Ophthalmology

Peripapillary microvasculature changes after vitrectomy in epiretinal membrane via swept-source OCT angiography

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Purpose To evaluate the peripapillary microvasculature changes in patients with epiretinal membrane (ERM) following pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling using swept-source optical coherence tomography angiography (SS-OCTA). Method Medical records and multimodal imaging data of 33 eyes after PPV for ERM were retrospectively reviewed. Peripapillary SS-OCTA images of 6×6 mm2 were recorded at at pre- and post-operatively every 6 months for 1 year. A semi-automated method was used to analyzed SS-OCTA images, excluding the optic disc area, using the MATLAB software. The peripapillary vessel density (pVD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) was quantified in four quadrants (superior, inferior, nasal and temporal). Result The mean pVD in SCP and DCP decreased at 6- and 12-months follow-up. In sectoral analysis, superior, inferior, and temporal quadrants pVD in SCP and DCP were significantly reduced at ...

Pathophysiology of outer retinal corrugations: Imaging dataset and mechanical models

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This article presents high-resolution swept-source optical coherence tomography (SS-OCT) imaging data used to elaborate a mechanical model that elucidates the formation of outer retinal corrugations (ORCs) in rhegmatogenous retinal detachments (RRD). The imaging data shared in the repository and presented in this article is related to the research paper entitled “Outer Retinal Corrugations in Rhegmatogenous Retinal Detachment: The Retinal Pigment Epithelium-Photoreceptor Dysregulation Theory” (Muni et al., AJO, 2022). The dataset consists of 69 baseline cross-sectional SS-OCT scans from 66 patients that were assessed for the presence of ORCs and analyzed considering the clinical features of each case. From the 66 cases, we selected SS-OCT images of 4 RRD patients with visible ORCs and no cystoid macular edema (CME) to validate the mechanical model. We modelled the retina as a composite material consisting of the outer retinal layer (photoreceptor layer) and the inner retinal layer...

Optical Coherence Tomography as a Predictor of Visual Protection and Recovery in the Setting of Pituitary Apoplexy

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Objective: Pituitary apoplexy is a clinical condition resulting in neurological and pituitary dysfunction as a result of pituitary tumor infarction or hemorrhage. Surgery is often recommended in the setting of acute visual loss. Preoperative RNFL thickness has previously been shown to be a prognosticator for long-term visual recovery following pituitary or parasellar tumor resection. The authors investigated if perioperative optical coherence tomography (OCT) could be used as a prognosticator of visual outcomes in pituitary apoplexy. Methods: The authors retrospectively reviewed the medical records of 41 patients who had presented to their institution with pituitary apoplexy from 2013 to 2022. Six patients were identified that had perioperative optical coherence tomography in combination with Humphrey visual fields. All patients underwent preoperative MRI demonstrating pituitary apoplexy. All six patients underwent endoscopic transsphenoidal resection of their pituitary tumor. Hu...

Analyses of Foveal Avascular Zone in Patients with General Blunt Ocular Trauma Using Optical Coherence Tomography Angiography

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Purpose To investigate the effect of blunt ocular trauma (BOT) on foveal circulation, and in particular the foveal avascular zone (FAZ), using optical coherence tomography angiography (OCTA). Methods This retrospective study consisted of 96 eyes (48 traumatized eyes and 48 nontraumatized eyes) from 48 subjects with BOT. We analyzed the FAZ area of deep capillary plexus (DCP) and superficial capillary plexus (SCP) immediately after BOT and at 2 weeks after BOT. We also evaluated the FAZ area of DCP and SCP in patients with and without blowout fracture (BOF). Results There were no significant differences in FAZ area between traumatized and nontraumatized eyes at DCP and SCP in the initial test. In traumatized eyes, the FAZ area at SCP was significantly reduced on follow-up when compared to initial test (p = 0.01). In case of eyes with BOF, there was no significant differences in FAZ area between traumatized and nontraumatized eyes at DCP and SCP on initial test. No significant di...

Optical coherence tomography-based assessment of macular vessel density, retinal layer metrics and sub-foveal choroidal thickness in COVID-19 recovered patients

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Purpose: The primary objective of the study was to assess the macular retinal vessel density, subfoveal choroidal thickness, and retinal layer metrics by optical coherence tomography angiography (OCTA), enhanced-depth imaging optical coherence tomography (EDI-OCT), and spectral domain optical coherence tomography (SD-OCT), respectively, in recovered COVID-19 patients and its comparison with the same in control subjects. The secondary objective was to evaluate differences in OCTA parameters in relation with the severity of COVID-19 disease and administration of corticosteroids. Methods: A case–control study was performed that included patients who had recovered from COVID-19 and age-matched healthy controls. Complete ocular examination including OCTA, SD-OCT, and EDI-OCT were performed three months following the diagnosis. Results: Three hundred sixty eyes of 180 subjects were enrolled between the two groups. A decreased mean foveal avascular zone area in both superficial ca...

Self Distillation for Improving the Generalizability of Retinal Disease Diagnosis using Optical Coherence Tomography Images

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Optical coherence tomography (OCT) imaging has become a point-of-care imaging modality for the diagnosis of retinal diseases. Varying speckle noise in the OCT images across datasets and scanners worsens the performance of existing artificial intelligence (deep learning) models, that have been trained mostly with images having a particular noise level. The existing deep learning models for predicting retinal diseases are heavy, requires a sophisticated computing environment to train and deploy. Generalized lightweight deep learning models that can provide an automated diagnosis on an edge platform are highly appealing in the clinic. This work proposes a self distillation framework based on lightweight deep learning models for building generalizable deep models for retinal disease diagnosis. The proposed approach with three different baseline models ResNet18, MobileNetV2 and ShuffleNetV2, has been validated on simulated and real-time noisy OCT B-scans spanning a range of SNRs from fou...

Variability of Vascular Reactivity in the Retina and Choriocapillaris to Oxygen and Carbon Dioxide Using Optical Coherence Tomography Angiography

Purpose: To investigate the regional and layer-specific vascular reactivity of the healthy human retina and choriocapillaris to changes in systemic carbon dioxide or oxygen. Methods: High-resolution 3 × 3-mm2 optical coherence tomography angiography (OCTA) images were acquired from the central macula, temporal macula, and peripapillary retina while participants were exposed to three gas breathing conditions—room air, 5%CO2, and 100% O2. OCTA from all three regions were extracted and the apparent skeletonized vessel density (VSD) was assessed. The mean flow deficit sizes (MFDSs) of the choriocapillaris were also assessed. Repeated-measures analysis of variance was used to compare the ratio of intrasubject VSD change induced by the gas conditions from baseline in the superficial retinal layer (SRL) and deep retinal layer (DRL) for each retinal region independently, as well as the MFDS of the choriocapillaris. We also compared the vessel reactivity between the retinal capillaries an...

Using Ultrawide Field-Directed Optical Coherence Tomography for Differentiating Nonproliferative and Proliferative Diabetic Retinopathy

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Purpose: To evaluate the ability of ultrawide field (UWF)–directed optical coherence tomography (OCT) to detect retinal neovascularization in eyes thought to have severe nonproliferative diabetic retinopathy (NPDR). Methods: Retrospective study of 20 consecutive patients diagnosed with severe NPDR by clinical examination. All patients underwent UWF color imaging (UWF-CI) and UWF-directed OCT following a prespecified imaging protocol to assess the mid periphery, 15/32 (46.9%) eyes underwent UWF–fluorescein angiography (FA). On OCT, new vessels elsewhere (NVE) were defined when vessels breached the internal limiting membrane. Results: A total of 32 eyes of 20 patients were evaluated. Of the 45 suspected areas of intraretinal microvascular abnormalities (IRMA) on UWF-CI, 38 (84.4%) were imaged by UWF-directed OCT, and 9/38 IRMA (23.7%) were NVE by OCT. Furthermore, UWF-directed OCT identified seven additional NVE in three eyes not seen on UWF-CI. This resulted in a change in diabet...

The retina technology of tomorrow today

The retina technology of tomorrow today Innovations such as improved visualization for pars plana vitrectomy (PPV) through optical coherence tomography (OCT) in the operating room (OR), the use of methotrexate for proliferative vitreoretinopathy (PVR) prevention, surgery for wet age-related macular degeneration, and gene therapy for inherited retinal diseases will likely be incorporated in retinal ophthalmology in the near future, according to Christopher Riemann, MD. Riemann is a vitreoretinal surgeon at the Cincinnati Eye Institute and a volunteer associate professor at the University of Cincinnati School of Medicine in Ohio. Speaking at the annual Sally Letson Symposium in Ottawa, Ontario, Canada, Riemann highlighted new applications of existing medications and technology as well as innovative developments in the next 2 years. “What do we do when the anti-VEGF drugs don’t work?” Riemann asked, pointing to examples where a patient had a submacular hemorrhage after receiving monthly anti-VEGF injections. The injection...

Assessment of choroidal structural changes in patients with pre- and early-stage clinical diabetic retinopathy using wide-field SS-OCTA

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Purpose: To investigate the micro-vascular changes in choroidal structures in patients with pre- and early-stage clinical diabetic retinopathy (DR) using wide-field Swept-Source Optical Coherence Tomography Angiography (SS-OCTA). Method: This observational cross-sectional study included 131 eyes of 68 subjects that were divided into healthy controls (group 1, n = 46), pre-DR (group 2, n = 43), early-stage DR (group 3, n = 42) cohorts. All participants that underwent SS-OCTA examination were inpatients in the department of Ophthalmology and the department of Endocrinology, Qilu Hospital, Shandong University, and Department of Ophthalmology, Aier Eye Hospital, Jinan, from July 11, 2021 to March 17, 2022. The choroidal vascularity index (CVI), choroidal thickness (ChT) and central macular thickness (CMT) in the whole area (diameter of 12 mm) and concentric rings with different ranges (0–3, 3–6, 6–9, and 9–12 mm) were recorded and analyzed from the OCTA image. Result: Compared wit...

Optical coherence tomography and Scheimpflug imaging of the iridocorneal angle following intravitreal injection of different medications: a longitudinal analysis

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Purpose Intravitreal injection of medications induces a sudden increase in posterior segment volume and pushes iris plane anteriorly to narrow iridocorneal angle. The aim of this study to follow and define longitudinal course of these changes following intravitreal injection of 3 different anti-vascular endothelial growth factor (VEGF) medications or dexamethasone implant. Materials and Methods This prospective, longitudinal study included 89 eyes of 89 patients that had an intravitreal injection of bevacizumab (n=20) or ranibizumab (n=26) or aflibercept (n=22) or dexamethasone implant (n=21). All the participants had a detailed ophthalmological examination including anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging of the iridocorneal angle, evaluation of anterior chamber depth (ACD), axial length with optical biometry and endothelial cell counts with specular microscopy just before the injection, at post-injection day 1, and post-injection 1st month...

The effect of acetazolamide on the retinal and choroidal vasculature of the macula and the optic disc using OCT angiography

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Introduction and objectives To investigate the effect of acetazolamide (AZ) on the retinal and choroidal ocular microvasculature in the macula and radial peripapillary capillaries (RPC) of the optic disc with OCT Angiography (OCTA). Materials and methods Nine-month observational cross-sectional study. Forty-five eyes from 45 healthy participants who underwent cataract surgery were recruited. Macular retina and choriocapillaris vessel density (VD) and RPC VD in the optic disc area were compared before and 60 minutes after 250 mg acetazolamide per os. Intraocular pressure (IOP) and systemic blood pressure (BP) were also measured before each scan. Results Mean age was 73.1 ± 6.9 years. VDs in the superficial (SCP) and deep (DCP) capillary plexus of the retina and the choriocapillaris (CC) in the macular area showed no significant change (p > 0.5, for all parameters). VD in the RPC showed no significant change with AZ (p > 0.5, for all parameters). Fovea...

Normal peripheral choroidal thickness measured by widefield optical coherence tomography

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Purpose:  Choroidal stasis plays important role in the pathogenesis of many conditions and leads to choroidal thickening. However, the normal peripheral choroidal thickness (CT) pattern remains unknown. This study investigated peripheral CT (PCT) and associated factors using ultra-widefield optical coherence tomography (UWF-OCT) in healthy eyes. Methods:  This cross-sectional study included 120 healthy eyes (57 males; age, 52.0 ± 20.5 years). We used CT maps created by UWF-OCT (viewing angle, 200°) with real-shape correction. The peripheral area was defined from 60° to 100, and further separated vertically and horizontally. The PCT and the correlations between PCT and subjects' characteristics were examined. Results:  The PCT (µm) were 227.1 ± 57.0, 199.6 ± 53.9, 196.6 ± 57.1, and 148.0 ± 38.2 in supratemporal (ST), infratemporal, supranasal (SN), and infranasal (IN) area, respectively. The thickest peripheral sector was most frequently observed in ST (69.2%). The...

Post-GWAS screening of candidate genes for refractive error in mutant zebrafish models

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Genome-wide association studies (GWAS) have dissected numerous genetic factors underlying refractive errors (RE) such as myopia. Despite significant insights into understanding the genetic architecture of RE, few studies have validated and explored the functional role of candidate genes within these loci. To functionally follow-up on GWAS and characterize the potential role of candidate genes on the development of RE, we prioritized nine genes (TJP2, PDE11A, SHISA6, LAMA2, LRRC4C, KCNQ5, GNB3, RBFOX1, and GRIA4) based on biological and statistical evidence; and used CRISPR/cas9 to generate knock-out zebrafish mutants. These mutant fish were screened for abnormalities in axial length by spectral-domain optical coherence tomography and refractive status by eccentric photorefraction at the juvenile (2 months) and adult (4 months) developmental stage. We found a significantly increased axial length and myopic shift in refractive status in three of our studied mutants, indicating a pot...

Optical coherence tomographic findings of glaucomatous eyes with papillomacular retinoschisis

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Objectives To investigate the topographic relationship between the shape of the optic nerve head (ONH) margin detected by optical coherence tomography (OCT) and the clinical characteristics of papillomacular retinoschisis (PMRS) in glaucomatous eyes. Methods The medical record of patients with a PMRS in a glaucomatous eye were reviewed. The eyes were placed into two groups determined by the shape of the ONH margin in the OCT images; eyes with an externally oblique ONH margin (Group 1) and the eyes with an internally oblique ONH margin (Group 2). We compared the clinical characteristics of the PMRS between these two groups. Results We studied 31 eyes of 29 patients with PMRS and glaucoma with 24 eyes in Group 1 and 7 eyes in Group 2. The optic nerve fiber layer schisis on the lamina cribosa (LC), beta zone, and gamma zone, and the LC defects were detected significantly more frequently in Group 1 than in Group 2 eyes (P < 0.05). A retinal nerve fiber schisis was observed a...

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