Optical coherence tomography angiography (OCTA) is a new and noninvasive imaging technique that generates real-time blood flow pattern on chorioretinal vasculature. In order to apply this novel technology in the practice to diagnose and treat ocular fundus diseases, we need to further strengthen the quality of OCTA image acquisition and reporting specifications. We need to understand its technical principle, and multiple factors affecting the OCTA image acquisition and interpretation. Furthermore, In the process of image acquisition, as well as analysis and interpretation, we need to pay attention to the stratification, interpretation of blood flow signals and identification of artifacts of OCTA images.

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.

Objective To observe the difference of macular microvascular features in superficial and deep vascular plexi in patients with branch retinal vein occlusion (BRVO).Methods A total of 63 BRVO patients (63 eyes) were enrolled in this study. There were 28 males (28 eyes) and 35 females (35 eyes). The patients aged from 39 to 74 years, with the mean age of (59.76±8.48) years. All eyes were evaluated by optical coherence tomography angiography (OCTA). The macular angiography scan protocol covered a 3 mm×3 mm area. The focus of angiography analysis included superficial vascular plexus and deep vascular plexus. The following vascular morphological parameters were assessed in these two plexi: foveal avascular zone (FAZ) enlargement, capillary non-perfusion (CNP) occurrence, microvascular abnormalities (MA) appearance, and vascular congestion (VC) signs. The FAZ area was measured by the built-in software. The macular microvascular morphology changes in superficial and deep vascular plexi were compared through McNemar test. Results The superficial and deep plexi showed FAZ enlargement in 43 eyes (68.3％) and 50 eyes (79.4％), CNP in 51 eyes (81％) and 50 eyes (79.4％), MA in 62 eyes (98.4％) and 62 eyes (98.4％), VC in 23 eyes (36.5％) and 52 eyes (82.5％), respectively. FAZ area was (0.55±0.37) mm2. There was no difference in CNP (P=1.000) and MA (P=1.000) between superficial and deep plexi. But, there was difference in FAZ enlargement (P=0.039) and VC signs (P<0.001) between superficial and deep plexi.Conclusion Deep vascular plexus showed more FAZ enlargement and VC sign than superficial plexus in BRVO patients.

Objective To observe the alterations of macular vascular density and the area of foveal avascular zone (FAZ) in branch retinal vein occlusion (BRVO) eyes.Methods A retrospective case-control study. Forty-five patients with unilateral BRVO and macular edema were enrolled in this study. Optical coherence tomography angiography (OCTA) was performed on the BRVO and fellow eyes. The scanning region in the macular area was 3 mm×3 mm. Macular vascular density and FAZ area in the superficial and deep retinal capillary plexi were measured in all eyes. The values of macular vascular density and FAZ area between BRVO eyes and fellow eyes, affected sector and unaffected sector were compared.Results The mean overall vascular density measured in the entire scan was lower in BRVO eyes compared with fellow eyes in both the superficial and deep capillary plexus (t=14.186, 9.468;P<0.05). The reduce degree of vascular density in the deep capillary plexus (7.65％) was higher than that in the superficial plexus (7.27％). In the superficial plexus, the vascular density was lower in the affected sector and the unaffected sector of the BRVO eyes compared with the corresponding sector in the fellow eyes (t=15.386, 9.435;P<0.05). The FAZ area enlarged in the BRVO eyes compared with the fellow eyes in the superficial capillary plexus and in the deep capillary plexus (t=3.216, 5.119;P<0.05). The degree of enlargement of FAZ area in the deep capillary plexus (0.19 mm2) was higher than that in the superficial plexus (0.11 mm2).Conclusions In eyes with BRVO, quantitative OCTA measurements confirm that vascular density decreased and FAZ area enlarged in the superficial and deep capillary plexi. The reduce degree of vascular density and enlargement degree of FAZ area in the deep capillary plexus are higher than those in the superficial plexus.

Objective To observe the imaging features of the optical coherence tomography angiography (OCTA) of complex retinal arterial macroaneurysm (RAM).Methods Nineteen eyes of 19 patients with RAM were enrolled in this retrospective study. There were 1 male (1 eye) and 18 females (18 eyes). The patients aged from 62 to 85 years, with the mean age of 71.3 years. The fundus photography examination revealed the tumors were located in the 1 - 3 branch of the artery, which showed focal spindle-shaped or fusiform angiomatous dilatation. The fundus fluorescein angiography revealed the early uniform fluorescence of the tumor, and the tumor was a high-fluorescence leak in the late period. RAM was divided into exudative type and hemorrhagic type according to the literature and based on the ocular fundus appearance. In 19 eyes, 8 eyes were exudative RAM and 11 eyes were hemorrhagic RAM. All eyes were examined by OCTA, and the retinal blood flow images of 3 mm ×3 mm diameter were routinely collected to observe the OCTA imaging features.Results OCTA examination showed that the superficial RAM of all eyes had strong reflection signal connected with retinal artery. B-scan image showed smaller tumors in the lumen with strong reflection of expansion, or large tumor with peak-like uplift and the blood flow signals in the tumor body were abundant. The enface image clearly showed the three-dimensional shape of the tumor. Tumors with exudation or multi-level bleeding could be clearly documented for their bleeding range and boundary. The white signal co-localized with the superficial retinal blood vessels by the function of multi-color fluoroscopy. The pattern of blood flow density can also clearly show the three-dimensional shape of the tumor.Conclusion The complex RAM is a strong reflection signal in the superficial layer of retina, which is connected with the retinal vessels; B-scan images shows small tumors with a small piece of strong reflection and dilation, or large tumors with mountain-like elevation with abundant blood flow signals. En face image can clearly show the three-dimensional shape of the tumor.

Objective To observe the changes of retinal nerve fiber layer (RNFL) thickness in patients with Alzheimer's disease (AD).Methods Twenty eyes of 40 patients with mild and (or) moderate AD confirmed by clinical examination (AD group) were included in the study. There were 11 males and 9 females with an average age of (72.75±8.25) years. Age and gender-matched normal 20 objectives were in the normal control group. Among them, there were 11 males and 9 females with a mean age of (71.05±7.08) years. There was no significant difference in gender composition, age and intraocular pressure between the two groups (P>0.05). There were significant differences in visual acuity, cup disc ratio and mini-mental state examination score (P<0.05). All eyes underwent high-resolution optical coherence tomography (OCT) examination. With a diameter of 3.4 mm and a center on the center of the optic disc, circular fast scans on optic disc were performed to obtain an average disc RNFL thickness, signal threshold>6. Computer image analysis system was used to measure the RNFL thickness from superior, inferior, temporal and nasal quadrants, and the average RNFL thickness. The changes of RNFL thickness between the two groups and between different eyes of the same group were compared.Results Compared with the normal control group, the average (t=5.591), superior (t=8.169, 8.053) and inferior (t=12.596, 11.377) thickness of RNFL in both eyes in AD group were thinner, the differences were significant (P<0.05); the temporal (t=1.966, 0.838)and nasal (t=2.071, 0.916) thickness of RNFL in both eyes of AD group were thinner, but the difference was not statistically significant (P>0.05). There was no significant difference of the mean and different quadrant RNFL thickness between different eyes in AD group and normal control group (AD group:t=0.097, 0.821, 0.059, 0.020, 0.116; normal control group:t=0.791, 1.938,1.806, 2.058, 1.005;P>0.05).Conclusion The RNFL thickness around the optic disc in AD patients is thinner; This occurs first in superior and inferior quadrants of the optic disc.

Objective To observe the choroidal blood flow and morphological changes in patients with severe stenosis of internal carotid artery stenosis (ICAS).Methods A retrospective case-control study. Forty-six patients (46 eyes) with ICAS were enrolled in this study. There was severe stenosis in one side (the eyes in this side were set as case group) and mild or no stenosis in other side (the eyes in this side were set as control group). Color doppler ultrasound (CDI) was used to observe the changes of hemodynamic parameters of the ophthalmic artery (OA) and posterior ciliary artery (PCA),the main parameters of ultrasound Doppler imaging are peak systolic velocity (PSV), end diastolic velocity (EDV), resistance indices (RI) and the calculation of the pulsation indices (PI) through the use of a formula. Enhanced binarization of deep imaging coherence tomography (EDI-OCT) was used to measure the subfoveal choroidal thickness (SFCT). The total subfoveal choroidal area (TCA), luminal (LA), stromal (SA) and choroidal vascularity index (CVI) were obtained by modified image binarization technique.Results In the case group, the PSV in the OA and PCA was significantly lower than that of the control group (t=?2.200, ?2.612;P=0.030, 0.011). There were no significant differences in EDV, RI, PI of OA (t=0.337, ?1.810, ?1.848;P=0.737, 0.074, 0.068) and PCA (t=?1.160, 1.400, 0.815;P=0.249, 0.165, 0.417). The SFCT (t=?3.711,P<0.001), TCA (t=?2.736,P=0.007), LA (t=?3.188, P=0.002) and CVI (t=?2.096,P=0.039) of the case group was significantly lower than that of the control group. There were no significant differences in SA (t=?1.262,P=0.210) and LA/SA (t=?1.696,P=0.093).Conclusion In severe stenosis ICAS eyes, the PSV in the PCA and SFCT, TCA, LA, CVI are decreased.

Objective To observe the characteristics of multifocal microperimetry and its relationship with visual acuity and multifocal ganglion cell complex (GCC) in nonarteritic anterior ischemic optic neuropathy (NAION).Methods A retrospective case study. A total of 38 patients (54 eyes) with NAION were enrolled in this study. 25 NAION eyes (25 patients) and 29 contralateral health eyes (29 patients) were randomly selected into case group and control group respectively. All eyes underwent best corrected visual acuity (BCVA), slit lamp microscope, indirect ophthalmoscope, color fundus photography, optical coherence tomography (OCT), visual field and multifocal microperimetry. Logarithm of the minimum angle of resolution (logMAR) was used to calculate BCVA. There were no significantly differences on age (t=?0.647), gender, dominant eyes (χ2=0.128, 0.099), intraocular pressure (t=0.376) between two groups (P>0.05). Macular GCC thickness, superior and inferior GCC thickness were measured by OCT, focal loss volume (FLV) and global loss volume (GLV) were obtained at the same time. Microperimetry were measured by macular integrity assessment instrument (MAIA microperimetry), and mean retinal sensitivities (MS) in macular area 10° and fixation rate in the macular central 2° and 4° were determined. The relationship between MS, macular GCC and BCVA were analyzed by Spearman correlation analysis.Results The mean logMAR BCVA of case group and control group were 0.68±0.79 and 0.07±0.06, respectively. There was significantly statistical difference in MS between two groups (t=?2.507, P=0.037). There were no significantly statistical difference in mean GCC (t=?1.245,P=0.259), superior and inferior GCC (t=?1.336, ?1.024;P=0.230, 0.346), FLV (t=1.058,P=0.331) and GLV (P=0.182) between two groups. The correlation between BCVA and MS (r=?0.809,P=?0.005) was observed. However, there were no correlation between BCVA and GCC, superior and inferior GCC, FLV, GLV (r=?0.98, ?0.466, ?0.061, 0.442, 0.442;P=0.817, ?0.244, 0.885, 0.273, 0.273). And also, there were no correlation between MS and GCC, superior and inferior GCC, FLV, GLV (r=0.238, 0.524, 0.286, 0.643, ?0.619;P=0.570, 0.183, 0.493, 0.086, 0.102).Conclusions MS reduced in early stage NAION eyes, which did not correlate with macular GCC.

Objective To observe multimodality imaging features of different properties in multifocal choroiditis (MFC).Methods Twenty-eight patients (51 eyes) with MFC were enrolled in this study. There were 10 males and 18 females. The patients aged from 31 to 49 years, with the mean age of (41.5±0.8) years. There were 23 bilateral patients and 5 unilateral patients. All patients underwent best corrected visual acuity (BCVA), slit-lamp biomicroscopy, indirect ophthalmoscopy, fundus colorized photography, infrared fundus photography, fundus autofluorescence (FAF), fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) examinations. The lesions were classified as active inflammatory lesion, inactive inflammatory lesion, active choroidal neovascularization (CNV) and inactive CNV. The multimodality imaging features of different properties in MFC was observed.Results In fundus colour photography, the boundaries of active inflammatory lesions were blurry, while inactive inflammatory lesions had relatively clear boundaries. Secondary active CNV showed mild uplift and surrounding retinal edema; Secondary active CNV lesions showed mild uplift, retinal edema around the lesion; Secondary non-active CNV had no retinal exudate edema lesions, but had lesions fibrosis and varying degrees of pigmentation. Infrared fundus examination revealed that both active and inactive inflammatory lesions showed a uniform punctate or sheet-like fluorescence. The fluorescence of CNV lesions was not uniform; there was a bright ring around the strong fluorescence. FAF found that active inflammatory lesions showed weak autofluorescence (AF), surrounded by a strong fluorescence ring; inactive inflammatory lesions showed AF loss. Secondary active CNV lesions showed strong AF with a bright ring along the edge, and obscured fluorescence for co-occurred hemorrhagic edema; secondary non-active CNV lesions were strong AF, surrounded by a weak AF ring. FFA revealed that active inflammatory lesions showed weak fluorescence in the early stage, and fluorescence gradually increased in the late stage with slight leakage. Inactive inflammatory lesions showed typical transmitted fluorescence. Fluorescein leakage secondary to active CNV was significant;lesions secondary to inactive CNV showed scar staining. In OCT, the active inflammatory lesions showed moderately weak reflex signals in the protruding lesions under the retinal pigment epithelium (RPE). The inactive inflammatory lesions showed penetrable RPE defects or choroidal scar, it also showed clear RPE uplift lesions with a strong reflection signal. Secondary active CNV showed subretinal fluid retention; secondary non-active CNV showed RPE defects and choroidal scarring.Conclusions Active inflammatory lesions in MFC have blurred boundary, retinal edema and fluorescein leakage in FFA; inactive inflammatory lesions have clear boundary and typical transmitted fluorescence in FFA, and no retinal edema. Secondary active CNV showed subretinal fluid in OCT; and secondary non-active CNV showed RPE defects and choroidal scarring.

Objective To observe the clinical characteristics and treatment of cytomegalovirus retinitis (CMVR) in leukemia patients.Methods This is a retrospective analysis. Seven leukemia patients (13 eyes) with CMVR were studied. All patients underwent examinations of visual acuity, slit lamp microscope, ophthalmoscope, color fundus photography, peripheral blood CD4+T cell count and serum/aqueous CMV-DNA test. All patients were treated with ganciclovir or zoledronic acid combined with intravitreal injection of ganciclovir. The follow-up period was 3-14 months.Results Six patients were treated with hematopoietic stem cell transplantation and 1 patient was with chronic leukemia. All patients were CMV-DNA positive for serum, and 18.5％ (2/7) for aqueous humor. CMVR in leukemia patients showed mild anterior segment inflammation, ocular fundus with irregular yellowish-white retinal necrosis and radial hemorrhage (7 eyes). Some (2 eyes) also shoed gray and white granular retinal infiltrates. Intravenous ganciclovir/zoledronic acid combined with intravitreal injection of high concentration ganciclovir was an effective treatment, while systemic corticosteroids were effective in reducing vitreous opacity.Conclusions CMVR is characterized by progressive necrotic retinitis with hemorrhage and vasculitis. Intravenous ganciclovir/zoledronic acid combined with intravitreal injection of ganciclovir is effective in the treatment of CMVR with leukemia.