Analysis of foveal avascular zone by using spectral-domain optical coherence tomography angiography in healthy Indian eyes.

PURPOSE: To analyze FAZ superficial (s) and deep (d) area and dimensions by using spectral-domain optical coherence tomography angiography (OCTA) in healthy eyes and to assess effect of age, gender, axial length (AL), central foveal thickness (CFT), and central choroidal thickness (CCT) on FAZ. We aimed to study FAZ dimensions with OCTA in healthy Indian eyes with the purpose of creating a normative database. SETTINGS AND DESIGN: Observational cross-sectional study. METHODS: In total, 200 healthy eyes in the age group of 20-60 years having best corrected visual acuity better than 6/12 (Snellen's) with no systemic illness/intraocular surgery were included. FAZ parameters were calculated using OCTA, and the same was evaluated for any correlation with different ocular parameters mentioned above. The data were reported as frequencies/percentages and mean ± SD. The association between quantitative variables was evaluated using Pearson's correlation coefficient. RESULTS: The dFAZ area (0.56 ± 0.12 mm 2 ) was larger than the sFAZ area (0.42 ± 0.13 mm 2 ). Females had larger FAZ than males. AL and CFT had a negative correlation, whereas CCT had a positive correlation with FAZ. Age did not influence FAZ. sFAZ and dFAZ varied significantly in healthy eyes. CONCLUSION: FAZ parameters calculated using OCTA in healthy Indian eyes suggested that the area and dimensions in both SCP and DCP are larger in individuals from the Indian subcontinent when compared to other parts of the world. FAZ area and dimensions, when compared to previous studies, were variable. Thus, there is a need to establish normative data for ethnicity for proper interpretation of FAZ using OCTA.

Retinal microvascular changes in unilateral functional amblyopia detected by oct-angiography and follow-up during treatment.

OBJECTIVE: To evaluate the macular microvascular changes using optical coherence tomographic angiography (OCT-A) in children with unilateral amblyopia and their reversibility during treatment. METHODS: Patients with unilateral strabismic or anisometropic amblyopia or residual amblyopia from early congenital cataract surgery, examined between October 2019 and March 2021, were included. Vessel density and perfusion density in the superficial capillary plexus and area, perimeter and circularity of the foveal avascular zone (FAZ) were analysed using OCT-A in amblyopic eyes, contralateral eyes and control group healthy eyes. Correlation analyses between the microvascular parameters and the visual acuity were performed. In a pilot study on a few patients from the amblyopic cohort, longitudinal follow-up during treatment was also performed. RESULTS: A total of 128 eyes of 64 patients were included: 32 amblyopic eyes compared with 32 contralateral eyes and 64 control eyes. Vessel density and perfusion density in the superficial capillary plexus were significantly lower in amblyopic eyes compared to control eyes in 6 × 6 mm (p < 0.02) and 3 × 3 mm (p < 0.01) scans. Correlation analyses showed a linear decrease in vessel density and perfusion density with decreasing visual acuity. The microvascular changes observed were reversible with the occlusion treatment of amblyopia (p < 0.001). CONCLUSIONS: The study found a decrease in vessel density and perfusion density in the macula of children with unilateral functional amblyopia. These microvascular changes were correlated with visual acuity and appeared to be reversible with treatment of amblyopia. On the whole, OCT-A appears to be a relevant complementary examination when it comes to diagnosing and monitoring functional amblyopia.

Evaluation of Automated Measurement of Macular Ischemic Changes in Retinal Vein Occlusion With Optical Coherence Tomography Angiography.

OBJECTIVE: The foveal avascular zone (FAZ) is altered in patients with retinal vein occlusion (RVO) and correlates inversely with visual acuity. Optical coherence tomography angiography (OCTA) is an imaging tool to visualize FAZ safely and easily. Automated measurements can facilitate interpretation of OCTA images. In this comparative cross-sectional study, we compare the results of manual measurement of the FAZ with automated measurement by built-in application (Metrix). METHODS: The study included patients with RVO who underwent OCTA. Manual measurement was compared with automated evaluation by Metrix in 3 mm x 3 mm and 6 mm x 6 mm scan sizes and correlations of the circularity, circumference, and size of the FAZ were calculated. RESULTS: Forty-seven eyes were included in the study. A reliable measurement result in both Metrix 3 mm x 3 mm and 6 mm x 6 mm was found in only 25 of 47 eyes. The mean FAZ in these eyes by manual measurement was 0.50 mm2 compared with 0.20 mm2 and 0.24 mm2, respectively, by automated measurement. A statistically significant inverse correlation was found in both the automated 3 mm x 3 mm and 6 mm x 6 mm measurements for FAZ circumference with FAZ circularity but not FAZ area. CONCLUSION: The two automated measurements showed no significant bias regarding the size of the FAZ, but the plausibility of the data should be checked on a case-by-case basis. The manual measurements were higher, indicating limited agreement of manual and automated measurements. The information on circularity can point to ischemic maculopathy early in the course of the disease. [Ophthalmic Surg Lasers Imaging Retina 2023;54:462-469.].

Morphologic analysis of the foveal avascular zone for prediction of postoperative visual acuity in advanced idiopathic epiretinal membrane.

To investigate the preoperative morphology of the foveal avascular zone (FAZ) for prediction of the postoperative visual acuity in advanced idiopathic epiretinal membrane (ERM). 28 patients (28 eyes) with unilateral idiopathic ERM who underwent pars plana vitrectomy with internal limiting membrane peeling were included. Superficial FAZ was measured preoperatively in both eyes using optical coherence tomography angiography. Area, perimeter, and circularity of FAZ were achieved, and the differences between the ERM eyes and the contralateral eyes were evaluated to analyze the degree of FAZ distortion in diseased eyes. The best-corrected visual acuity (BCVA) and central foveal thickness (CFT) were measured at baseline and more than 6 months after surgery. The correlations of the preoperative FAZ with BCVA and CFT were assessed. The FAZ in the eyes with ERM was significantly reduced, and the BCVA was significantly correlated with the FAZ area (FAZa) (P = 0.001) and the FAZ perimeter (FAZp) (P < 0.001) before surgery. LogMAR BCVA and CFT were significantly improved from 0.550 ± 0.221 to 0.354 ± 0.229 (P = 0.008), and from 524.393 ± 93.575 µm to 400.071 ± 75.979 µm (P < 0.001) after surgery. The preoperative FAZa and FAZp were significantly associated with letter score gain (P < 0.001, P < 0.001) and the postoperative final BCVA (P = 0.026, P = 0.006). The preoperative FAZp had correlation with ratio of postoperative to preoperative CFT (P = 0.016). The preoperative FAZp is a predictor of visual acuity and morphological prognosis after surgery in advanced idiopathic ERM.

Optical coherence tomography angiography parameters after cataract surgery.

PURPOSE: To evaluate the changes in macular blood flow after cataract surgery through optical coherence tomography angiography (OCT-A). METHODS: In this prospective case series, 50 patients who underwent uncomplicated cataract surgery by the resident were included. OCT-A images and complete ocular examinations were performed at baseline, 1 and 3 months postoperatively. The changes in OCT-A parameters including foveal avascular zone (FAZ) area, vessel density (VD) of superficial and deep plexus, and central macular thickness were assessed before and after surgery. Cataract grading, intraocular inflammation, and duration of surgery were analyzed. RESULTS: FAZ was significantly reduced from 0.36 ± 0.13 mm2 at baseline to 0.32 ± 0.12 mm2 at month 1 (P < 0.001) and this reduction continued until month 3. In the superficial layer, vessel density of the fovea, parafovea, and whole image significantly increased from 13.9 ± 6.8, 43.7 ± 4.7, and 43.2 ± 4.4 at baseline to 18.4 ± 7.9, 45.7 ± 4.9, and 44.9 ± 4.5 at month 1. The increase in the vessel density of the deep layer was similar to the superficial layer. Accordingly, CMT at the fovea was significantly increased from 240.5 ± 21.99 µm at baseline to 253.1 ± 23.2 microns at month 1 (P < 0.001) and the increase significantly continued and reached 259.5 ± 22.6 µm at month 3 (P < 0.001). Accordingly, the FAZ area significantly reduced one month postoperatively. In regression analysis, CMT changes positively correlated with cataract grading. FAZ area negatively correlated with intraocular inflammation on the first postoperative day. CONCLUSION: The present study shows that CMT and vessel density of the macula significantly increase after uncomplicated cataract surgery, while the FAZ area reduces. Postoperative inflammation could be the possible explanation for the findings of this study.

RHOMBUS DEFORMATION OF RETINAL LATERAL DISPLACEMENT AFTER EPIRETINAL MEMBRANE REMOVAL REVEALED BY DIFFEOMORPHIC IMAGE REGISTRATION.

PURPOSE: To establish an analysis method using diffeomorphic image registration and evaluate microvascular displacement through epiretinal membrane (ERM) removal. METHODS: Medical records of eyes that underwent vitreous surgery for ERM were reviewed. Postoperative optical coherence tomography angiography (OCTA) images were converted to the corresponding preoperative images according to a configured algorithm using diffeomorphism. RESULTS: Thirty-seven eyes with ERM were examined. Measured changes in the foveal avascular zone (FAZ) area showed a significant negative correlation with central foveal thickness (CFT). The average amplitude of microvascular displacement calculated for each pixel was 69 ± 27 µ m in the nasal area, which was relatively smaller than that in other areas. The vector map, which included both the amplitude and the vector of microvasculature displacement, showed a unique vector flow pattern called the rhombus deformation sign in 17 eyes. Eyes with this deformation sign showed less surgery-induced changes in the FAZ area and CFT and a milder ERM stage than those without this sign. CONCLUSION: The authors calculated and visualized microvascular displacement using diffeomorphism. The authors found a unique pattern (rhombus deformation) of retinal lateral displacement through ERM removal, which was significantly associated with the severity of ERM.

Changes in retinal vessel and retinal layer thickness after cross-linking in keratoconus via swept-source OCT angiography.

PURPOSE: To analyze the postoperative foveal avascular zone (FAZ) area, superficial capillary plexus (SCP), deep capillary plexus (DCP) vascular densities (VD), and retinal layers after cross-linking (CXL) for keratoconus treatment. METHODS: Twenty-seven eyes with cross-linking treatment for keratoconus were included in the study. Foveal avascular zone (FAZ) area, SCP VD, DCP VD, and retinal layers were evaluated by using optical coherence tomography angiography (OCTA). OCTA measurements were made at preoperative, first week, and first and sixth months after the surgery. In addition, corneal topography measurements were also made. RESULTS: Although there was a decrease in corneal thickness in the follow-up of the patients, there was no significant difference in axial length and anterior chamber depth. There was no significant difference in full retinal thickness in the foveal and parafoveal areas. While there was a significant increase in retinal nerve fiber layer (RNFL) thickness in the foveal area (p = 0.032, p = 0.015, p = 0.017; preoperative values compared to first week, first month, and sixth month respectively), there was a decrease in ganglion cell layer (GCL) thickness in the parafoveal area in the postoperative sixth month (p = 0.028). There was no difference in FAZ measurements. In the parafoveal area, a decrease was observed in SCP VD in the sixth-month control (p = 0.019). There was a significant increase in DCP VD in the foveal area (p = 0.008, p = 0.043, p = 0.040). The preoperative mean CDVA (corrected distance visual acuity) was 0.37 ± 0.16 logMAR and postoperative sixth month mean CDVA was 0.39 ± 0.15. There was no significant difference in visual acuity (p = 0.71). CONCLUSION: Keratoconus patients successfully treated with CXL had significant changes in retinal layers and vessel density in the superficial and deep retinal plexus.

Effects of smoking on the retina of patients with dry age-related macular degeneration by optical coherence tomography angiography.

BACKGROUND: The macula of the retina is analysed using optical coherence tomography angiography (OCTA) to provide clinical basis and explain the mechanism of smoking as a risk factor in dry age-related macular degeneration (AMD). METHODS: This cross-sectional study included 49 normal control nonsmokers, 12 normal control smokers, 38 dry AMD nonsmokers and 35 dry AMD smokers. The foveal avascular zone (FAZ), foveal density (FD) in a 300 µm region around FAZ, vessel densities of the superficial (SCP) and deep (DCP) capillary plexuses and central fovea retinal thickness (FRT) were compared using OCTA. The bivariate correlation analysis was used to evaluate the effect of pack-year history on retina-related indices. RESULTS: The vessel densities of whole, foveal and parafoveal of SCP and whole and parafoveal of DCP in the control nonsmoking group were all significantly higher than those in the dry AMD nonsmoking group (all P < 0.05), whereas the whole vessel density of SCP in the normal smoking group was higher than that in the dry AMD smoking group (P = 0.04). The thickness values of the inner and full-layer FRT in the normal nonsmoking group were significantly thicker than those in the dry AMD nonsmoking group (all P < 0.01). The pack-year history was negatively correlated with the parafoveal vessel density of DCP (r = - 0.224, P < 0.01). CONCLUSIONS: FD, SCP, DCP and FRT are sensitive indices for the detection of early and intermediate dry AMD. DCP is a sensitive indicator that reflects the effects of smoking on the retina. Considerable changes are observed in retinal vessels, suggesting that dry AMD may affect the retinal tissue to a certain extent.

Macular Morphologic and Microvascular Analysis in Pseudophakic Children with Previous Pediatric Cataract Using Optical Coherence Tomography Angiography.

INTRODUCTION: The macular morphologic and microvascular changes in children with pseudophakia after pediatric cataract surgery remain unknown. The aim of this study was to analyze macular morphologic and microvascular remodeling in children with pseudophakia after pediatric cataract surgery using optical coherence tomography angiography (OCTA). METHODS: Consecutive cases between December 1, 2018, and November 31, 2020 were recruited. Sixty-one participants (31 pseudophakic children and 30 healthy controls) met the inclusion criteria and were included for final analysis. OCTA was used to measure macular vascular density, the foveal avascular zone (FAZ), and macular thickness. The parameters were compared between pseudophakic and healthy eyes using binary logistic regression, with adjustment for the effect of refractive error, age, and axial length. RESULTS: Compared with normal eyes, a significantly reduced area of the FAZ (p = 0.042), increased superficial foveal vascular density (p = 0.033), and increased inner and outer foveal thickness (p = 0.034 and 0.029, respectively) were noted in pseudophakic eyes. The deep parafoveal vascular density was generally lower in eyes with cataracts (p ≤ 0.044). The inner foveal thickness was positively correlated with the superficial foveal vascular density (r = 0.889, p < 0.001) and negatively correlated with the area of the FAZ (r = -0.903, p < 0.001). The outer foveal thickness was positively correlated with the deep foveal vascular density (r = 0.399, p = 0.002). CONCLUSIONS: Morphological and microvascular remodeling in children with previous pediatric cataract indicates foveal underdevelopment. The underlying mechanism requires further investigation.

Evaluation of subclinical ocular involvement in patients with deficiency of adenosine deaminase 2 (DADA2).

PURPOSE: To evaluate changes in the peripapillary, macular, and choroidal microvasculature in the eyes of patients with deficiency of adenosine deaminase 2 (DADA2) and no clinical signs of ocular involvement. METHODS: The study included 12 eyes of 12 patients with DADA2 and 24 eyes of 24 healthy subjects. The foveal avascular zone (FAZ), macular vessel densities (VDs) in the superficial and deep retinal capillary plexuses, peripapillary VDs, and choroidal thickness were evaluated by optical coherence tomography angiography (OCTA). Measurements were compared between DADA2 patients and healthy controls. RESULTS: The median age was 17 (8-25) years in DADA2 patients and 17.5 (7-23) years in control group at the OCTA visit (p = 0.934). FAZ area did not differ between the groups (p = 0.224). In the superficial capillary plexus, whole-image, foveal, and parafoveal VD values were slightly lower in DADA2 patients than in controls (p = 0.054, p = 0.052, p = 0.117). In the deep capillary plexus, whole-image and parafoveal VD values were significantly lower in DADA2 patients than controls (p = 0.010, p = 0.001). VD in the radial peripapillary capillary plexus was also lower in DADA2 patients, with significantly lower peripapillary VD (p = 0.002). Subfoveal choroidal thickness was significantly higher in patients with DADA2 (p < 0.001). CONCLUSIONS: This OCTA study demonstrates that both retinal and choroidal involvement may occur in DADA2 patients before the emergence of evident clinical findings.

Functional and Structural Findings in Infants Treated for Retinopathy of Prematurity Using Optical Coherence Tomography Angiography.

BACKGROUND AND OBJECTIVE: To assess the foveal microvascular structure of children with retinopathy of prematurity (ROP) treated with diode laser photocoagulation using optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: OCTA was performed at a tertiary medical center in 17 children (27 eyes) aged 4 to 16 years with a history of diode laser photocoagulation treated ROP. OCTA parameters were compared with those of 12 healthy age-matched controls (23 eyes) attending the orthoptics clinic and correlated with clinical factors. RESULTS: Compared with controls, the ROP group had a smaller foveal avascular zone area (P < .001), lower deep vascular plexus density (P < .001), lower flow density (P = .025), and greater central macular thickness (P < .001). High intraventricular hemorrhage grade correlated with smaller foveal avascular zone area (P = .008) and greater inner macular thickness (P = .047). There was no impact of gestational age, birth weight, or refractive status. CONCLUSION: OCTA can identify significant quantifiable long-term macular microvascular and structural changes in this patient population. [Ophthalmic Surg Lasers Imaging Retina. 2022;53(4):194-201.].

Analysis of optical coherence tomography angiographic findings of prematurely born children and its relationship with macular edema of prematurity.

PURPOSE: To compare foveal avascular zone (FAZ) area, foveal vascular density (VD), and foveal thickness in pre- and full-term children and to evaluate their relationship with cystoid macular edema (CME) in the prematurity period using spectral domain optical coherence tomography angiography (SD-OCTA). METHODS: OCTA imaging was performed at 4-6 years of age in 90 eyes of 45 prematurely born children and 50 eyes of 25 term children. Subjects were divided into three groups: prematurely born with CME (group 1); prematurely born without CME (group 2); healthy, term children (group 3). Imaging results in the three groups were compared. RESULTS: FAZ area was significantly larger in group 3 than in groups 1 and 2 (P < 0.001 [ANOVA]). FAZ area was found to be correlated with birth weight (r = 0.511; P < 0.001) and gestational age (r = 0.532; P < 0.001). No significant relationship was found between history of CME and FAZ area. CONCLUSIONS: In our study cohort, FAZ area was smaller in prematurely born children and was correlated with older gestational age and higher birth weight. CME in the neonatal period did not seem to affect retinal microvascular development in premature infants.

Retinal microvasculature features in patients with Behcet's disease: a systematic review and meta-analysis.

This meta-analysis aimed to analyze retinal microvasculature features in eyes with Behçet's disease (BD) using optical coherence tomography angiography (OCTA). Electronic databases, including PubMed, Web of Science, Embase, and Cochrane Library, were comprehensively searched for published studies comparing retinal microvasculature characteristics between eyes with BD and controls. Continuous variables were calculated using the mean difference (MD) with 95% confidence interval (CI). Review Manager software (version 5.30) was used to conduct statistical analysis. A total of 13 eligible studies involving 599 eyes with BD and 622 control eyes were included in the meta-analysis. The pooled results showed that the macular whole enface superficial and deep vessel density (VD) values measured by OCTA were significantly lower in eyes with BD than in control eyes (superficial VD: MD = - 3.05, P < 0.00001; deep VD: MD = - 4.05, P = 0.0004). The foveal superficial and deep VD values were also significantly lower in the BD group than in the control group (superficial VD: MD = - 1.50, P = 0.009; deep VD: MD = - 4.25, - = 0.03). Similarly, the analysis revealed a significant reduction in the parafoveal superficial and deep VD in eyes with BD than in control eyes (superficial VD: MD = - 3.68, P < 0.00001; deep VD: MD = - 4.95, P = 0.0007). In addition, the superficial and deep foveal avascular zones (FAZs) were significantly larger in patients with BD than in controls (superficial FAZ: MD = 0.06, P = 0.02; deep FAZ: MD = 0.12, P = 0.03). The present meta-analysis found that macular whole enface VD, foveal VD, and parafoveal VD were lower in eyes with BD, and the FAZ was larger in patients with BD. The findings suggest that OCTA can assist clinicians in diagnosing and monitoring the status of patients with BD.

OCT angiography measured changes in the foveal avascular zone area after glaucoma surgery.

BACKGROUND/AIMS: To evaluate quantitative changes in the foveal avascular zone (FAZ) area after glaucoma surgery using swept-source optical coherence tomography angiography (SS-OCTA). METHODS: Fifty-four consecutive patients with primary open-angle glaucoma (POAG) who met the inclusion criteria and underwent unilateral glaucoma surgery to reduce intraocular pressure (IOP) between April 2018 and July 2019.Eyes underwent IOP-lowering glaucoma surgery and their fellow (non-surgical) eyes were included. OCTA of the macula was performed in both eyes before glaucoma surgery and 3 months postoperatively. Two blinded examiners reviewed the image quality. Within- and between-group comparisons of the FAZ area and correlation of the FAZ area with age, IOP, central sensitivity and clinical variables. RESULTS: The mean (±SD) age was 66.7±11.3 years. After surgery, the IOP and FAZ area significantly decreased from 22.1±9.5 mmHg to 10.3±3.5 mmHg and from 0.485±0.193 mm2 to 0.446±0.174 mm2, respectively (both p<0.001). Conversely, in the non-surgery group, the preoperative and postoperative mean FAZ areas (0.398±0.119 mm2 and 0.396±0.110 mm2, respectively) did not significantly differ (p=0.469). Change in the FAZ area significantly correlated with the preoperative FAZ area, preoperative foveal sensitivity and change in IOP (all p<0.05). CONCLUSIONS: The FAZ area is decreased with IOP-lowering surgery in patients with POAG, and change in the FAZ area was significantly correlated with both preoperative foveal sensitivity and change in IOP.

Effect of Foveal Pit Restoration in Foveal Avascular Zone after Surgery for Idiopathic Epiretinal Membrane.

PURPOSE: To investigate the relationship between ophthalmic parameters-including optical coherence tomography (OCT) and OCT angiography findings-and foveal pit restoration in eyes that had undergone vitrectomy for idiopathic epiretinal membrane (iERM) removal. METHODS: This study retrospectively analyzed data of patients who underwent pars planar vitrectomy for the removal of epirentinal membrane. Only eyes with iERM above stage 2 with a follow-up over 6 months were included. Baseline data and changes in ophthalmic parameters were analyzed from 3 months before to 12 months after surgery. Additionally, we stratified iERM patients into two groups (foveal pit restoration and no restoration group). Longitudinal comparison analyses between the two groups were done in best-corrected visual acuity (BCVA), central foveal thickness (CFT) and foveal avascular zone (FAZ) areas measurements using swept-source OCT and OCT angiography. RESULTS: Forty-three patients with a mean age of 75 ± 5 years were enrolled. After surgery, BCVA, FAZ, and CFT showed improvements over time (all p < 0.002). Thirty-one patients were designated into the foveal pit restoration (R) group and 12 patients into the no restoration (NR) group. Differences in BCVA and FAZ area in both groups existed up to 6 months. However, BCVA improved and FAZ expanded (R, 0.20 ± 0.05 vs. NR, 0.18 ± 0.04) in both groups showing no statistical difference 12 months postsurgery. The CFT decreased in both groups, but the R group was thinner at every point compared to the NR group (all p < 0.05). CONCLUSIONS: The removal of epirentinal membrane in pars planar vitrectomy significantly improves BCVA, decreases the CFT and expands the FAZ. Foveal pit restoration improves BCVA, CFT, and FAZ area possibly at a faster rate in the early months but long-term improvements could be achieved regardless of the status of foveal pit restoration.

Association between retinal vessel density and postoperative time after primary repair of rhegmatogenous retinal detachment.

The study aimed at a quantitative evaluation of macular vasculature after primary repair of rhegmatogenous retinal detachment (RRD) in correlation with the elapsed postoperative time. Optical coherence tomography angiography (OCT-A) was performed in 66 eyes of 33 patients in a retrospective case-control study: superficial and deep retinal vessel density (VD) of the whole image, fovea, parafovea, non-flow area, and foveal avascular zone (FAZ) were measured. Data of eyes with RRD were compared to the healthy fellow eyes in 3 groups according to the elapsed time after surgery: RD1: 6-12 months (n = 10), RD2: 1-2 years (n = 10), and RD3: 2-10 years (n = 13). In RD1 VD was significantly lower in the superficial parafoveal, deep parafoveal, and deep whole area compared to the fellow eyes. In RD3 VD was significantly lower in the superficial fovea, parafovea, whole image, and deep fovea, the non-flow area was significantly enlarged. OCT-A demonstrated a significant reduction in the superficial and deep regions of the macular vasculature after the repair of RRD. The deep area is more affected in the early postoperative period and the superficial region and the extent of the non-flow area are more involved after a longer postoperative time.

Anatomic-Functional Correlates in Lesions of Retinal Vein Occlusion.

Purpose: To evaluate anatomic-functional associations at sites of retinal lesions in retinal vein occlusion (RVO). Methods: This pilot, prospective, observational study was conducted at the Northern Ireland Clinical Research Facility (NICRF) of Queen's University and the Belfast Health and Social Care Trust, Northern Ireland, between August 1, 2018, and September 30, 2019. The study included 10 treatment-naïve patients with RVO (10 RVO eyes and 10 fellow eyes). There were 81 points/sites assessed for each eye at baseline; six patients were re-assessed 6 months after anti-vascular endothelial growth factor therapy at the same locations. We investigated associations between retinal sensitivity and presence of structural RVO lesions, including retinal ischemia, hemorrhages, intraretinal fluid (IRF) and subretinal fluid outside the foveal/parafoveal regions. Comparisons were made between RVO eyes and fellow eyes at baseline, and between RVO eyes at baseline and at 6 months after treatment. Regression models were used to investigate anatomic-functional associations. Results: At baseline, strong associations were found between reduced retinal sensitivity and presence of ischemia (estimate = -2.08 dB; P < 0.001), intraretinal fluid (estimate = -7.82 dB; P < 0.001), and subretinal fluid (estimate = -8.66 dB; P < 0.001). Resolution of subretinal fluid but not intraretinal fluid was associated with improved function (estimate = 2.40 dB [P = 0.022]; estimate = 1.16 dB [P = 0.228], respectively). However, reperfusion of ischemic retina, observed in 31 of 486 points (6%) 6 months after anti-vascular endothelial growth factor therapy, was associated with a further decrease in retinal sensitivity (estimate = -2.34 dB; P = 0.035). Conclusions: Retinal sensitivity was decreased at sites of RVO lesions. Decreased function at sites of retinal ischemia did not recover after treatment, even when reperfusion occurred.

Optical coherence tomography angiography findings in patients with ocular and non-ocular Behcet disease / Achados de angiografia por tomografia de coerência óptica em pacientes com doença de Behçet com e sem acometimento ocular

ABSTRACT Purposes: To evaluate the optical coherence tomography angiography findings in patients with Behçet disease with and without ocular involvement. Methods: A total of 40 patients with Behçet disease and 30 healthy controls were enrolled in the study. Retinal vessel density in the superficial capillary plexus and deep capillary plexus, foveal avascular zone area and perimeter, acirculatory index, foveal density, and nonflow area in the superficial retina were automatically measured using the optical coherence tomography angiography software AngioVue and compared between the groups. Results: The mean parafoveal and perifoveal vessel densities in the superficial capillary plexus and deep capillary plexus and foveal density were significantly lower in the eyes with Behçet uveitis compared to the eyes without Behçet uveitis and eyes of the healthy controls. In the eyes with Behçet uveitis, logMAR visual acuity showed a moderate correlation with parafoveal and perifoveal vessel densities and foveal density (r=-0.43, p=0.006; r=-0.62, p<0.001; r=-0.42, p=0.008; respectively). Conclusion: Behçet disease with posterior uveitis was associated with significant perifoveal and parafoveal vascular decrements in the superficial and deep retina.(AU)

RESUMO Objetivo: Avaliar achados de angiografia por tomografia de coerência óptica em pacientes com doença de Behçet com e sem acometimento ocular. Métodos: Foram incluídos 40 pacientes com doença de Behçet e 30 controles saudáveis. A densidade vascular retiniana nos plexos capilares superficial e profundo, a zona avascular foveal, o índice de circularidade, a densidade foveal e a área sem fluxo da retina superficial foram medidos automaticamente, através do software AngioVue para angiografia por tomografia de coerência óptica, e comparados entre os grupos. Resultados: A densidade vascular parafoveal e perifoveal média nos plexos capilares superficial e profundo, bem como a densidade foveal, foram significativamente menores nos olhos com uveíte de Behçet em comparação com os olhos sem uveíte de Behçet e os olhos dos controles saudáveis. Nos olhos com uveíte de Behçet, a acuidade visual logMAR mostrou correlação moderada com a densidade vascular parafoveal e perifoveal e com a densidade foveal (respectivamente, r=-0,43, p=0,006; r=-0,62, p<0,001; e r=-0,42, p = 0,008). Conclusão: A doença de Behçet com uveíte posterior foi associada a decréscimos significativos da vascularização perifoveal e parafoveal na retina superficial e profunda.(AU)

Foveal avascular zone segmentation in optical coherence tomography angiography images using a deep learning approach.

The purpose of this study was to introduce a new deep learning (DL) model for segmentation of the fovea avascular zone (FAZ) in en face optical coherence tomography angiography (OCTA) and compare the results with those of the device's built-in software and manual measurements in healthy subjects and diabetic patients. In this retrospective study, FAZ borders were delineated in the inner retinal slab of 3 × 3 enface OCTA images of 131 eyes of 88 diabetic patients and 32 eyes of 18 healthy subjects. To train a deep convolutional neural network (CNN) model, 126 enface OCTA images (104 eyes with diabetic retinopathy and 22 normal eyes) were used as training/validation dataset. Then, the accuracy of the model was evaluated using a dataset consisting of OCTA images of 10 normal eyes and 27 eyes with diabetic retinopathy. The CNN model was based on Detectron2, an open-source modular object detection library. In addition, automated FAZ measurements were conducted using the device's built-in commercial software, and manual FAZ delineation was performed using ImageJ software. Bland-Altman analysis was used to show 95% limit of agreement (95% LoA) between different methods. The mean dice similarity coefficient of the DL model was 0.94 ± 0.04 in the testing dataset. There was excellent agreement between automated, DL model and manual measurements of FAZ in healthy subjects (95% LoA of - 0.005 to 0.026 mm2 between automated and manual measurement and 0.000 to 0.009 mm2 between DL and manual FAZ area). In diabetic eyes, the agreement between DL and manual measurements was excellent (95% LoA of - 0.063 to 0.095), however, there was a poor agreement between the automated and manual method (95% LoA of - 0.186 to 0.331). The presence of diabetic macular edema and intraretinal cysts at the fovea were associated with erroneous FAZ measurements by the device's built-in software. In conclusion, the DL model showed an excellent accuracy in detection of FAZ border in enfaces OCTA images of both diabetic patients and healthy subjects. The DL and manual measurements outperformed the automated measurements of the built-in software.