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. © 2021, The Author(s)

Electroretinogram changes following sequential panretinal photocoagulation for proliferative diabetic retinopathy

Purpose: To evaluate changes in electroretinogram (ERG) response over the course of multiple sessions of panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PRP). Methods: A prospective cohort study of 11 patients with PDR who required PRP was conducted. PRP was completed over three sessions. Each patient had five ERGs done: baseline, 1 week after each PRP session, and 6 weeks after the last session of PRP. Dark-adapted 0.01 ERG, Dark-adapted 3 ERG, Dark-adapted 10 ERG, Light-adapted 3 ERG, and Light-adapted 30 Hz flicker ERG were done. The mean change in a-and b-wave amplitudes as well as implicit times compared to baseline was analyzed. Results: A significant reduction in peak amplitudes of both a-and b-waves and delay in latencies were observed in all responses (p<0.05). The absolute amplitude reduction and delay in latency were higher for scotopic b-waves (p<0.05). The root mean square (RMS) of Dark-adapted 10.0 ERG (p<0.05) and total mean amplitude changes of a-and b-waves (p<0.001) were reduced after each laser session; however, the magnitude of change was not different between the first, second, or third sessions of PRP, and each session showed a similar deterioration rate of ERG parameters comparing to each other (p=0.4 for RMS and p=0.2 for total mean amplitude changes). In addition, the results indicated recovery of the amplitude and latency of ERG waves after 6 weeks from the final treatment (p<0.001) although not to baseline levels. Conclusion: ERG findings following PRP show reduced retinal function after each session which partially recovers by 6 weeks after the completion of therapy. Clinicians should be mindful of these changes when planning the treatment course for patients with PDR. © 2020 Khojasteh et al

Diabetic retinopathy clinical practice guidelines: Customized for Iranian population

Purpose: To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population. Methods: Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology Preferred Practice Pattern 2012, and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefts, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9. Results: Agreed recommendations were accepted as the fnal recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence. Conclusion: This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy. © 2016 Journal of Ophthalmic and Vision Research

Intravitreal injection of anti-vascular endothelial growth factor agents for ocular vascular diseases: Clinical practice guideline

Purpose: To provide the clinical recommendations for the administration of intravitreal anti-vascular endothelial growth factor (VEGF) drugs especially bavacizumab for ocular vascular diseases including diabetic macular edema, neovascular age-related macular degeneration, myopic choroidal neovascularization, retinal vein occlusion and central serous chorioretinopathy. Methods: Twenty clinical questions were developed by the guideline technical committee. Relevant websites and databases were searched to find out the pertinent clinical practice guidelines to answer the questions. The technical committee provided possible answers (scenarios) according to the available evidences for each question. All scenarios along with their levels of evidence and the supported articles were sent to the experts for external review. If the experts did not agree on any of the scenarios for one particular clinical question, the technical committee reviewed all scenarios and their pertinent evidences and made the necessary decision. After that, the experts were asked to score them again. All confirmed scenarios were gathered as the final recommendations. Results: All the experts agreed on at least one of the scenarios. The technical committee extracted the agreed scenario for each clinical question as the final recommendation. Finally, 56 recommendations were developed for the procedure of intravitreal anti-VEGF injection and their applications in the management of ocular vascular diseases. Conclusion: The implementation of this guideline can standardize the management of the common ocular vascular diseases by intravitreal injection of anti-VEGF agents. It can lead to better policy-making and evidence-based clinical decision by ophthalmologists and optimal evidence based eye care for patients. © 2018 Journal of Ophthalmic and Vision Research

Intravitreal injection of anti-vascular endothelial growth factor agents for ocular vascular diseases: Clinical practice guideline

Purpose: To provide the clinical recommendations for the administration of intravitreal anti-vascular endothelial growth factor (VEGF) drugs especially bavacizumab for ocular vascular diseases including diabetic macular edema, neovascular age-related macular degeneration, myopic choroidal neovascularization, retinal vein occlusion and central serous chorioretinopathy. Methods: Twenty clinical questions were developed by the guideline technical committee. Relevant websites and databases were searched to find out the pertinent clinical practice guidelines to answer the questions. The technical committee provided possible answers (scenarios) according to the available evidences for each question. All scenarios along with their levels of evidence and the supported articles were sent to the experts for external review. If the experts did not agree on any of the scenarios for one particular clinical question, the technical committee reviewed all scenarios and their pertinent evidences and made the necessary decision. After that, the experts were asked to score them again. All confirmed scenarios were gathered as the final recommendations. Results: All the experts agreed on at least one of the scenarios. The technical committee extracted the agreed scenario for each clinical question as the final recommendation. Finally, 56 recommendations were developed for the procedure of intravitreal anti-VEGF injection and their applications in the management of ocular vascular diseases. Conclusion: The implementation of this guideline can standardize the management of the common ocular vascular diseases by intravitreal injection of anti-VEGF agents. It can lead to better policy-making and evidence-based clinical decision by ophthalmologists and optimal evidence based eye care for patients. © 2018 Journal of Ophthalmic and Vision Research

Supplementary Material for: Eccentric Fixation and Good Visual Acuity in a Child with Large Traumatic Macular Hole: A Case Report

A girl of eight years old was referred to our clinic with a history of penetrating injury to her left eye six-year ago with light perception (LP) vision, and a large traumatic macular hole in her right eye. Her right eye's vision was 4/10 when she first visited our clinic. Considering the patient's one-eye status, her parents' reluctance to undergo surgery, and the possibility of spontaneous closure of traumatic macular holes, it was determined to observe the patient and evaluate her visual acuity and macular hole condition. In two years, the final BCVA (best corrected visual acuity) was 8/10 in the right eye, with infratemporal eccentric fixation in visuoscopy. In addition to evaluating and reporting this case as a traumatic macular hole, we will discuss the role of non-surgical treatment and the possibility of good visual acuity with eccentric fixation in a child with large traumatic macular hole

Safety of Intravitreal Injection of Stivant, A Biosimilar to Bevacizumab, in Rabbit Eyes

Purpose: To evaluate the safety of intravitreal injection of Stivant, a biosimilar to bevacizumab, in rabbits using electrophysiological and histological analysis. Methods: Both eyes of 41 New Zealand albino rabbits were injected with 0.1 mL (2.5 mg) of Stivant. The rabbits were scheduled to be sacrificed 1, 2, 7, 14, and 28 days after injection for histopathological evaluations. Clinical examinations and electroretinography (ERG) were performed at baseline and just before sacrificing the rabbits. Fourteen separate rabbits received a reference drug (Avastin) and were considered as the control group. Furthermore, three other rabbits received the same volume of saline (saline control group). Rabbits of both control groups were sacrificed four weeks after injection. ERG was performed 1, 2, 7, 14, and 28 days after injections. Results: No significant difference was observed in a- and b-wave amplitudes and latency after intravitreal Stivant injection between baseline and different time points. Moreover, there was no statistically significant difference in wave amplitudes and latency between the Stivant and control groups. The histology of rabbit eyes of the Stivant and control groups after intravitreal injections was not distinguishable. Conclusion: The biosimilar Stivant, up to a dose of 2.5 mg, did not appear to be toxic to the retina in albino rabbits. These results suggest that this drug could be a safe and inexpensive alternative to intravitreal bevacizumab. The efficacy of these injections was not investigated in this study and needs to be evaluated in future studies

CNV-Net: Segmentation, Classification and Activity Score Measurement of Choroidal Neovascularization (CNV) Using Optical Coherence Tomography Angiography (OCTA)

This paper aims to present an artificial intelligence-based algorithm for the automated segmentation of Choroidal Neovascularization (CNV) areas and to identify the presence or absence of CNV activity criteria (branching, peripheral arcade, dark halo, shape, loop and anastomoses) in OCTA images. Methods: This retrospective and cross-sectional study includes 130 OCTA images from 101 patients with treatment-naïve CNV. At baseline, OCTA volumes of 6 × 6 mm2 were obtained to develop an AI-based algorithm to evaluate the CNV activity based on five activity criteria, including tiny branching vessels, anastomoses and loops, peripheral arcades, and perilesional hypointense halos. The proposed algorithm comprises two steps. The first block includes the pre-processing and segmentation of CNVs in OCTA images using a modified U-Net network. The second block consists of five binary classification networks, each implemented with various models from scratch, and using transfer learning from pre-trained networks. Results: The proposed segmentation network yielded an averaged Dice coefficient of 0.86. The individual classifiers corresponding to the five activity criteria (branch, peripheral arcade, dark halo, shape, loop, and anastomoses) showed accuracies of 0.84, 0.81, 0.86, 0.85, and 0.82, respectively. The AI-based algorithm potentially allows the reliable detection and segmentation of CNV from OCTA alone, without the need for imaging with contrast agents. The evaluation of the activity criteria in CNV lesions obtains acceptable results, and this algorithm could enable the objective, repeatable assessment of CNV features

THE RESULTS OF RADIAL OPTIC NEUROTOMY FOR TREATMENT OF CENTRAL RETINAL VEIN OCCLUSION

&quot;nCentral retinal vein occlusion (CRVO) is the third most common blinding vascular retinal disorder. As there is no proven treatment for CRVO, we performed this study to evaluate the effectiveness of radial optic neurotomy (RON) on visual acuity in eyes with CRVO. This study was designed as an interventional case series. Pars plana vitrectomy with RON was performed in 18 eyes of 16 patients with ischemic CRVO with visual acuities of 20/400 or less. Postoperative and preoperative visual acuities were compared using t paired test. Mean preoperative visual acuity was 20/1000 (range, 20/1600 to 20/630). Mean follow-up time was 3.6 months (range, 1 to 9 months). Mean postoperative visual acuity was 20/400 (range, 20/1600 to 20/50) at last follow-up and the difference was significant (P &amp;lt; 0.01; t paired test). Six patients (33%) improved to 20/200 postoperatively. There were no major complications intraoperatively. Chorioretinal shunts developed in neurotomy site in 9 cases (50%) 4 to 10 weeks after procedure which were associated with faster resolving of hemorrhage and venous dilation. There were no major complications noted with this procedure but vitreous hemorrhage and iris neovascularization was observed in the early postoperative period in 2 (11%) of 18 cases. RON may improve visual acuity in eyes with CRVO. It is a technically feasible and fairly safe procedure but postoperatively it may result in some complications such as vitreous hemorrhage, iris neovascularization and retinal detachment