A tendency for a lower peripapillary VD despite similar visual field mean deviation values may infer a more prominent role of the vascular regression in POAG compared with NAION.

Quantitative Analysis of the RPC Vessel Density and the RNFL Thickness in Patients with Type 2 Diabetes Mellitus by Using OCT Angiography.

INTRODUCTION: This study aims to compare the structural differences in the optic disc blood perfusion and the peripapillary retinal nerve fibre layer (pRNFL) thickness in age-matched healthy subjects and patients with type 2 diabetes mellitus (DM) by using quantitative analysis with optical coherence tomography angiography (OCTA). METHODS: A cross-sectional cohort study on patients with type 2 DM with or without diabetic retinopathy (DR) and healthy subjects was conducted. The 4.5-mm scanning angio-disc pattern of the OCTA system was used to assess the optic disc. The analysed indices included radial peripapillary capillary (RPC) vessel density and pRNFL thickness. RESULTS: A total of 78 eyes from 78 patients with type 2 DM, including 27 without clinical DR (NDR), 26 with non-proliferative DR (NPDR), and 25 with proliferative DR (PDR), and 28 age-matched healthy subjects were enrolled. The average RPC vessel density of the whole (p < 0.001) and the peripapillary (p < 0.001) regions was significantly different in different groups, whereas the pRNFL was not statistically significant (p = 0.764). Compared with that in healthy subjects, the RPC vessel densities in 4, 5, and 8 peripapillary sectors in NDR (all p < 0.05), NPDR (all p < 0.05), and PDR (all p < 0.05) groups, respectively, were reduced. Compared with that in healthy subjects, the pRNFL thickness significantly decreased in the inferior nasal sector (p = 0.001) in NDR but significantly increased in the 2 sectors (all p < 0.01) in PDR. The DR severity was negatively correlated with the peripapillary RPC vessel density (r = -0.583, p < 0.001) but had no correlation with the pRNFL thickness (r = -0.045, p = 0.648). The positive correlation between the peripapillary RPC vessel density and the pRNFL thickness was statistically significant in the control (r = 0.531, p = 0.004), NDR (r = 0.528, p = 0.004), and NPDR (r = 0.405, p = 0.040) groups but not in the PDR group (r = 0.394, p = 0.05). CONCLUSIONS: The peripapillary RPC perfusion decreased with DR aggravation, which may be considered as a useful indicator of DR severity. However, the pRNFL thickness had little diagnostic power in differentiating healthy and DM eyes.

Sectorwise analysis of peripapillary vessel density and retinal nerve fiber layer thickness in exfoliation syndrome.

PURPOSE: This cross-sectional study compared the peripapillary vessel density and retinal nerve fiber layer (RNFL) thickness in patients with exfoliation syndrome (XFS) and healthy controls for evaluation of the early structural and vascular alterations in XFS. METHODS: One eye was included from 75 patients with XFS and 54 healthy controls. The patients with XFS were matched the controls for age, intraocular pressure and axial length. The vascular density of the radial peripapillary capillaries (RPCs) and the peripapillary RNFL thickness were evaluated with optical coherence tomography angiography. RESULTS: The mean peripapillary RNFL thicknesses of the groups were similar in all sectors (p > 0.05 for all). However, eyes with XFS demonstrated lower mean peripapillary vessel densities in all areas (p < 0.05 for all) except for the nasal sector (p = 0.68) compared to the controls. The gradual age correlated decline in the peripapillary RNFL thickness and the RPC vessel density observed in the healthy eyes was absent in XFS (r = - 0.14 p = 0.65 and r = - 0.23 p = 0.05). CONCLUSIONS: Alterations in the peripapillary vascular density despite a preserved RNFL thickness in XFS supports the hypothesis that vascular alterations may precede structural alterations and have an important role in the pathogenesis of XFS. XFS may have different effects on the microvasculature of different peripapillary areas, with the nasal sector being mostly preserved.

Effect of silicone oil on peripapillary capillary density in patients with rhegmatogenous retinal detachment.

PURPOSE: To evaluate the effect of silicone oil (SO) on peripapillary blood flow using OCT angiography. METHODS: This prospective case series recruited patients with unilateral rhegmatogenous retinal detachment (RRD) who underwent vitrectomy and SO tamponade. Patients were examined before SO removal and at 10 days, 1 month, and 3 months after SO removal on a spectral domain OCT angiography device (RTVue XR Avanti, Optovue Inc., CA, USA) for the measurement of radial peripapillary capillaries (RPC) vessel density (VD) in global field, superior hemifield, and inferior hemifield. Changes in RPC VD following SO removal were compared between affected eyes and contralateral eyes. RESULTS: Twenty-two patients were analyzed. The average duration of SO tamponade was 101.3 days (range, 90 to 119 days). After SO removal, global RPC VD increased by 1.3% (95%CI, 0.3 to 2.3%), compared with a - 0.4% (95%CI, - 1.4 to 0.7%) change in contralateral eyes (P = 0.007). The increase in RPC VD after SO removal mainly occurred in the superior hemifield, which was 1.6% (95%CI, 0.6 to 2.7%). The increase in RPC VD in the inferior hemifield was 1.0% (95%CI, - 0.2 to 2.1%) after SO removal. CONCLUSIONS: We detected a mild increase in peripapillary capillary density after SO removal, mainly in the superior hemifield. Our results suggested that SO tamponade could have negative effect on peripapillary blood flow, possibly by capillary compression.

Optical coherence tomography angiography analysis of fabry disease.

PURPOSE: Fabry disease (FD) is characterized by a deficiency in α-galactosidase A activity that leads to the cumulative deposition of unmetabolized glycosphingolipids within organs, including the vascular endothelium and the eyes. The purpose of this study was to assess the effects of FD on the retinal microvasculature, foveal avascular zone (FAZ), macular thickness and retinal nerve fiber layer (RNFL) using optical coherence tomography angiography (OCT-A). METHODS: Twenty-five patients (14 female and 11 male; mean age 33.16 ± 11.44) with genetically verified FD were compared with 37 age- and sex-matched healthy controls (mean age 32.36 ± 15.54). The vessel density (VD) values of the superficial and deep capillary plexuses (SCP and DCP), the area of the FAZ, the density of radial peripapillary capillaries (RPC), the macular thickness and the retinal nerve fiber layer thickness were measured by OCT-A examination. RESULTS: The patients showed significantly lower VD values than controls in the foveal regions of both SCP and the DCP (21.15 ± 5.56 vs. 23.79 ± 4.64 (p = 0.048), 37.92 ± 6.78 vs. 41.11 ± 5.59 (p = 0.048), respectively). The FAZ was significantly larger in the FD group than in the control group (0.3 ± 0.1 vs. 0.24 ± 0.08 (p = 0.011)). No significant difference was identified in measurements of RPC density, peripapillary RNFL thickness or macular thickness between the two groups (p > 0.05 for all). CONCLUSION: Decreased VD and an enlarged foveal avascular area suggest possible changes in the retinal microvasculature of patients with FD. OCT-A can serve as a useful, noninvasive, quantitative tool for diagnosing FD and monitoring its progression.

Associations between changes in radial peripapillary capillaries and occurrence of disc hemorrhage in normal-tension glaucoma.

PURPOSE: In order to clarify the association between peripapillary vascular changes and disc hemorrhage (DH) occurrences over time, we analyzed the density of radial peripapillary capillary (RPC) and clinical parameters during follow-up periods in patients with normal-tension glaucoma (NTG). METHODS: Seventy-seven eyes of 77 NTG patients were subjected to analysis. We selected patients who had an initial optical coherence tomography angiography (OCTA) scan in 2015 and who had another OCTA scan in 2018 with both OCTA scans showing good-quality images. We investigated the relationships between DH occurrence and each of the following parameters: RPC density, circumpapillary retinal nerve fiber layer (cpRNFL) thickness slope and total deviation (TD) slope. RESULTS: In the period between the initial and final OCTA, we categorized the patients into 53 sides with DH (DH group) and 101 sides without DH (non-DH group). The ΔRPC density of sides with DH was significantly greater than that of sides without DH (DH, - 4.42 ± 6.43%; without DH, - 2.48 ± 5.29%; p = 0.0469). The cpRNFL thickness slope of sides with DH was significantly faster than that of sides without DH (DH, - 2.85 ± 3.17; without DH, - 0.74 ± 2.46 µm/y; p < 0.0001). The TD slope of sides with DH was significantly faster than that of sides without DH (DH, - 0.50 ± 0.77; without DH, - 0.22 ± 0.53 dB/y; p = 0.0163). As DH occurrence increased, the RPC density significantly decreased (r = -0.255, p = 0.0014). Stepwise multiple regression analysis to identify factors influencing RPC changes showed that frequency of DH (ß = - 0.224, p = 0.008) and central corneal thickness (ß = - 0.220, p = 0.009) were significantly associated with RPC changes. CONCLUSIONS: DH occurrence may prompt the structural and vascular deterioration of NTG.

Purtscher's retinopathy case report: short posterior ciliary arteries contribution to radial peripapillary capillary system observed with optical coherence tomography angiography.

PURPOSE: The authors report a case of Purtscher's retinopathy whose optical coherence tomography angiography (OCT-A) analysis allows us to better understand the vascular network of the optic disk. METHODS: Case report. RESULTS: A 75-year-old man presented with vision loss in his left eye (LE) after chest compression. The best-corrected visual acuity (BCVA) in the LE was 20/200, and the anterior segment showed a relative afferent pupillary defect. Dilated fundus examination revealed white peripapillary retinal patches and macular hemorrhage. The OCT scan showed edema and hyper-reflectivity of the inner retinal layers at macular level. In turn, OCTA evidenced capillary dropout in both macular retinal plexus, though with preservation of the radial peripapillary capillaries (RPC) and choriocapillary layer. At 9 months, BCVA was 20/20 associated with persistence macular ischemia but unaffected RPC. CONCLUSION: In conclusion, this case suggests that the RPC does not depend exclusively on retinal capillaries as there was a reversible damage after a microvascular retinal disorder such as Purtscher's retinopathy. Possibly, the contribution from short posterior ciliary arteries ensures proper vascularization as choriocapillary layer also remained unaffected. Furthermore, OCTA is considered a useful tool that affords better assessment of RPC than FA.

Correlation between the radial peripapillary capillaries and the retinal nerve fibre layer in the normal human retina.

This study aims to provide evidence of the importance of radial peripapillary capillaries (RPCs) by quantitative study of the relationship between the RPCs and retinal nerve fibre layer (RNFL) in normal human donor eyes. The retinal microvasculature in eleven normal human donor eyes was perfused, fixed and labelled after cannulation of the central retinal artery. The retinas were dissected and whole-mounted for confocal microscopy. Six study regions were taken radially from the edge of the optic disc. RPCs from the optic disc edge to a radial distance up to 2.5 mm were imaged and their diameters, inter-capillary distance and volume occupation measured. These were correlated with the study region as well as thickness of the RNFL. It was found that the pooled average diameter of the RPCs in the first 2.5 mm from the optic disk was 8.9 µm. Significant differences in capillary diameter were present in the six regions, with larger diameter RPCs in the superior, inferior and nasal regions, and significantly smaller diameter in the temporal region. RPCs in the arcuate fibre regions extend the furthest from the optic disc, maintained a close inter-capillary distance for a longer distance than other regions, and have the highest RPCs volume occupancy. The RPCs volume was generally correlated with RNFL thickness. In conclusion, a close correlation between RNFL and RPCs presence has been demonstrated which is supportive of their functional reliance/co-dependence. The significantly smaller temporal RPCs may be a result of the greater presence of RPCs in the two bordering arcuate fibre regions and therefore a richer availability of nutrients diffusing from these two regions.

Assessment of OCT and Angio-OCT Parameters in Keratoconus Patients with and without Penetrating Keratoplasty.

Background/Objectives: Keratoconus (KC) is a bilateral eye disease characterized by corneal thinning and cone-like deformation, leading to visual impairment. This study evaluated the radial peripapillary capillaries (RPCs) in keratoconus patients with and without penetrating keratoplasty (PKP) using OCT and angio-OCT, comparing the results to a control group. Methods: This retrospective study included 149 eyes, 97 from patients who underwent PKP between January 2018 and February 2023 and 52 from patients who did not undergo PKP. The control group comprised 72 patients (144 eyes) who were healthy volunteers. Measurements included the best corrected visual acuity (BCVA), the intraocular pressure (IOP), slit-lamp biomicroscopy, a fundus examination, and corneal topography, as well as OCT and angio-OCT assessments of the RPCs, retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), and central retinal thickness (CRT). Statistical analyses were performed using Student's t-test and Pearson's correlation coefficient. Results: The RNFL was significantly thinner in KC eyes after PKP compared to control eyes (p < 0.001), and the CRT was significantly thicker in KC eyes after PKP compared to control eyes (p = 0.003). However, the GCC was similar across the groups (p = 0.0885). Additionally, RPCs inside the disc were significantly reduced in KC eyes after PKP compared to control eyes (p < 0.0001). A significant positive correlation was found between RPC whole vessel density and RNFL thickness as measured via angio-OCT (r = 0.308, p < 0.0001). Conclusions: This study found that the RPC density inside the disc is significantly reduced in keratoconus patients after penetrating keratoplasty, highlighting RPCs inside the disc as a potential diagnostic tool for further assessment of keratoconus.

Reduced choroidal peripapillary capillaries in thyroid-associated ophthalmopathy with early stage of dysthyroid optic neuropathy.

AIM: To investigate whether the subtle change of choroidal/retinal vessel densities and volumes in thyroid-associated ophthalmopathy (TAO) could be an early sign to detect dysthyroid optic neuropathy (DON). METHODS: This was a retrospective cross-sectional study, and a total of 98 eyes from 50 subjects were enrolled under certain criteria. Thirty-four eyes of normal controls and 64 eyes of TAO, including 39 eyes of DON and 25 eyes of TAO without DON, underwent optical coherence tomography angiography (OCTA) scanning. All the tested parameters of OCTA scanning including choroid radial peripapillary capillaries (RPC), retinal nerve fiber layer (RNFL), and macular ganglion cell complex (GCC) were compared among groups, and the correlation between OCTA parameters and visual function parameters was also investigated. RESULTS: Whole choroidal RPC was significantly reduced in DON (48.24%±0.4978%) compared to normal (50.33%±0.3173%) and TAO without DON (49.16%±0.5463%; P=0.0041). The reduction of whole choroidal RPC was also correlated with visual field (VF) defect in DON (r=0.5422, n=39). Although vision acuity and VF were improved in all the patients with DON after being treated with medical and surgical decompression, the reduction of RPC density were not reversed. CONCLUSION: There is a notable reduction in choroidal RPC in DON, which is correlated with VF defect. The reduction of RPC density could not be reversed immediately by medical and surgical decompression even when vision and VF were improved. These findings suggest that choroidal RPC could be a useful parameter to diagnose and monitor early stage of DON.

Age and signal strength-related changes in vessel density in the choroid and the retina: an OCT angiography study of the macula and optic disc.

PURPOSE: To investigate the effects of ageing and signal strength index (SSI) on vessel density (VD) measurements of the radial peripapillary capillaries (RPC) in the optic disc, the retinal superficial (SCP) and deep (DCP) capillary plexi and the choriocapillaris (CC) of the macular area using optical coherence tomography angiography (OCT-A) imaging. METHODS: This cross-sectional study included 138 eyes from 77 healthy participants. High-definition (HD) disc Angio scan (4.5X4.5 mm) and HD Angio retina scan (6X6 mm) were acquired. Whole image (WI) VDs, inside disc (ID) VD and global and hemifield peripapillary RPC VDs were evaluated from the Angio Disc scans. Global and hemifield VD for the SCP, DCP and CC slab in the macula area were also recorded across different age groups. RESULTS: Mean age was 48.2 ± 15.0 years (range 25-82 years). Signal strength index (SSI) was 71.6 ± 7.6 in the macula and 74.6 ± 9.2 in the disc OCT-A image. VD for both SCP and DCP decreased by 0.084% and 0.188%/year (both p < 0.001). WI VD and ID VD also decreased by 0.037%/year (p = 0.005) and 0.092%/year (p < 0.001). Peripapillary RPC VD did not change with age or SSI. The effect of SSI was significant in SCP, DCP, WI RPC, ID RPC and CC VD. In the generalized estimating equation model testing for both SSI and age, SSI remained significant against SCP, DCP and ID RPC. CONCLUSION: With ageing, a decrease in VD in the SCP, DCP, WI and ID RPC, as well as in SSI, is seen. SSI and age are associated with VD changes, but only SSI is the significant variable that explains the variation in the retina microvasculature in the macula and the optic disc in multivariate analysis. In the CC, a larger SSI was associated with a lower VD. These findings underscore the importance of controlling for SSI in future studies using OCT-A.

Primary visual cortex of the brain is associated with optic nerve head changes in neuromyelitis optica spectrum disorders.

OBJECTIVE: To explore the association between the primary visual cortex in the brain and optic nerve head changes, ONH, (structural thickness and microvascular changes) in neuromyelitis optica spectrum disorder (NMOSD). METHODS: Nineteen patients who were aquaporin-4 (AQP-4) seropositive NMOSD patients and twenty-two healthy controls (HC) were enrolled for this cross-sectional study. Optical coherence tomographic angiography (OCT-A) was used to image and measure the capillaries density (RPC, radial peripapillary capillaries) and structural thickness (pRNFL, peripapillary retinal nerve fiber layer) around the optic nerve head. A resting-state functional magnetic resonance imaging was used to image and evaluate the gray matter volume (GMV) and functional connectivity (FC) the brain of each participant. We assessed the primary visual cortex (lingual gyrus, calcarine sulcus and thalamus) of the brain. RESULTS: Changes in RPC density showed a significant association (P < 0.05) with FC of the right lingual gyrus, bilateral calcarine gyrus and left thalamus respectively. pRNFL thickness showed significant association with FC of the right lingual gyrus (Rho = 0.374, P = 0.016), right calcarine gyrus (Rho = 0.355, P = 0.023) and left thalamus (Rho = 0.376, P = 0.015) respectively. CONCLUSIONS: Visual impairment, structural and microvascular changes around optic nerve head is associated with the functional visual networks in NMOSD. Our report suggests that structural and microvascular changes around the ONH reflect the changes in the primary visual cortex of the brain.

Assessment of Perfused Peripapillary Capillaries and Peripapillary Capillary Density Maps in Glaucoma Patients.

INTRODUCTION: Monitoring and diagnosing glaucoma until 2017 included funduscopy, IOP measurements, gonioscopy, pachymetry, as well as visual field tests, optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A). Radial peripapillary capillaries (RPC) can be observed by fluorescein angiography, as well as histologically - superficial and deep capillary layer. AIM: To correlate density of radial peripapillary capillary network (RPC) and retinal nerve fiber layer (RNFL) thickness in eight peripapillary segments in patients with a primary open angle glaucoma (POAG) which have the disease under 10 years of duration, over 10 years of duration and in a group of healthy patients. METHODS: This is a cross-sectional review which included three groups of patients: POAG patients under 10 years of disease duration, over 10 years of disease duration and control group of patients. The study is performed on the commercial optical coherence tomography angiography system (AngioVue, Avanti RTVue-XR, Optovue, CA). Sectoral RPC density values, RPC maps and RNFL thickness were analyzed in three groups of patients, data was compared and correlation between parameters was examined. RESULTS: Mean RPC Density values in both superior segments (S1, S2) were significantly lower in patients with glaucoma over 10 years of disease duration compared to patients with glaucoma under 10 years of disease duration (p<0.05). Statistically significant positive correlation was established between RNFL thickness and RPC density in all eight peripapillary segments. CONCLUSION: Analysis of radial peripapillary capillary network density on optical coherence tomography angiography may provide an earliest functional sign of progressive optic nerve disease and new insights into the pathophysiology of glaucomatous damage.

Vascular density of optic nerve head in diabetic retinopathy using optical coherence tomography angiography.

PURPOSE: To measure optic nerve head (ONH) blood perfusion using optical coherence tomography angiography (OCTA) at various stages of diabetic retinopathy (DR). METHODS: One hundred seventy six eyes of 94 patients included in this retrospective single-centre cross-sectional study. The subjects were studied in normal, no diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) and proliferative retinopathy (PDR) groups. The eyes were subjected to AngioDisc ONH imaging using OCTA for papillary (Disc) and peripapillary (RPC) vascular density (VD) evaluation. RESULTS: The mean age of the participants was 56.08 ± 8.87 years and 34 (36.2 percent) were male. With increased DR severity, a statistically significant decrease in peripapillary VD was found. The study showed that only VD of the whole RPC (W-RPC) could be a valid biomarker in the staging assessment. VD of RPC, in all subsections, was considerably different from normal cases in the PDR group. Visual acuity was correlated with whole image ONH VD. The duration of DM, FBS, hyperlipidemia and DME had no effect on the ONH perfusion. CONCLUSIONS: The study showed that only the W-RPC VD could be a reasonable marker in the staging assessment. VDs assessed by OCTA can be useful for assessing and tracking early ONH changes in DR patients.

Purtscher-like retinopathy associated with cerebro- or cardiovascular surgery.

PURPOSE: To report the findings in five patients of Purtscher-like retinopathy that developed after cerebro- or cardiovascular surgeries. OBSERVATIONS: Three women and two men with a mean age of 56.6 years were studied. They had had cerebro- or cardiovascular disease that was treated by major vascular surgery. Postoperatively, all of the patients developed multiple patches of retinal whitening in the area corresponding to the radial peripapillary capillaries in the posterior pole of the eye uni- or bilaterally. In two patients, the optic nerve head was involved which affected their vision severely. Hematological examinations showed hypercoagulable state after the surgeries. The retinal pathologies abated with time. CONCLUSIONS AND IMPORTANCE: These results indicate that major cardio- or cerebrovascular surgeries can cause Purtscher-like retinopathy. The hypercoagulable state and specific structures of the radial peripapillary capillaries may play a role in pathogenesis of this disease.

Correlation Between Ischemic Retinal Accidents and Radial Peripapillary Capillaries in the Optic Nerve Using Optical Coherence Tomographic Angiography: Observations in 6 Patients.

BACKGROUND: Perfusion of the optic nerve has been widely studied using fluorescein angiography (FAG), which is currently regarded as the criterion standard. However, FAG has adverse effects associated with intravenous contrast administration and is limited in its capacity to characterize and stratify the different vascular layers of the optic nerve and retina. The use of new imaging techniques, such as optical coherence tomographic angiography (Angio-OCT), is therefore important. AIM: A qualitative description is made of the vascular layers of the optic nerve and of how vascular events affect radial peripapillary capillaries (RPC). Two patients with central retinal artery occlusion (CRAO), 1 with arteritic anterior ischemic optic neuropathy (AAION), and 3 healthy subjects were studied. RESULTS: The Angio-OCT imaging afforded better visualization of the depth of the RPC and rest of the vascular layers of the retina compared with FAG. Optic nerve surface perfusion was affected in AAION and proved normal in CRAO. CONCLUSIONS: Our results indicate that perfusion of the papilla and RPC mainly arises from the papillary plexus that depends on the posterior ciliary artery.