Prevalence of Neurological Symptoms and Imaging Findings in Von Hippel-Lindau Patients Referred to Rasool Akram Hospital, 2018-2021.

This study aimed to assess the prevalence of neurological symptoms and related imaging findings in patients with von Hippel-Lindau (VHL) at Rasool Akram Hospital from September 2018 to September 2021. This analytical observational study examined eligible patients over the period from September 2018 to September 2021. We collected demographic information (age, gender) along with imaging findings and results of neurological and eye examinations. Comparison between qualitative variables was also done using the Chi-square test or Fisher's exact test. Also, an independent t-test was used to compare quantitative variables between the two groups. SPSS version 22 software was used for statistical analysis of data. A significant level was considered less than or equal to 0.05. Of the 54 examined patients (48.1% were male and 51.9% were female) with an average age of 36.42 ± 13.37 years. A significant majority (87.0%) reported a positive family history of the disease. The most common type of disease was Type 1 observed in 94.4% of cases and Type 2A was the next most frequent (3.7%). The most common pattern of retinal pathological lesions seen in the examination was related to bilateral lesions (79.6%). The most common pathological finding was related to the presence of a mass in cerebellar magnetic resonance imaging (48.1%). Considering the findings of the present study, which highlight a significant frequency of bilateral retinal lesions as well as masses in the central nervous system and endocrine system, it is evident that patients require careful follow-up and various interventions after being diagnosed with the disease. This approach is essential to manage and potentially mitigate the complications associated with these conditions.

Clinical predictive factors and imaging biomarkers of treatment response to half dose PDT in patients with chronic central serous chorioretinopathy.

PURPOSE: To determine the clinical and imaging biomarkers of the response to half-dose photodynamic therapy (HD-PDT) in patients with central serous chorioretinopathy (CSC) METHODS: Clinical records and baseline ophthalmic images of 67 chronic CSC patients who underwent HD-PDT were assessed. In addition to demographic data, optical coherence tomography (OCT), fluorescein angiography (FA) and fundus autofluorescence (FAF) images were analyzed for specific biomarkers. The patients were categorized to early responder and late responder based on the time needed for complete resolution of subretinal fluid after PDT (less than 1 month vs. more than 1 month). The baseline clinical and imaging biomarkers were compared between the two groups. RESULTS: Seventy-three eyes of 67 patients were included in the study. The mean response time to PDT was 1.63 ± 1.48 months with 82.2 % (60/73) of patients categorized as early responder. The mean response time to PDT in delayed-response group was 4.15±1.51 months. In multivariate analysis, delayed response to PDT was associated with lacking history of systemic corticosteroid consumption, lacking history of pretreatment with eplerenone or acetazolamide before PDT and presence of hyperreflective foci in baseline OCT images (all p values < 0.05). There was no association between final visual outcome and late response to PDT. CONCLUSION: The presence of inflammatory biomarkers such as hyperreflective foci in baseline OCT images might be indicative of resistance to PDT. Moreover, the effect of pretreatment with mineralocorticoid antagonist on the response to PDT in chronic CSC should be explored in future prospective studies.

Fluorescein versus Indocyanine Green Angiography Guided Half-Dose Photodynamic Therapy for Chronic Central Serous Chorioretinopathy.

Purpose: To compare the outcomes of fluorescein angiography (FA)-guided and indocyanine green angiography (ICGA)-guided half-dose photodynamic therapy (PDT) in patients with chronic central serous chorioretinopathy (CSC). Methods: In this retrospective comparative study, medical records of eyes with chronic CSC who underwent half-dose PDT were reviewed. A retina specialist performed FA-guided half-dose PDT, and the other performed ICGA-guided treatment. The success of applying PDT in the resolution of subretinal fluid was compared between the FA- and ICGA-guided methods. Results: Eighty-two eyes of 73 patients (41 eyes in each group) received half-dose PDT. After half-dose PDT, a significant improvement in the best-corrected visual acuity (BCVA) was found at the time of the last follow-up in both groups (both P < 0.001), with no significant intergroup difference. Central subfield and subfoveal choroidal thicknesses decreased significantly in both groups at the last follow-up (all P < 0.05), with no significant differences between the groups. Subretinal fluid (SRF) resolved in all eyes, and no persistent SRF was detected during the follow-up period. Conclusion: FA-guided and ICG-guided half-dose PDT may have similar efficacy for the treatment of chronic CSC.

Congenital simple hamartoma of the retinal pigment epithelium: 4 cases with multimodal imaging.

BACKGROUND: Congenital simple hamartoma of the retinal pigment epithelium is often identified as an incidental finding. One important issue is the differentiation of these benign lesions from other lesions which could be potentially sight-threatening. METHODS: This study describes 4 cases of congenital simple hamartoma of the retinal pigment epithelium that were referred to a university-based hospital. Multimodal imaging including fundus photo, multicolor fundus photo, fundus autofluorescence, optical coherence tomography (OCT), OCT angiography, fluorescein angiography and multifocal electroretinogram is provided. RESULTS: The first case is a young man with an incidental finding of this lesion. The second and third cases are diabetic patients with congenital simple hamartoma of the retinal pigment epithelium and diabetic macular edema and the fourth one is a case of congenital simple hamartoma of the retinal pigment epithelium with a full-thickness macular hole. CONCLUSIONS: Differentiation of congenital simple hamartoma of the retinal pigment epithelium from other potentially sight-threatening lesions is important. Multimodal imaging can be helpful regarding this issue. Besides typical findings described in the literature, unique features in our cases include concurrent diabetic macular edema and association with a full-thickness macular hole.

Double Retina Sign: A New Optical Coherence Tomography Finding in Combined Hamartoma of the Retina and Retinal Pigment Epithelium.

Purpose: To describe a case of combined hamartoma of the retina and retinal pigment epithelium (CHRRPE) with peculiar optical coherence tomography (OCT) findings. Methods: Case report. Results: A 7-year-old girl with a history of decreased visual acuity in the left eye since early childhood presented with pigmented epiretinal membrane in favor of CHRRPE based on clinical and paraclinical findings. In OCT images, an area of retinal defect was noted, and the retina doubled up on itself near the defect (double retina sign). Conclusion: Careful examination of OCT images in patients with CHRRPE can reveal new findings.

Semi-supervised segmentation of retinoblastoma tumors in fundus images.

Retinoblastoma is a rare form of cancer that predominantly affects young children as the primary intraocular malignancy. Studies conducted in developed and some developing countries have revealed that early detection can successfully cure over 90% of children with retinoblastoma. An unusual white reflection in the pupil is the most common presenting symptom. Depending on the tumor size, shape, and location, medical experts may opt for different approaches and treatments, with the results varying significantly due to the high reliance on prior knowledge and experience. This study aims to present a model based on semi-supervised machine learning that will yield segmentation results comparable to those achieved by medical experts. First, the Gaussian mixture model is utilized to detect abnormalities in approximately 4200 fundus images. Due to the high computational cost of this process, the results of this approach are then used to train a cost-effective model for the same purpose. The proposed model demonstrated promising results in extracting highly detailed boundaries in fundus images. Using the Sørensen-Dice coefficient as the comparison metric for segmentation tasks, an average accuracy of 93% on evaluation data was achieved.

Stem Cell Therapy in Stargardt Disease: A Systematic Review.

This article aimed to review current literature on the safety and efficacy of stem cell therapy in Stargardt disease. A comprehensive literature search was performed, and two animal and eleven human clinical trials were retrieved. These studies utilized different kinds of stem cells, including human or mouse embryonic stem cells, mesenchymal stem cells, bone marrow mononuclear fraction, and autologous bone marrow-derived stem cells. In addition, different injection techniques including subretinal, intravitreal, and suprachoroidal space injections have been evaluated. Although stem cell therapy holds promise in improving visual function in patients with Stargardt disease, further investigation is needed to determine the long-term benefits, safety, and efficacy in determining the best delivery method and selecting the most appropriate stem cell type.

Synthesis and evaluation of modified lens using plasma treatment containing timolol-maleate loaded lauric acid-decorated chitosan-alginate nanoparticles for glaucoma.

Reducing intraocular pressure (IOP) with eye drops is one of the most common ways to control glaucoma. Low bioavailability and high frequency of administration in eye drops are major challenges in ocular pharmacotherapy. Contact lenses have attracted the attention of scientists in recent decades as an alternative method. In this study, with the aim of long-term drug delivery and better patient compatibility, contact lenses with surface modification and nanoparticles were used. In this study, timolol-maleate was loaded into polymeric nanoparticles made of chitosan conjugate with lauric acid and sodium alginate. Then silicon matrix was mixed with a curing agent (10:1), and the suspension of nanoparticles was added to the precursor and cured. Finally, for surface modification, the lenses were irradiated with oxygen plasma at different exposure times (30, 60, and 150 s) and soaked in different BSA concentrations (1, 3, and 5% w/v). The results showed nanoparticles with a size of 50 nm and a spherical shape were synthesized. The best surface modification of the lenses was for 5 (% w/v) albumin concentration and 150 s exposure time, which had the highest increase in hydrophilicity. Drug release from nanoparticles continued for 3 days and this amount increased to 6 days after dispersion in the modified lens matrix. The drug model and kinetic study show the Higuchi model completely supported the release profile. This study represents the novel drug delivery system to control intra-ocular pressure as a candidate platform for glaucoma treatment. Improved compatibility and drug release from the designed contact lenses would prepare new insight into the mentioned disease treatment.

Investigation of germline VHL variants in Iranian patients with retinal capillary hemangioblastoma and genotype-phenotype analysis.

BACKGROUND: Retinal capillary hemangioblastoma (RCH), while sporadic in some cases, is the most common and earliest manifestation of von Hippel-Lindau disease (VHL). This is the first report on different types of VHL variants and genotype-phenotype correlations in Iranian families with RCH. MATERIALS AND METHODS: In this prospective observational case series study, 17 families with RCH were included. PCR was performed to amplify 3 exons of VHL gene. Afterward, Sanger sequencing was performed on all PCR products. For the detection of VHL copy number variations, MLPA was used. RESULTS: Our study identified 10 different types of VHL variants. Missense mutations were the most common variants found and affected the structure of α domain of the VHL protein (pVHL). The majority of mutations (72.7%) in the patients with RCH and central nervous system hemangioblastoma (CNS-HB) were located on α domain. CONCLUSION: α domain of VHL may play a potential role in the pathogenesis of RCH. Our findings suggest that genotype-phenotype characteristics in those variants in α- domain may predispose patients to RCH with CNS-HB.

Targeted chemotherapy in retinoblastoma: A step forward from patient survival to globe survival.

BACKGROUND/ OBJECTIVES: Despite being the most common intraocular malignancy in childhood, there is a substantial disparity between developing and developed countries in terms of patient and globe survival in retinoblastoma (Rb). The current study intends to determine patient and globe survival before and after the introduction of the new targeted treatment modalities in a developing country. METHODS: Medical records of 350 patients (516 eyes) with retinoblastoma referred to a tertiary referral center for Rb in Tehran, Iran, were reviewed. In order to compare patient and globe survival before and after the availability of the new treatment modalities, including intra-arterial and intravitreal chemotherapy, the patients were divided into group 1 (2001-2007) and group 2 (2008-2018) based on the calendar period of diagnosis. RESULTS: Two-hundred-twenty-three eyes of 149 patients and 293 eyes of 201 patients were categorized into groups 1 and 2, respectively. The 5-year patient survival was 97% across the current survey, and the overall survival rate was 96% in group 1 and 99% in group 2 (P = 0.08). Overall, 50% of eyes with retinoblastoma underwent enucleation, which was the primary in 63% (116/184) of the unilateral and 30% (99/322) of the bilateral cases. Primary enucleation was significantly lower in group 2 (35%) in contrast to group 1 (50%) (P < 0.001). In addition, globe survival improved significantly in the International Classification of Retinoblastoma Groups D (17% in group 1 vs. 66% in group 2, P < 0.001) and E (1% in group 1 vs. 23% in group 2 P < 0.001) during the two timelines. In enucleated eyes, despite the increased rate of prelaminar involvement in group 2 (13% vs. 2% in group 1, P = 0.003), the rate of high-risk histopathologic findings was similar between the two groups. CONCLUSION: Similar to developed countries, the application of new targeted treatment modalities, including intra-arterial and intravitreal chemotherapy, has been associated with significantly improved globe survival in Rb patients. However, it should be noted that even with the availability of these novel treatment options, the decision for on-time enucleation should not be deferred.

Cystoid macular oedema without leakage in fluorescein angiography: a literature review.

Cystoid macular oedema (CMO), which is defined as a macular thickening and cystic changes due to accumulation of fluid, could be asymptomatic and only diagnosed using paraclinical techniques. Fluorescein angiography (FA) and optical coherence tomography (OCT) are useful in detecting CMO in clinical practice. Non-leaking CMO, also known as angiographically silent CMO, is referred to as cases of CMO without leakage in fluorescein angiography. This type of CMO has been reported in some retinal dystrophies, in cases of maculopathy as a side effect of certain drugs, and also in some systemic disorders. The exact mechanism and treatment options for this type of CMO are still not clear. This literature review aims to discuss different causes of non-leaking CMO, proposed mechanisms, and management options. Three sections including drugs, retinal dystrophies, and systemic disorders are discussed in this review.

Spotlight on Targeted Chemotherapy in Retinoblastoma: Safety, Efficacy, and Patient Outcomes.

As the most common primary intraocular malignancy of childhood, retinoblastoma (RB) has had a complex journey in its management, following a course from enucleation as the first life-saving treatment to numerous globe-salvaging therapies during the last century. Currently, this potentially lethal disease has achieved high survival rates owing to multidisciplinary management and the introduction of neoadjuvant and multimodal chemotherapy. Therefore, the goal of treatment is shifting toward conserving the globe and vision as much as possible. Up until recently, many advanced cases of RB were enucleated primarily; however, targeted chemotherapy via the ophthalmic artery and management of intraocular seeding by local administration of chemotherapeutic agents have revolutionized the globe-conserving therapies. The added benefit of avoiding systemic complications of cytotoxic drugs resulted in these methods gaining popularity, and they are becoming a main part of care in many referral centers. Initially, there were some safety concerns regarding these approaches; however, increasing experience has shown that these modalities are relatively safe procedures and many complications can be averted by changing the choice of the drug and using some prophylactic measures. It is hoped that, in the near future, with advances in early diagnosis and patient-targeted molecular therapies, as well as gene-editing techniques, the patient's vision can be saved even in advanced RB.

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.

Review: New horizons in retinoblastoma treatment: an updated review article.

Retinoblastoma (Rb) is a rare childhood intraocular malignancy with an incidence rate of approximately 9000 children per year worldwide. The management of Rb is inherently complex and depends on several factors. The orders of priorities in the treatment of Rb are saving life, globe salvage and vision salvage. Rarity and the young age at diagnosis impede conducting randomized clinical trials (RCTs) for new therapeutic options, and therefore pre-RCTs studies are needed. This review provides an overview of advances in Rb treatment options, focusing on the emergence of new small molecules to treat Rb. Articles related to the management and treatments of Rb were searched in different databases. Several studies and animal models discussing recent advances in the treatment of Rb were included to have a better grasp of the biological mechanisms of Rb. Over the years, the principles of management and treatment of Rb have changed significantly. Innovations in targeted therapies and molecular biology have led to improved patient and ocular survival. However, there is still a need for further evaluation of the long-term effects of these new treatments.

Ruthenium-106 plaque radiotherapy for uveal melanoma: analysis of tumor dimension and location on anatomical and functional results.

BACKGROUND: To report the long-term outcomes of Ru-106 plaque radiotherapy in eyes with uveal melanoma (UM) and to assess the effect of tumor thickness and location on final outcomes. METHODS: Medical records of 234 patients undergoing Ru-106 plaque radiotherapy for UM were reviewed, and the visual outcome, globe preservation, and patient survival were evaluated. The results of 2 groups were compared: 1. between thin (small and medium-sized, thickness < 7 mm, 148 eyes [63.2%]) and thick (thickness ≥ 7 mm, 86 eyes [36.8%]) tumors, and 2. between large (largest basal diameter [LBD] > 12 mm, 109 eyes [46.6%]) and medium/small (LBD ≤ 12 mm, 125 eyes [53.4%]). In addition, a comparison of the juxtapapillary location in 46 eyes (19.7%) versus tumors arising elsewhere and between tumors with and without ciliary involvement in 48 eyes (21.5%) were done. RESULTS: The patients were followed for a median of 54.2 months (range: 6-194.5 months). After adjusting for baseline visual acuity (VA), there was no significant association between final VA and different dimension and tumor location groups. Final globe preservation was 91.9%, and there was no significant difference between different dimension- and ciliary body involvement groups regarding anatomical success rate. The juxtapapillary tumors had lower globe preservation (80.4% vs .94.7%, p = 0.002). The hazard ratio (HR) for enucleation in juxtapapillary tumors was HR = 6.58 (95-CI: 3.84 to 11.21). The overall metastasis rate was 6.8%, with no significant difference in juxtapapillary tumors (4.3% vs.7.4%, p = 0.455). CONCLUSIONS: Ru-106 plaque radiotherapy is an effective treatment for thick and large UM. With this type of treatment, the globe preservation rate is lower in juxtapapillary tumors, but there is no significant difference in the metastasis rate.

Human-induced pluripotent stem cells-derived retinal pigmented epithelium, a new horizon for cells-based therapies for age-related macular degeneration.

Retinal pigment epithelium (RPE) degeneration is the hallmark of age-related macular degeneration (AMD). AMD, as one of the most common causes of irreversible visual impairment worldwide, remains in need of an appropriate approach to restore retinal function. Wet AMD, which is characterized by neovascular formation, can be stabilized by currently available therapies, including laser photocoagulation, photodynamic therapy, and intraocular injections of anti-VEFG (anti-vascular endothelial growth factor) therapy or a combination of these modalities. Unlike wet AMD, there is no effective therapy for progressive dry (non-neovascular) AMD. However, stem cell-based therapies, a part of regenerative medicine, have shown promising results for retinal degenerative diseases such as AMD. The goal of RPE cell therapy is to return the normal structure and function of the retina by re-establishing its interaction with photoreceptors, which is essential to vision. Considering the limited source of naturally occurring RPE cells, recent progress in stem cell research has allowed the generation of RPE cells from human pluripotent cells, both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSC). Since iPSCs face neither ethical arguments nor significant immunological considerations when compared to ESCs, they open a new horizon for cell therapy of AMD. The current study aims to discuss AMD, review the protocols for making human iPSCs-derived RPEs, and summarize recent developments in the field of iPSC-derived RPEs cell therapy.

Association of RB1 rs9568036 and CDKN1A rs1801270 Polymorphisms with Retinoblastoma Susceptibility.

Purpose: To investigate the association of polymorphisms (rs9568036 and rs1801270) in the RB1 and P21 genes with susceptibility to retinoblastoma (RB). Methods: This case-control study was designed with 50 patients with RB and 50 controls. Polymerase chain reaction was performed to amplify the intron 17 of RB1 rs9568036 and exon 2 of P21 rs1801270. Then, all the amplified fragments were subjected to directional sequencing, and finally, the association between genotypes and the development of RB risk and invasion was studied. Results: A statistically significant difference in genotypic or allele frequencies of single-nucleotide polymorphisms (SNPs) (rs1801270 and rs9568036) was found between Iranian RB patients and the controls (P > 0.05). However, the frequency of genotype RB1 rs9568036 observed a statically significant difference in the RB patients compared to the control group, and the nonwild-type allele A increased the chance of susceptibility to developing RB by 2.92 times. Conclusion: The rs9568036 SNP in the RB1 gene may increase susceptibility to the development of RB in the affected patients. In spite of that, this polymorphism does not influence RB patient's invasion. Further investigation with a large enough sample size is recommended to validate this hypothesis.

Short-term changes of cornea and tear film after ruthenium-106 plaque therapy for intraocular tumors.

PURPOSE: Plaque therapy is a well-recognized treatment for intraocular tumors. In current study, we aimed to prospectively investigate the short-term effects of ruthenium 106 (Ru-106) plaque therapy on the cornea and ocular surface parameters. METHODS: Twenty-five patients diagnosed with choroidal melanoma which undergone Ru-106 plaque therapy from 2016 to 2018 were included. Tear osmolarity, tear film break-up time, Schirmer test I, fluorescein dye staining based on Oxford staining method; Ocular Surface Disease Index (OSDI) questionnaire and corneal specular microscopy were performed. These tests were assessed preoperatively and then 3 months postoperatively. RESULTS: The mean (±SD) age of subjects was 48.52 ± 15.18 years. The patients were followed for a mean(±SD) period of 3.64 ± 2.40 months. Total mean (+SD) delivered radiation dose to the tumor apex and total received radiation by the sclera was 83.20 ± 26.31 and 640.65 ± 472.69 Gray (Gy), respectively. In longitudinal analysis, OSDI score and Oxford staining score increased significantly (P = 0.002 for both variables) and the prevalence of dry eye disease (DED) increased from 20% preoperatively to 72% at 3 months postoperatively (P = 0.001).The changes in the all specular microscopy parameters were statistically nonsignificant (all P values > 0.05). CONCLUSION: There is a considerable increase in the rate of DED following plaque therapy for the treatment of choroidal melanoma in short-term follow-up. The OSDI questionnaire and fluorescein staining test are valuable tools for early detection of DED postoperatively.

The Impacts of Episcleral Plaque Brachytherapy on Ocular Motility.

Background: To investigate the effect of various factors on ocular motility disturbance after episcleral plaque brachytherapy with Ruthenium 106 (106Ru).Methods: Twenty consecutive patients who underwent plaque brachytherapy for all types of intraocular tumors were included in this interventional prospective case series. Ruthenium-106 was used with a mean total dose of 93.2 ± 21.2 Gy toward the tumor apex. Full orthoptic examinations were performed before and after the surgery.Results: The average follow-up time was 6 months (range: 4-9 months). Two (10%) out of 20 patients developed exotropia. The mean age of patients without strabismus was higher than the patients with strabismus (49.8 ± 10.7 years compared to 23 ± 4.2 years, respectively) (p = .011). Strabismus was observed in the patients who had tumors with larger apical diameters (7.6 ± 2 mm compared to 4.1 ± 0.9 mm, respectively) (p = .021). The mean radiation dose to the tumor base in the group with strabismus was higher than the group without motility disturbance (1046.5 ± 604.1 Gy compared to 384.3 ± 175.3, respectively) (p = .021). Most tumors were located in the inferotemporal fundus (30%), followed by supratemporal location (25%), supranasal (10%), and macular region (10%). A higher percentage of patients with postoperative strabismus underwent muscle manipulation compared to the patients who did not develop this complication (100% compared to 38.9%).Conclusion: Manipulation of the extraocular muscles, high doses of radiation, and low vision could cause strabismus after episcleral plaque brachytherapy.

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.