Demyelinating plaque-associated uveitis.

PURPOSE: To report the clinical and fluorescein angiographic (FA) features of demyelinating plaque-associated uveitis (DPU), a subset of uveitis in which patients have demyelinating plaques on the brain/cervical magnetic resonance image (MRI) but do not meet the criteria for multiple sclerosis (MS). METHODS: In this retrospective observational study, Persian Patients were diagnosed with DPU and included if (1) they never satisfied the MS criteria, (2) all other possible etiologies were excluded, and (3) they were followed for at least 2 years. RESULTS: After a median follow-up of 3 years (interquartile range, 2.0-5.3), 8 out of 40 (20%) patients diagnosed with DPU were excluded as they subsequently met the MS criteria. Of remaining 32 patients studied, the mean age was 36.3±9.9 (range 20-56 years), and 30 (93.8%) were female. Twenty-four (75.0%) showed bilateral involvement and 27 (84.4%) had insidious-chronic course. Uveitis was classified as intermediate (with or without anterior uveitis) in 29 (90.6%) and isolated anterior in 3 (9.4%) patients. Nine (28.1%) patients had at least one systemic neurological complaint. Ocular findings were: granulomatous keratic precipitates in 43/44 (97.7%) eyes; snowballs in 25/52 (48.1%) eyes; snowbanks in 4/52 (7.7%) eyes; cystoid macular edema in 20/56 (35.7%) eyes; and optic neuritis in 5/56 (8.9%) eyes. Visual acuity was ≥ 20/40 in 39 eyes (69.6%) at presentation which improved to 46 eyes (81.2%) at 2-year follow up. The two most frequent findings in FA were optic disc leakage/staining in 44/52 (81.5%) eyes, and peripheral retinal perivascular leakage in 39/52 (76.9%) eyes, which in 14/52 (26.9%) eyes extended beyond the equator. CONCLUSION: DPU usually presents as a bilateral chronic granulomatous intermediate and, less often, isolated anterior uveitis, especially in females. Most are neurologically asymptomatic. Visual outcome is generally favorable. In FA, peripheral retinal perivascular leakage is common. DPU patients have an increased tendency to develop MS and should be prohibited from anti-TNF treatment.

Central retinal vein and artery occlusion associated with sildenafil: a case report and review of the literature.

BACKGROUND: Sildenafil is a selective phosphodiesterase type 5 inhibitor used for the treatment of erectile dysfunction and pulmonary hypertension. It is available over the counter in many countries. While there have been a few reports of retinal vascular occlusion following sildenafil consumption, most cases have other comorbidities as risk factors for the disease, and the exact causal role of this drug in these conditions remains unclear. CASE PRESENTATION: We present the case of a healthy 32-year-old Iranian man who developed combined central retinal vein occlusion and retinal artery occlusion following sildenafil exposure. The patient underwent a hypercoagulative state workup for possible underlying risk factors. Additionally, we conducted a literature search on PubMed using the keywords: retinal vein occlusion AND Sildenafil OR Viagra, retinal artery occlusion AND Sildenafil OR Viagra, retinal vascular occlusion AND Sildenafil OR Viagra. To obtain more objective results in the reviews, we employed an adverse drug reaction possibility algorithm. The patient was found to be otherwise healthy, and ancillary tests were unremarkable. A literature review identified seven reports of retinal vascular occlusion following sildenafil use. In most of these cases, the role of sildenafil was not clearly established. To the best of our knowledge, our case achieved the highest score based on the algorithm compared with previous reports. CONCLUSION: Sildenafil may be associated with severe retinal vascular accidents in otherwise healthy young individuals.

Ocular safety of intravitreal ethylene diamine tetra acetic acid (EDTA): An experimental feasibility study.

Ethylene diamine tetra acetic acid (EDTA) is a chelating component that is able to diminish oxidative reactivity and can be a potential neuroprotective drug in various ocular diseases. For assessing the safety of intravitreal EDTA, 10 rabbits were allocated and divided into 5 groups. Right eyes of the animals received intravitreal EDTA (112.5, 225, 450, 900 and 1800 µg /0.1 ml). Fellow eyes were considered as controls. Clinical examinations and electroretinography (ERG) were performed at the baseline and on day 28. The enucleated eyes were subjected to hematoxylin and eosin (H&E) staining, immunohistochemistry for glial fibrillary acidic protein (GFAP) and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test. Clinical examinations, H&E staining and TUNEL assay were unremarkable. The ERG test did not exhibit any significant alteration compared to the baseline values, except for a significant decrease in just one measurement of the eyes injected with 225 µg EDTA. The mean scores of GFAP immune reactivity in the eyes injected with 112.5 and 225 µg EDTA indicated a non-significant reaction. The scores in higher doses were significant. We suggest intravitreal EDTA with a dose threshold of < 450 µg should be studied for ratification of the safe dose.

Accuracy of peripapillary OCTA in patients with acute nonarteritic anterior ischemic optic neuropathy.

OBJECTIVE: To evaluate the accuracy of peripapillary optical coherence tomography angiography (OCTA) segmentation in eyes with acute nonarteritic anterior ischemic optic neuropathy (NAION) and healthy eyes. METHOD: In this retrospective study, en face OCTA images of the optic disc of healthy eyes and eyes with unilateral acute NAION were obtained. The disc boundary and radial peripapillary capillary (RPC) segmentation were generated automatically by the instrument software and then corrected by 2 expert investigators. The frequency of segmentation errors and its impact on vessel density and nerve fibre layer (NFL) thickness measurements were evaluated. RESULTS: Thirty-eight eyes of 38 subjects (18 in the healthy group and 20 in the acute NAION group) were studied. A misidentified disc border was noted in 5 healthy eyes (27.7%) and 19 eyes with NAION (95.0%; p < 0.001). Segmentation error at the RPC level was found in 6 healthy eyes (33.33%) and 19 eyes with NAION (95.0%; p < 0.001). The nerve fibre layer thickness and RPC density did not change statistically significantly after error corrections in both groups. CONCLUSIONS: Misidentification of disc border and segmentation error of the RPC layer are common in OCTA images of the optic disc. Accuracy of OCTA imaging in disc boundary detection and RPC network segmentation is reduced in edematous optic discs following acute NAION.

Differentiating a pachychoroid and healthy choroid using an unsupervised machine learning approach.

The purpose of this study was to introduce a new machine learning approach for differentiation of a pachychoroid from a healthy choroid based on enhanced depth-optical coherence tomography (EDI-OCT) imaging. This study included EDI-OCT images of 103 eyes from 82 patients with central serous chorioretinopathy or pachychoroid pigment epitheliopathy, and 103 eyes from 103 age- and sex-matched healthy subjects. Choroidal features including choroidal thickness (CT), choroidal area (CA), Haller layer thickness (HT), Sattler-choriocapillaris thickness (SCT), and the choroidal vascular index (CVI) were extracted. The Haller ratio (HR) was obtained by dividing HT by CT. Multivariate TwoStep cluster analysis was performed with a preset number of two clusters based on a combination of different choroidal features. Clinical criteria were developed based on the results of the cluster analysis, and two independent skilled retina specialists graded a separate testing dataset based on the new clinical criteria. TwoStep cluster analysis achieved a sensitivity of 1.000 (95-CI: 0.938-1.000) and a specificity of 0.986 (95-CI: 0.919-1.000) in the differentiation of pachy- and healthy choroid. The best result for identification of pachychoroid was obtained for a combination of CT, HR, and CVI, with a correct classification rate of 0.993 (95-CI: 0.980-1.000). Based on the relative variable importance (RVI), the cluster analysis prioritized the choroidal features as follows: HR (RVI: 1.0), CVI (RVI: 0.87), CT (RVI: 0.70), CA (RVI: 0.59), and SCT (RVI: 0.27). After performing a receiver operating characteristic curve analysis on the cluster membership variable, a cutoff point of 389 µm and 0.79 was determined for CT and HR, respectively. Based on these clinical criteria, a sensitivity of 0.793 (95-CI: 0.611-0.904) and a specificity of 0.786 (95-CI: 0.600-0.900) and 0.821 (95-CI: 0.638-0.924) were achieved for each grader. Cohen's kappa of inter-rater reliability was 0.895. Based on an unsupervised machine learning approach, a combination of the Haller ratio and choroidal thickness is the most valuable factor in the differentiation of pachy- and healthy choroids in a clinical setting.

Optical Coherence Tomography Angiography Findings after Acute Intraocular Pressure Elevation in Patients with Diabetes Mellitus versus Healthy Subjects.

Purpose: To assess the changes in optic nerve head and macular microvascular networks after acute intraocular pressure (IOP) rise in healthy eyes versus the eyes of diabetic patients. Methods: In this prospective, interventional, comparative study, 24 eyes of 24 adults including 12 eyes of healthy nondiabetic subjects and 12 eyes with mild or moderate non-proliferative diabetic retinopathy (NPDR) were enrolled. IOP elevation was induced by a suction cup attached to the conjunctiva. IOP and optical coherence tomography angiographic (OCTA) images of the optic disc and macula were obtained before and immediately after the IOP rise. Results: Baseline and post-suction IOPs were not significantly different between the two groups (all P > 0.05). The mean IOP elevation was 13.93 ± 3.41 mmHg among all eyes and was statistically significant as compared to the baseline in both groups (both P < 0.05). After IOP elevation, healthy eyes demonstrated a reduction in the vessel density in the whole image deep and superficial capillary plexuses and parafoveal deep capillary plexus (DCP) (all P < 0.05). In diabetic retinopathy, foveal vessel density at DCP decreased significantly following IOP rise (P = 0.003). In both groups, inside disc vessel density decreased significantly after IOP rise (both P < 0.05), however, no significant change was observed in peripapillary vessel density (both P > 0.05). Conclusion: Acute rise of IOP may induce different levels of microvascular changes in healthy and diabetic eyes. Optic disc microvasculature originating from the posterior ciliary artery may be more susceptible to IOP elevation than that of retinal microvasculature.

Intravitreal recombinant tPA before vitrectomy for diabetic tractional retinal detachment: A randomized controlled trial.

PURPOSE: To investigate the effect of intravitreal recombinant tissue plasminogen activator (rt-PA) injection before vitrectomy on surgical facility and outcome in diabetic tractional retinal detachments (TRD). METHODS: Prospective, randomized, interventional clinical trial. A total of 38 eyes with diabetic TRD were candidates for vitrectomy. Patients were randomized 1:1 to receive intravitreal rt-PA, five to seven days before vitrectomy or no injection. Intraoperative surgical facility and anatomic success at month 3 after surgery were assessed. RESULTS: Mean patient age was 54.2 ± 9.4 years. There was no statistically significant difference between rt-PA and no injection groups with regard to anatomic success (89% versus 95%, respectively, P = 0.547) and best corrected visual acuity at 3 months (2.0 versus 2.1 logMAR, respectively, P = 0.840). However, surgical facility score was statistically significantly lower in rt-PA injection group compared to no injection group (4.1 ± 1.7, 5.8 ± 2.0, respectively, P = 0.007). CONCLUSIONS: Vitrectomy for TRD was easier after preoperative rt-PA injection, without affecting the anatomic and visual outcomes.

"Inverted Snowing-Cloud" Sign in Endogenous Candida Endophthalmitis.

Candida spp. is the most common cause of endogenous fungal endophthalmitis. The diagnosis of this rare disease is based on clinical findings supported by positive blood culture. Recently, it has been shown that optical coherence tomography (OCT) characteristic findings are beneficial in making a correct diagnosis of fungal infection in cases with endogenous endophthalmitis. The current photo-essay aims to highlight the role of OCT in diagnosis of Candida endogenous endophthalmitis where OCT imaging of one of the retinal lesions disclosed a pre-retinal hyper reflective lesion with overlying punctate vitreous opacities. We propose "inverted snowing-cloud" sign for this OCT pattern considering the resemblance of the vitreous opacities to snowflakes.

The effect of intravitreal recombinant tissue plasminogen activator injection on diabetic tractional fibrovascular membranes: Proposed criteria using optical coherence tomography.

PURPOSE: To evaluate the effect of intravitreal recombinant tissue plasminogen activator (tPA) on diabetic tractional fibrovascular membranes (FVM) using proposed optical coherence tomography (OCT) criteria. METHODS: This prospective, interventional case series enrolled eyes with tractional retinal detachment who were candidates for pars plana vitrectomy. OCT images were obtained to evaluate the border of the attached-detached retina and overlying FVP at baseline and 1 week post-intravitreal tPA injection using the follow-up scan acquisition protocol. Two independent graders assessed retinal detachment (RD) height, FVM height, and retinal thickness at the site of membrane attachment. RESULTS: Thirteen eyes from 13 individuals were included. Assessment of RD height, FVM height, and retinal thickness at membrane attachment point were feasible at both visits in 10/13 (77%), 10/13 (77%), and 8/13 (62%) of eyes, respectively. There was excellent agreement between the two graders for all measurements (all ICC > 0.94). Release of the retina-membrane attachment point was not observed in any eyes. No statistically significant change was found in any of the measured parameters. CONCLUSIONS: Excellent agreement was achieved between the graders for quantitative assessment of diabetic FVM using our proposed OCT criteria. We did not observe a significant change in the FVM measurements, 1-week after intravitreal tPA injection.

Segmentation Error Correction of the Optical Coherence Tomography Angiography Images in Peer-Reviewed Studies.

Purpose: To assess the percentage of published articles reporting optical coherence tomography angiography (OCTA) metrics regarding the report of segmentation error correction. Methods: A comprehensive search was conducted using the PubMed database for articles on OCTA imaging published between January 1, 2015, and January 1, 2021. All original articles reporting at least one of the OCTA metrics were extracted. The article text was reviewed for the segmentation correction strategy. In addition, the number of articles that mentioned the lack of segmentation error correction as a limitation of the study was recorded. Results: From the initial 5288 articles, 1559 articles were included for detailed review. One hundred ninety-six articles (12.57%) used manual correction for segmentation errors. Of the remaining articles, 589 articles (37.8%) excluded images with significant segmentation errors, and 99 articles (6.3%) mentioned segmentation errors as a limitation of their study. The rest of the articles (675, 43.3%) did not address the segmentation error. Multiple logistic regression analysis revealed that ignorance of segmentation error was significantly associated with lower journal ranks, earlier years of publication and disease category of age-related macular degeneration, and glaucoma (all P < 0.001). Conclusions: A significant proportion of peer-reviewed articles in PubMed, disregarded the segmentation error correction. The conclusions of such studies should be interpreted with caution. Editors, reviewers, and authors of OCTA articles should pay special attention to the correction of segmentation errors.

Spatial distribution of diabetic capillary non-perfusion.

OBJECTIVE: To evaluate the distribution of capillary non-perfusion (CNP) in superficial and deep capillary plexuses (SCP and DCP) in eyes with diabetic retinopathy (DR). METHODS: In this retrospective case series, macular optical coherence tomography angiography (OCTA) images were obtained from eyes with DR without diabetic macular edema (DME). The area of CNP in SCP and DCP was delineated using an automated approach after excluding the foveal avascular zone (FAZ) and major retinal vessels. The distribution and spatial correlation of the CNP in each layer were analyzed. RESULTS: Forty-three eyes of 27 patients with DR with a mean age of 59.10 ± 9.05 years were included. The mean CNP area in SCP was statistically significantly higher than DCP (0.722 ± 0.437 mm2 vs. 0.184 ± 0.145 mm2 , respectively, p < .001). There was a statistically significant association between mean BCVA (0.28 ± 0.21 logMAR) and CNP area in DCP (p = .01). After automated subtraction of CNP areas in DCP from SCP, 25.43 ± 15.05% of CNP areas in the DCP had co-localized CNP areas in SCP. The CNP percentage was statistically significantly different between the concentric rings on foveal center, both in SCP and in DCP (both p < .001) showing a decreasing trend from the outer ring toward the center. CONCLUSION: In DR, SCP is more ischemic than DCP. This is in contrast to the previously described oxygenation-dependent ischemic cascade following acute retinal vascular occlusions. This study provides further insight into the retinal ischemia in DR.

Artifacts in Optical Coherence Tomography Angiography.

We performed a comprehensive search of the published literature in PubMed and Google Scholar to identify types, prevalence, etiology, clinical impact, and current methods for correction of various artifacts in optical coherence tomography angiography (OCTA) images. We found that the prevalence of OCTA image artifacts is fairly high. Artifacts associated with eye motion, misidentification of retinal layers, projections, and low optical coherence tomography signal are the most prevalent types. Artifacts in OCTA images are the major limitations of this diagnostic modality in clinical practice and identification of these artifacts and measures to mitigate them are essential for correct diagnosis and follow-up of patients.

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.

Optic pit-like maculopathy in a patient without any detectable disc anomalies.

Macular schisis is the splitting of the inner retinal layers at macula, with or without associated detachment. The acquired form of macular schisis is frequently associated with optic disc pit maculopathy, although it could be accompanied by several conditions such as tractional maculopathies, cystoid macular edema, veno-occlusive disease, and shaken baby syndrome. However, a small number of cases of retinoschisis without optic disc pit have been reported elsewhere. Here, we present a patient with acquired macular schisis without high myopia and optic disc abnormality in funduscopic examination and imaging. Macular optical coherence tomography of her left eye revealed schisis of the inner and outer retinal layers and subretinal fluid and choroidal thickness of 426 µm (pachychoroid). Although the optic disc of this patient appeared normal, the probable presumption is that small junctions existed between the macular neuroretinal tissue and the vitreous cavity. Further studies are required to survey the other probable mechanisms of retinoschisis without optic pit with more subjects.

Macular microvascular changes after intravitreal bevacizumab injection in diabetic macular edema.

OBJECTIVE: To evaluate the changes in retinal capillary plexus and the choriocapillaris after a single intravitreal injection of bevacizumab in eyes with diabetic macular edema using optical coherence tomography angiography (OCTA). DESIGN: Prospective interventional case series. PARTICIPANTS: Patients having diabetes with centre-involving diabetic macular edema. METHODS: In this prospective interventional case series, eyes with centre-involving diabetic macular edema were enrolled. Vascular density (VD), vascular diameter index (VDI), vascular length density (VLD), foveal avascular zone (FAZ) area, and foveal density (FD)-300 were measured using en face OCTA images before and 1 month after administration of intravitreal bevacizumab. VD and VDI measurements were performed in the superficial capillary plexus (SCP) and deep retinal capillary plexus (DCP) and in the choriocapillaris. Additionally, capillary nonperfusion area (CNPA) was detected automatically based on vessel distance map in 4 concentric rings around the foveal centre. The segmentation error was manually corrected, and the measurements were performed by 2 expert graders. RESULTS: Twenty-three eyes of 19 patients with a mean age of 62.76 ± 6.88 years were included. There were no significant changes in the FAZ area, FD-300, or in the VD of the foveal and parafoveal SCP and DCP. Also, VLD and VDI of the SCP and DCP remained unchanged. The change in the CNPA was not statistically significant. The VD of choriocapillaris increased significantly after injections (p = 0.005). CONCLUSIONS: FAZ area and VD of the retinal capillary plexus remained stable in the short-term period after intravitreal bevacizumab. In addition, the choriocapillaris blood flow improved after bevacizumab injection.

Superficial and Deep Foveal Avascular Zone Area Measurement in Healthy Subjects Using Two Different Spectral Domain Optical Coherence Tomography Angiography Devices.

PURPOSE: To compare the area of the foveal avascular zone (FAZ) in the superficial and deep retinal layers using two different spectral-domain optical coherence tomography angiography (OCTA) devices. METHODS: A cross-sectional comparative study was conducted to obtain macular OCTA images from healthy subjects using Optovue RTVue XR Avanti (Optovue, Inc, Fremont, CA) and Spectralis HRA+OCTA (Heidelberg Engineering, Heidelberg, Germany). Two independent trained graders measured the FAZ area using automated slab segmentation. The FAZ area in the superficial and deep retinal layers were compared. RESULTS: Twenty-three eyes of 23 subjects were included. The graders agreement was excellent ( > 0.86) for all measurements. The mean FAZ area was significantly larger at the superficial retinal layer as compared to the deep retinal layer on both devices (0.31 ± 0.08 mm 2 vs 0.26 ± 0.08 mm 2 in Optovue and 0.55 ± 0.16 mm 2 vs 0.36 ± 0.13 mm 2 in Spectralis, both P < 0.001). The mean FAZ area was significantly greater in the superficial and deep retinal layers using Spectralis as compared to Optovue measurements (P < 0.001 for both comparisons). CONCLUSION: In contrast to previous reports, the FAZ area was larger in the superficial retina as compared to deep retinal layers using updated software versions. Measurements from different devices cannot be used interchangeably.

Quantitative analysis of optical coherence tomography angiography metrics in diabetic retinopathy.

PURPOSE: To evaluate the correlation of the visual acuity and diabetic retinopathy stage using optical coherence tomography and optical coherence tomography angiography metrics. METHODS: In this prospective study, optical coherence tomography and optical coherence tomography angiography images of patients with different stages of diabetic retinopathy were obtained. In optical coherence tomography angiography images, the size of foveal avascular zone, central macular thickness, and vessel density at superficial and deep capillary layers of the macula were measured. In optical coherence tomography images, the presence of intraretinal cyst, disorganization of retinal inner layer, and ellipsoid zone and external limiting membrane disruption were evaluated. The associations between the variables with visual acuity and diabetic retinopathy stage were analyzed. RESULTS: In total, 68 eyes of 38 patients with a mean age of 58.96 ± 10.59 years were included. In total, 34 eyes were categorized as non-proliferative diabetic retinopathy, 14 as active, and 20 as regressed proliferative diabetic retinopathy. Univariate analysis showed deep parafoveal vessel density, central macular thickness, ellipsoid zone disruption, disorganization of retinal inner layer, and external limiting membrane disruption had a significant relationship with visual acuity. However, in multivariate analysis, only central macular thickness and ellipsoid zone disruption had significant association with visual acuity (p = 0.02 and p = 0.01, respectively). There was a significant difference in deep parafoveal vessel density (p = 0.04), but not in foveal avascular zone area, between different stages of diabetic retinopathy. CONCLUSION: In this study, the foveal avascular zone area did not correlate with visual acuity and different stages of diabetic retinopathy. Structural abnormalities on optical coherence tomography images with especial focus on outer retinal disruption provided more reliable predictors for visual acuity outcomes in patients with diabetic retinopathy.

Effect of segmentation error correction on optical coherence tomography angiography measurements in healthy subjects and diabetic macular oedema.

PURPOSE: To evaluate the impact of segmentation error on vessel density measurements in healthy eyes and eyes with diabetic macular oedema (DMO). METHODS: In this prospective, comparative, non-interventional study, enface optical coherence tomography angiography (OCTA) images of the macula from healthy eyes and eyes with DMO were acquired. Two expert graders assessed and corrected the segmentation error. The rate of segmentation error and the changes in vessel density and inner retinal thickness after correction of the segmentation error were recorded and compared between the two groups. RESULTS: 20 eyes with DMO and 24 healthy eyes were evaluated. Intergrader agreement was excellent (intraclass correlation coefficient ≥0.9) for all parameters in both groups. The rate of segmentation error was 33% and 100% in healthy and diabetic eyes, respectively (p<0.001). Nine healthy eyes (37.5%) and all eyes with DMO (100%) were noted to exhibit a change in at least one of the foveal or parafoveal vessel density measurements. The rate of any change in foveal and parafoveal vessel densities in both the superficial and deep capillary plexus was statistically significantly higher in the diabetic group (all p<0.001). No statistically significant change was observed in mean vessel density (superficial and deep capillary plexuses) after correction of the segmentation error in healthy and DMO eyes (All p>0.05). However, the mean absolute change in the vessel density measurements was statistically significantly higher in the diabetic group (all p<0.05). The mean absolute change in superficial and deep inner retinal thickness was statistically significantly higher in DMO (p=0.02 and p=0.002, respectively). CONCLUSIONS: In this study, misidentification of retinal layers and consequent vessel density measurement error occurred in all eyes with DMO and in one-third of healthy eyes. The segmentation error should be checked and manually corrected in the OCTA vessel density measurements, especially in the presence of macular oedema.

En Face OCT of Type 2 Neovascularization:A Reappraisal of the Pitchfork Sign.

BACKGROUND AND OBJECTIVES: To describe a new en face optical coherence tomography (OCT) imaging feature of type 2 choroidal neovascularization (CNV) and illustrate the OCT angiographic (OCTA) findings in these eyes. PATIENTS AND METHODS: Multimodal images of patients with type 2 CNV who displayed the typical "pitchfork" sign with cross-sectional OCT were reviewed. Corresponding en face structural OCT and OCTA images were analyzed to correlate the finding before and after anti-vascular endothelial growth factor (VEGF) therapy. RESULTS: Five eyes of five patients, including two females and three males with a median age of 13 years (range: 8 years to 84 years), were studied. The etiology for type 2 CNV was laser-induced maculopathy in two eyes, idiopathic in two eyes, and age-related macular degeneration in one eye. None of the eyes had evidence of inflammatory ocular disease. En face OCT displayed a characteristic wreath-like pattern of hyperreflective spikes surrounding the type 2 neovascular membrane that originated from the ellipsoid zone and extended into the outer nuclear layer. Wreath-like spikes resolved with intravitreal anti-VEGF injection with good visual outcomes and transformation of the neovascular lesion from a type 2 to type 1 morphology. CONCLUSIONS: Type 2 CNV associated with the pitchfork sign with cross-sectional OCT displayed a characteristic wreath-like pattern of hyperreflective spikes with en face OCT that resolved with anti-VEGF therapy. This form of type 2 neovascularization may occur in eyes with different underlying etiologies and without signs of intraocular inflammation and is not limited to pediatric patients. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:719-725.].