Objective To observe the dimensions of the capillary blood vessel arch in central fovea of macula and the foveal avascular area (FAZ), and their relationships with age.Methods Retina in macula of 32 cadavers eyes were isolated . Retinal vessels were immunostained by collagen type IV and examined by confocal laser scanning microscopy. The area and diameter of the FAZ were measured, and the relationship between FAZ and age was analysed. Results The parafoveolar capillary network was observed clearly by confocal laser scanning microscopy. The average area of the FAZ was (0.24±0.13) mm2, and the average diameter was (0.54±0.15) mm. The area and diameter of the FAZ did not show any correlation with age.Conclusions The parafoveolar capillary network could be observed by confocal laser scanning microscopy. The size of the FAZ does not change with age. The dimensions of the parafoveolar capillary network may not be influenced by age. (Chin J Ocul Fundus Dis，2003，19：73-75)
Objective To analyze the correlation of foveal avascular zone (FAZ) size with visual acuity and metamorphopsia in idiopathic macular epiretinal membrane (IMEM) eyes. Methods This is a cross-sectional study, including 43 patients (43 eyes) with IMEM (IMEM group) and 35 health subjects (35 eyes) as control group. The best corrected visual acuity (BCVA) was measured using the international standard visual acuity chart, and the results were converted to the logarithm of the minimum angle of resolution (logMAR) visual acuity. The severity of metamorphopsia was measured using M-charts. The FAZ areas were estimated with optical coherence tomography angiography (OCTA) in both the superficial and deep capillary plexus layers. The central macular thickness (CMT) was assessed with spectral-domain optical coherence tomography. There was no difference of logMAR BCVA and CMT between two groups (Z=−7.379, −7.560; P＜0.001). The differences of FAZ areas between the two groups were analyzed. The correlative analysis was performed to investigate the relationship between FAZ areas and visual acuity as well as metamorphopsia. Results The FAZ area in superficial and deep capillary plexus in IMEM group were smaller than those in control group (t=−30.316, −27.606; P＜0.001). In IMEM group, the mean M-score was 0.41±0.32; the horizontal and vertical M-score were 0.49±0.40 and 0.32±0.29, respectively. The horizontal M-score was higher than vertical M-score with the significant difference (Z=−2.000, P=0.046). In IMEM group, the FAZ area in superficial capillary plexus correlated inversely with metamorphopsia (r=−0.709, P＜0.001); the FAZ area in deep capillary plexus correlated inversely with metamorphopsia and BCVA (r=−0.533, −0.838; P＜0.001). Conclusions The FAZ areas are significantly decreased in IMEM eyes compared with normal eyes. Both superficial and deep FAZ areas are correlated with metamorphopsia, and deep FAZ area is also correlated with BCVA.
ObjectiveTo observe the macular capillary morphology in diabetic patients.MethodsA total of 61 patients (104 eyes) with diabetes mellitus (DM group) and 31 healthy controls (41 eyes) were enrolled in the study. According to the degree of diabetic retinopathy (DR), the DM group was divided into non-DR (NDR) group, non-proliferative DR (NPDR) group, and proliferative DR (PDR) group. There were 13 patients (23 eyes), 21 patients (34 eyes) and 27 patients (47 eyes) in each group, respectively. According to whether there was diabetic macular edema (DME), the DM patients were divided into DME group and non-DME group, each had 20 patients (28 eyes) and 41 patients (76 eyes), respectively. The age (F=2.045) and sex (χ2=2.589) between the control group, the NDR group, the NPDR group and PDR group were not statistically significant (P=0.908, 0.374). The 3 mm × 3 mm region in macula was scanned by optical coherence tomography angiography (OCTA), and the retinal capillary morphological changes of superficial capillary layer (SCL) and deep capillary layer (DCL) were observed. Chi-square test and t test were used to compare data among different groups.ResultsThere was no abnormal change of retinal capillary morphology in control group. Microaneurysms and foveal avascular zone (FAZ) integrity erosion can be found in NDR group. There were microaneurysms, FAZ integrity erosion, vascular tortuosity bending, capillary non-perfusion and venous beading in NPDR and PDR groups. The microaneurysms of DCL were significantly more than that of the SCL (t=4.759, P＜0.001). The eyes with microaneurysms in NDR group, NPDR group, and PDR group showed significant differences (χ2=44.071, P＜0.001), and the eyes with FAZ integrity erosion among these three groups also showed significant differences (χ2=30.759, P＜0.001). Compared with NPDR group and PDR group, there were significant differences in vascular tortuosity bending and capillary non-perfusion (vascular tortuosity bending: OR=0.213, 95%CI 0.070−0.648, P=0.004; capillary non-perfusion: OR=0.073, 95%CI 0.022−0.251, P＜0.001), and there was no significant difference in venous beading (OR=0.415, 95%CI 0.143−1.208, P=0.102). SCL blood flow density in the 4 groups (control, NDR, NPDR and PDR group) was 49.233±1.694, 48.453±2.581, 45.020±4.685 and 40.667±4.516, respectively. While the difference between the control and NDR group was not significant, the differences between other pairs (control vs NPDR/PDR, NDR vs NPDR/PDR, NPDR vs PDR) were significant. The ratio of FAZ integrity erosion and non-perfusion of DME group was significantly higher than those of non-DME group (vascular tortuosity bending: OR=7.719, 95%CI 1.645−36.228, P=0.004; capillary non-perfusion: OR=14.560, 95%CI 3.134−67.646, P＜0.001).ConclusionsOCTA can distinctively detect the abnormal retinal capillary changes of SCL and DCL in diabetic patients. Even in DM patients without diabetic retinopathy, OCTA can detect abnormal blood vessels.
Objective To observe the effect of different macular edema on the area of foveal avascular zone (FAZ) and its correlation in eyes with branch retinal vein occlusion (BRVO). Methods A total of 72 patients (75 eyes) diagnosed with BRVO were included in the study. There were 40 patients males (42 eyes) and 32 females (33 eyes), with the mean age of (56.00±9.96) years. All the eyes were examined by BCVA, intraocular pressure, slit lamp microscope combined with preset lens, fundus color photography and optical coherence tomography angiography (OCTA). BRVO patients were divided into two groups according to the degree of macular edema: group M300 that was CRT ≥300 μm (38 patients, 39 eyes) and group L300 that was CRT＜300 μm (34 patients, 36 eyes). The macular angiography scan protocol covered a 3 mm×3 mm area. The parameters of macular were measured by the built-in measurement software of the system: (1) area of FAZ, perimeter of FAZ (PERIM), avascular index of FAZ (AI), vascular density within a width of 300 μm around the FAZ region (FD-300); (2) central retinal thickness (CRT); (3) vascular density (VD): the superficial central fovea vascular density (SFVD), the deep central fovea vascular density (DFVD), the superficial hemi-macular vascular density (SHVD), the deep hemi-macular vascular density (DHVD). Spearman test was used to test the correlation between FAZ area and other parameters in each group. Results The FAZ area in group M300 and L300 were 0.388±0.166 mm2 and 0.596±0.512 mm2, respectively. The results of Spearman test showed that the FAZ area of group M300 was positively correlated with PERIM and AI (r=0.932, 0.591; P=0.000, 0.000), negatively correlated with SFVD, DFVD and SHVD (r=−0.490, −0.429, −0.339; P=0.002, 0.006, 0.035). But there was no significant negative correlation between FAZ area and FD-300, CRT, DHVD in group M300 (r=−0.129, −0.053, −0.400; P=0.435, 0.749, 0.395). The FAZ area in group L300 was positively correlated with PERIM and AI (r=0.887, 0.633; P=0.000, 0.000), negatively correlated with SFVD, DFVD, SHVD and DHVD (r=−0.413, −0.643, −0.630, −0.370, −0.411; P=0.012, 0.000, 0.000, 0.026, 0.013). But there was no significant positive correlation between FAZ area and FD-300 in group L300 (r=0.093, P=0.590). Conclusion FAZ area varies with the degree of macular edema. The degree of macular edema is higher, the FAZ area is smaller. FAZ area is positively correlated with PERIM and AI significantly, and negatively correlated with SFVD, DFVD and SHVD.
Objective To analyze the correlation between foveal avascular zone (FAZ) size and foveal morphology in patients with idiopathic macular epiretinal membrane (IMEM) using OCT angiography (OCTA). Methods A retrospective case series study contained of 54 eyes of 54 patients affected with IMEM (IEM group) and 50 eyes of 50 normal persons as the control group. The BCVA was measured using the international standard visual acuity chart, and the results were converted to the logMAR visual acuity. The FAZ areas were evaluated with OCTA in both the superficial and deep capillary plexus layers by using 3 mm×3 mm images of the macular. The central macular thickness (CMT), inner retinal layer thickness (IRT), outer retinal layer thickness (ORT), subfoveal choroidal thickness (SFCT), and the status of ellipsoid zone (EZ) were assessed with spectral-domain optical coherence tomography. The differences of FAZ areas between the two groups were analyzed. The correlative analysis was performed to investigate the relationship between areas and foveal morphology. Results Compared with control group, the FAZ area in superficial and deep capillary plexus in the IMEM group were significantly smaller (t=−29.095, −28.743; P＜0.001, ＜0.001); the mean CMT, IRT, ORT and SFCT were significantly thickening in the IMEM group (Z=−8.784, −8.524, −7.709, −7.535; P＜0.001, ＜0.001, ＜0.001, ＜0.001). In the IMEM group, the FAZ area in superficial capillary plexus correlated inversely with the CMT, IRT, and the integrity of EZ (r=−0.464, −0.536, −0.293; P＜0.001, ＜0.001, 0.039), no significant correlation of superficial plexus FAZ areas with ORT and SFCT (r=−0.218, −0.165; P=0.172, 0.157). The FAZ area in deep capillary plexus correlated inversely with the CMT, IRT, and the integrity of EZ (r=−0.306, −0.694, −0.468; P=0.037, ＜0.001, ＜0.001), no significant correlation with ORT and SFCT (r=−0.242, −0.227; P=0.079, 0.094). Conclusions The FAZ areas is significantly decreased in IMEM eyes compared with normal eyes. Both superficial and deep FAZ area are correlated with the CMT, IRT, and the integrity of EZ.
ObjectiveTo observe the changes of foveal avascular zone (FAZ) size before and after surgery in idiopathic macular epiretinal membrane (IMEM) eyes and analyze the correlation of FAZ with metamorphopsia.MethodsA retrospective case series study. From August 2016 to October 2017, 42 eyes of 38 patients affected with IMEM diagnosed in Central Theater Command General Hospital of Chinese People's Liberation Army were enrolled in this study. All the patients underwent a 25G pars plana vitrectomy (PPV) with IMEM removal and ininternal limiting membrane (ILM) peeling. The BCVA was measured using the international standard visual acuity chart, and the results were converted to the logMAR visual acuity. The severity of metamorphopsia was measured using M-charts. The FAZ areas were evaluated with OCT angiography in both the superficial and deep capillary plexus layers. The central macular thickness (CMT) were assessed with spectral-domain OCT before and after surgery. The logMAR BCVA was 0.61±0.21. The M-score was 0.66±0.38. The CMT of fovea was 337.71±57.63 μm. The FAZ areas in superficial and deep capillary plexus were 0.113±0.037 mm2 and 0.202±0.03 mm2, respectively. The differences in BCVA, M-score and FAZ area before and 1, 3, 6, 12 months after surgery were analyzed by ANOVA. The Spearman rank correlation analysis was performed to investigate the relationship between FAZ areas, visual acuity and metamorphopsia.ResultsAt 12 month after surgery, the FAZ areas in superficial and deep capillary plexus were 0.146±0.021 mm2 and 0.240±0.019 mm2, respectively. Compared with baseline, the the FAZ areas in superficial and deep capillary plexus after surgery significantly increased (F=8.484, 14.346; P＜0.001,＜0.001). The postoperative logMAR BCVA 0.47±0.19, M-score 0.12±0.22 and CMT 270.60±33.27 μm were significantly improved compared with baseline (F=5.044, 17.763, 13.545; P=0.001,＜0.001,＜0.001). The preoperative FAZ area in superficial capillary plexus correlated negatively with preoperative M-score (r=－0.816, P＜0.001); the preoperative FAZ area in deep capillary plexus correlated negatively with preoperative BCVA and M-score (r=－0.422, －0.882; P=0.005,＜0.001). The postoperative FAZ area in superficial capillary plexus correlated negatively with preoperative and postoperative M-score (r=－0.791,－0.716; P＜0.001,＜0.001). The postoperative FAZ area in deep capillary plexus correlated negatively with BCVA and preoperative and postoperative M-score (r=－0.343, －0.330, －0.732, －0.694; P=0.026, 0.033,＜0.001,＜0.001).ConclusionsPPV with ILM peeling can effectively restore the FAZ areas in superficial and deep capillary plexus, improve the visual acuity and metamorphopsia in patients with IMEM. Both superficial and deep plexus FAZ areas correlated negatively with metamorphopsia, and deep plexus FAZ area also correlated negatively with BCVA.
ObjectiveTo evaluate the changes in foveal avascular zone (FAZ) size and foveal microstructures in patients with rhegmatogenous retinal detachment (RRD) and to analyze the correlation between FAZ size, foveal microstructure changes and visual outcomes.MethodsA retrospective study. From January 2017 to January 2019, 79 RRD patients (79 eyes) diagnosed in Department of Ophthalmology in Baoding First Central Hospital were included in the study. The patients were divided into macula-off group (51 eyes), macula-on group (28 eyes). The unaffected fellow eyes were used as a control group. The retinas were reattachment in all eyes after first standard 23G PPV combined with silicone oil filling. Before and 3 months after surgery, all patients underwent a comprehensive ophthalmologic examination, including the measurement of BCVA and OCT angiography (OCTA) examination. The BCVA examination was performed using the international standard visual acuity chart, which was converted into logMAR visual acuity. The FAZ areas were evaluated with OCTA in the superficial capillary plexus layers by using 3 mm×3 mm images of the macular. The following postoperative foveal microstructures were evaluated:epiretinal membranes, macular edema, subretinal fluids, integrity of ellipsoidal zone and external limiting membrane. Pearson correlation analysis was used to analyze the correlation between FAZ area and BCVA. The correlation between macular microstructures and BCVA was analyzed by Spearman correlation analysis.ResultsAt 3 months after the removal of silicone oil, the FAZ area in the macula-off group, macula-on group and the control group were 0.447±0.041, 0.409±0.034, 0.335±0.027 mm2, respectively. Compared with the control group, the FAZ area in the macula-off group and macula-on group were enlarged, the difference was statistically significant (F=184.148, P＜0.05). The logMAR BCVA in the macula-off group and macula-on group were 0.800±0.180 and 0.386±0.160, respectively. There was significant difference in ellipsoidal zone rupture between the two groups (χ2=7.577, P=0.006). The results of correlation analysis showed that the area of FAZ and the incidence of ellipsoidal zone fracture after surgery were positively correlated with BCVA after surgery (r=0.329, 0.290; P=0.003, 0.010).ConclusionsThe FAZ area of RRD is enlarged after surgery. FAZ area and ellipsoid zone fracture are positively correlated with BCVA after surgery.
ObjectiveTo observe the correlation between the changes of area foveal avascular zone (FAZ), central foveal thickness (CFT), the thickness of the macular ganglion cell-inner plexiform layer (GCIPL) and the BCVA in type 2 diabetic mellitus patients with different fundus lesions.MethodsA prospective clinical study. Eighty-three eyes of 51 patients with type 2 diabetic mellitus were collected in Shengjing Hospital of China Medical University from January 2018 to January 2019, including 31 males and 20 females. The average age was 53.4±7.8 years. According to the diabetic retinopathy international clinical staging criteria, the patients were divided into the non-diabetic retinopathy (NDR) group with 17 patients (31 eyes), and the non-proliferative diabetic retinopathy (NPDR) group with 34 patients (52 eyes). And 13 control eyes of 8 age- and sex-matched healthy physical examination subjects (control group) were selected in this study. The BCVA examination was performed using the international standard visual acuity chart, which was converted into IogMAR visual acuity. OCT was used to measure the CFT, the mean and the minimum thickness of GCIPL. OCT angiography (OCTA) examination was applied to obtain blood flow density scan images in macular area of 3 mm × 3 mm size. The superficial FAZ area was measured by Photoshop software. The differences of the superficial FAZ area, BCVA, CFT, the mean and the minimum thickness of GCIPL in each group were statistically analyzed, and to explore the correlation between the parameters. Analysis of variance was used to compare measurement data among three groups, and chi-square test was used for the comparison of counting data among three groups. The statistical correlation was evaluated using Pearson’s correlation coefficient.ResultsThe average area of superficial FAZ area in the control group, NDR group and NPDR group were 0.314±0.103, 0.349±0.102, 0.416±0.148 mm2; the mean logMAR BCVA were 0.015±0.038, 0.029±0.059, 0.129±0.133; the mean CFT were 247.46±13.35, 244.13±25.09, 263.12±24.96 μm; the mean GCIPL thickness were 89.00±4.98, 86.06±4.43, 82.61±14.32 μm; the mean minimum GCIPL thickness were 84.85±3.18, 80.68±5.39, 71.19±19.94 μm, respectively. The superficial FAZ area, logMAR BCVA, CFT and the minimum thickness of GCIPL showed significant differences (F=4.660, 11.708, 6.891, 6.333; P=0.012, 0.000, 0.002, 0.003) among these three groups. Correlation analysis showed that the logMAR BCVA was positively correlated with the superficial FAZ area (r=0.335, P=0.001), negatively correlated with the mean GCIPL thickness (r=－0.348, P=0.001) and the minimum GCIPL thickness (r=－0.416, P=0.000), no significant correlated with the CFT (r=0.171, P=0.095). The superficial FAZ area was negatively correlated with the CFT (r=－0.262, P=0.010) and the minimum GCIPL thickness (r=－0.213, P=0.037), no significant correlated with the mean GCIPL thickness (r=－0.179, P=0.081).ConclusionsWith the aggravation of fundus lesions in patients with type 2 diabetic mellitus, the superficial FAZ area gradually expands, the minimum GCIPL thickness gradually becomes thinner and the BCVA gradually decreases. Both the superficial FAZ area and the GCIPL thickness are correlated with BCVA. The superficial FAZ area is correlated with CFT and the minimum GCIPL thickness.
ObjectiveTo observe the flow density (FD) of macular and optic disc and area of foveal avascular zone (FAZ) in severe nonproliferative diabetic retinopathy (S-NPDR).MethodsA prospective cross-sectional study. From October 2019 to April 2020, 31 eyes of 25 S-NPDR patients (S-NPDR group) who were diagnosed in the ophthalmological examination of Jiangsu Province Hospital and 30 eyes of 30 age- and sex-matched healthy volunteers (control group) were included in this study. Optical coherence tomography angiography (OCTA) was used to scan the macular area of 6 mm×6 mm and optic disc of 4.5 mm×4.5 mm. The software automatically divides it into three concentric circles centered on the macular fovea, which were foveal area with a diameter of 1 mm, parafoveal area of 1 to 3 mm, and foveal peripheral area of 3 to 6 mm. The area around the optic disc was divided into 8 areas: nasal upper, nasal lower, inferior nasal, inferior temporal, temporal lower, temporal upper, superior temporal and superior nasal. The FD of the optic disc, the superficial capillary layer (SCP) and deep capillary layer (DCP) of the retina and FAZ area were measured. The FD and FAZ area were compared between the two groups by independent sample t test. The correlation between FAZ area and FD was analyzed by Pearson correlation.ResultsIn parafoveal and perifoveal area, compared with the control group, the FD of SCP (t=6.470, 5.220; P＜0.001) and DCP (t=7.270, 7.370; P＜0.001) decreased in S-NPDR group. In foveal area, there was statistically significant difference in the FD of DCP between the two groups (t=2.250, P=0.030), while the difference in FD of SCP between the two groups was not statistically significant (t=0.000, P=0.900). The FAZ area in S-NPDR group was larger than that in control group, and the difference was statistically significant (t=2.390, P=0.030). The FD in the S-NPDR group was lower than that in the control group except the superior nasal, the difference was statistically significant (t=7.520, 5.000, 4.870, 3.120, 2.360, 2.120, 5.410, 5.560, 2.640; P＜0.05). Pearson correlation analysis showed that the FAZ area of S-NPDR was negatively correlated with FD of SCP (r=－0.513, P=0.004), and had no correlation with FD of DCP (r=0.034, P=0.859).ConclusionThe overall FD in macular area and optic disc of patients with S-NPDR decreased and the FAZ area enlarged.
The fovea avascular area (FAZ) is an area of the retina surrounded by a continuous capillary plexus that does not have any capillary structure of its own. FAZ is an important region for the formation of fine vision function. The changes of its morphology and surrounding capillary density reflect the degree of macular ischemia, and are closely related to retinal vascular diseases such as diabetic retinopathy, retinal vein occlusion, Coats disease, idiopathic macular telangiectasia, and retinopathy of prematurity. Early observation of FAZ region changes in patients with retinal vascular disease by optical coherence tomography angiography (OCTA) can evaluate the severity and prognosis of the disease. However, the measurement error of FAZ-related data is still a problem that cannot be ignored. At present, OCTA devices of various manufacturers have different methods and algorithms for measuring and analyzing FAZ, which makes it impossible to compare the measured data between different devices. It is believed that with the continuous progress of OCTA related technology, more accurate data of FAZ regional changes can be obtained, which will bring more help to clinical work.