الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Choroidal neovascularization (CNV) can occur as a result of a variety of ophthalmologic diseases, such as neovascular age-related macular degeneration (AMD), high myopia, central serous chorioretinopathy (CSCR), and others. These abnormal blood vessels typically are derived from the choroidal vasculature and can penetrate Bruch’s membrane into the space beneath the retinal pigment epithelium (RPE; type 1 CNV) or the subretinal space (type 2 CNV). In some eyes, neovascularization seems to begin from the retinal vasculature, eventually anastomosing with new vessels derived from the choroidal vasculature (retinal angiomatous proliferation (RAP), also called type 3 CNV).1 Early diagnosis and visualization of CNV are crucial for initiating and guiding treatment, which in most cases is an intravitreal anti-vascular endothelial growth factor (Anti-VEGF) drug to prevent progressive, irreversible vision loss.2
Optical coherence tomography angiography may be captured with spectral domain OCT (SD OCT), which in commercial devices employs a wavelength at around 840nm, or with swept-source OCT (SS OCT), which uses a longer wavelength (1050nm). The area that can be scanned within this time frame depends on the A-scan rate of the system. With commercially available OCT machines (up to 70 kHz for spectrometer-based systems and up to 100 kHz for swept-source based systems), areas of either 3 × 3 mm, 6 × 6 mm, and 9 × 9 mm are typically scanned with decreasing oversampling rates.8
While OCT is considered a cross-sectional imaging modality, OCTA images are mainly studied with en face visualization. The en face approach integrates the 3- dimensional volumetric information acquired from previously established OCT techniques for the automated segmentation of anatomic reference planes, which allow the definition of “slabs” and the segmentation of the volumetric scans at
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specific depths. These segmented slabs are reconstructed in the coronal plane similar to a standard fundoscopic image.6
En face OCTA images of the choriocapillaris (CC) are generated by segmenting the Bruch’s membrane, and then positioning a second boundary several microns below (external to) to yield a thin slab with a thickness of 10-30-μm.6 On OCTA, the neovascular lesion morphology normally corresponds to either ‘‘medusa’’ pattern, in which vessels are radiating in all directions from the center of the lesion, ‘‘seafan’’ pattern, in which vessels are radiating from one side of the lesion, or a glomerulus-shaped lesion in the outer retina or an ill-defined pattern. A long-filamentous-vessel or a “pruned tree” appearance also can be seen.8
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The main results of the study revealed that:
As demonstrated in Figure 19, 43 (57%) patients were females, while 33 (43%) were males. The male to female ratio in our study group was 1:1.3.
As demonstrated in Figure 20, 66 (87%) patients were Caucasian, while 10 (13%) were black. The Caucasian to black ratio in our study group was 7:1.
As demonstrated in Figure 21, the right eye was mainly involved in 33 (43%) patients, while the left eye was mainly involved in 43 (57%) patients. The right to left ratio in our study group was 1:1.3.
The mean disease duration of enrolled patients was 5.2 ± 3.1 years, ranging from 1 to 10 years. As shown in Figure 22, patients were classified into four groups, less than 3 years (n = 20), between 3 and 6 (n = 24), between 6 and 9 (n = 23), and more than 9 years (n = 9).
As demonstrated in Figure 23, 12 (16%) patients reported previous laser photocoagulation, 10 (13%) patients reported receiving medications, 22 (29%) patients reported receiving supplements, and 32 (42%) patients did report any prior AMD therapy.
The mean BCVA of enrolled patients as by LogMAR score was 0.68±0.27, ranging from 0.2 to 1.2. As shown in Figure 24, patients were classified into three groups, less than 0.3 (n = 7), between 0.7 and 0.3 (n = 35), and more than 0.7 (n = 34).
The mean IOP of enrolled patients 15.5 ± 3.6 mmHg, ranging from 10 to 21 mmHg. As shown in Figure 25, patients were classified based in IOP into two groups, where 31 (41%) patients had IOP less than 15 mmHg, and 45 (59%) patients had an IOP of 15 or more mmHg.
As demonstrated in Figure 26, the majority of patients (53%) demonstrated type 1 CNV observed by OCTA as a neovascular complex between the RPE and Bruch’s membrane, originating in the choroid.
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Type II CNV was reported in 24 (32%) patients visualized as a neovascular network that grows from the choroid vasculature and traverses the RPE-Bruch’s membrane complex into the subretinal space.
Type III CNV was demonstrated by 12 (15%) patients as intraretinal anastomoses originating in the deep capillary plexus of the retina.
As demonstrated in Figure 27, five different patterns could be identified by OCTA for the newly formed blood vessels. The most commonly encountered pattern was medusa, demonstrated by 23 (30%) patients. Nineteen (25%) patients demonstrated the glomerulus pattern, 15 (20%) patients demonstrated the sea-fan pattern, 11 (15%) demonstrated indistinct pattern, and only eight (10%) patients showed long filamentous vessels or pruned tree pattern.
The mean area of CNV was 7.6 ± 3.9 DA, ranging from 1.3 to 14.9 DA. As shown in Figure 28, patients were classified into three groups based on area of CNV, less than 5 DA (n = 21eyes) 28%, between 5 and 10 DA (n = 32 eyes) 42%, and more than 10 DA (n = 23 eyes) 30%.
The mean of CRT as measured by OCTA was 291 ± 51 μm, ranging from 200 to 296 μm. As shown in Figure 29, patients were classified into two groups based on CRT, less than 300 μm (n = 51), and 300 μm or more (n = 25).
As illustrated by Figure 30, subretinal fluid was detected in 31 (41%) patients, and intraretinal fluid was detected in 16 (21%) patients. On the other hand, 29 of patients (38%) did not demonstrate any retinal fluid collection.
Table 4. shows demographic and clinical data in different CNV morphology patterns.
Relation between VA (LogMAR) and variables illustrated in Table 5.
Table 6. VA (LogMAR) correlation with duration of AMD, Area of CNV and CRT.