Vitreoretinal Interface Research Articles

Characteristics of macrophage-like cells in acute nonarteritic anterior ischemic optic neuropathy and the normal fellow eyes on en face optical coherence tomography.

To quantitatively analyze macrophage-like cells (MLCs) at the vitreoretinal interface (VRI) in acute nonarteritic anterior ischemic optic neuropathy (NAION) using en face swept-source optical coherence tomography (OCT). Twenty-five acute NAION eyes and 25 normal fellow eyes from 25 patients were included in the study. MLCs were visualized in a 3 μm 6 mm×6 mm en face OCT slab above the VRI centered on the optic nerve head (ONH). After semiautomatic binarization and quantification, we evaluated the MLC density between the two groups. We also investigated the relationship between MLC density and other OCT parameters, including the increase in peripapillary retinal nerve fiber layer (RNFL) thickness and loss of vessel density (VD) in radical peripapillary capillary (RPC). The MLC density in the affected eye of the ONH was highly correlated with that in the fellow eye (r=0.612, p=0.001). The MLC density significantly increased in acute NAION eyes (NAION vs. normal, 11.97 ± 6.66 vs. 9.31 ± 6.10 cell/mm2, p=0.028). In sectorial analysis, the increase in MLCs was mainly in the superior regions (4.13 ± 7.49 vs. 0.94 ± 5.21 cell/mm2, p=0.001). The VD of RPC decreased significantly in the affected eyes (NAION vs. normal, 37.54 ± 5.25 vs. 40.56 ± 4.25, p=0.016), and the loss of RPC was predominantly in the superior sectors and the temporal sectors when compared to the inferior sectors and the nasal sectors, respectively (superior vs. inferior, -3.54 ± 6.71 vs. -0.37 ± 8.07, p=0.004; temporal vs. nasal, -2.69 ± 8.72 vs. -1.22 ± 6.06, p=0.005). The loss of RPC and the increase in MLC density were greater in affected sector corresponding to the visual field (VF) defect. MLCs located above the VRI increased significantly in acute NAION eyes, especially in subregions corresponding to VF defect, which provides clinical evidence supporting that the inflammatory response participates in the pathological process of NAION. The magnitude of the increase in MLCs corresponds to the RPC loss in the quadrant analysis.

Retinal Macrophage-Like Cells as a Biomarker of Inflammation in Retinal Vein Occlusions.

Aim: To study the macrophage-like cells (MLC) of the inner retinal surface in eyes with retinal vein occlusions (RVO) and the association of MLC with clinical characteristics of RVO. Methods: In this retrospective cross-sectional study, the medical records and multimodal imaging data of treatment-naïve patients with unilateral RVO and no abnormalities of vitreoretinal interface electronic were reviewed and analyzed. To visualize MLC, structural projections of optical coherence tomography (OCT) angiography scans within a slab between two inner limiting membrane segmentation lines (with 0 and −9 µm offset) were evaluated. The density of MLC was calculated and compared between affected and fellow eyes of each patient with regards to OCT and clinical characteristics of RVO. Results: Thirty-six eyes (twenty-eight branch RVO and eight central RVO) of 36 patients (21 males and 15 females, mean age 48.9 ± 9.8 years) were included. The density of MLC in affected eye was statistically significantly higher than that of the fellow eye, 8.5 ± 5.5 and 4.0 ± 3.6 cells/mm2, respectively (p < 0.001). The MLC density in the affected eye had a statistically significantly correlation with that of the fellow eye (r = 0.76, p = 0.0001), but with none of the OCT and clinical characteristics of the affected eye apart from the presence of subfoveal fluid. Eyes with subfoveal fluid had a statistically significantly higher mean number of MLC than that of eyes without subfoveal fluid, 12.6 ± 6.3 and 6.9 ± 4.0 cells/mm2, respectively (p = 0.009). Conclusion: The number of MLC on the inner retinal surface increases in RVO eyes which may reflect the activation of inflammatory pathways.

Superficial and Deep Capillary Plexus Nonperfusion in Nonaccidental Injury on OCTA.

A 5-year-old Caucasian male with a history nonaccidental injury (NAI) at age 1 presented with new onset no light perception in the left eye due to a closed funnel retinal detachment. The right eye showed optic nerve pallor, peripheral vascular attenuation, and leakage. Optical coherence tomography angiography (OCTA) revealed significant parafoveal attenuation of the superficial vascular plexus, intermediate capillary plexus, and the deep capillary plexus. This correlated with inner and middle retinal layer thinning temporal to the fovea and preservation of the ellipsoid zone. The peripapillary vascular plexus was preserved. Laser photocoagulation was performed to the nonperfused peripheral retina and intravitreal bevacizumab was injected. OCTA may be used in patients with NAI to characterize macular ischemia changes. Attenuation of the superficial, intermediate, and deep capillary plexuses in our patient may represent chronic ischemic retinal changes that arise from traumatic injury to the vitreoretinal interface and inner retina in NAI.

Pars plana vitrectomy for vitreoretinal interface disorders coincident with intermediate stage age-related macular degeneration.

Currently around 67 million people in Europe are affected by some form of age-related macular degeneration (AMD). As most known types of vitreoretinal (VR) interface disorders can coexist with AMD and as we can favourably affect the former with vitreoretinal surgery, our goal was to evaluate the results of vitreoretinal interface disorder surgery with macular peeling in relation to coincident intermediate stage AMD. This was a retrospective evaluation of eyes operated with 25-gauge pars plana vitrectomy (PPV). The monitored parameters were anatomical and functional findings and, safety of the procedure. The surface of the macula was stained with trypan blue and treated (peeling) with a disposable microforceps. 10% perfluoropropane, or the air tamponade was used. Distance visual acuity was examined on the ETDRS chart, the macular finding was monitored by OCT and photodocumented. The post-operative face-down position was 3-5 days. The follow-up period was 6 months. 17 eyes (14 patients, woman 86%) mean age 74 years. The primary indications for the procedure were: idiopathic macular hole (IMD) 59%, epiretinal membrane 29% and vitreomacular traction syndrome 12%. Ophthalmoscopic and OCT findings of intermediate dry form of AMD (100%), in 24% was drusoid ablation of the pigment leaf. In all cases of IMD, primary closure occurred. Input visual acuity 0.1-0.6 improved to 0.2-0.9 at the end of the follow-up period (P<0.05). No complications during surgery or progression of AMD in the follow-up period were observed. PPV for vitreoretinal interface disorders have similar anatomical results, whether the outer part of the retina is disrupted by intermediate AMD or not. Functional results are affected by possible disruption of the RPE or the outer layers of the neuroretina by AMD. The PPV procedure has a standard security profile. It is safe and does not affect the progression of AMD in the short term.

Anatomical and functional results of vitrectomy and gas tamponade in macular hole treatment

AbstractBackground: Idiopathic macular holes (IMH) of large sizes are still challenging for vitreoretinal surgeons. Predict factors of the treatment effectiveness are little‐known.Purpose: To evaluate the effectiveness of large idiopathic macular holes surgery with 18% perfluoropropane (C3F8) gas tamponade.Methods: The retrospective study, which includes 68 eyes of 68 patients diagnosed with IMH stage 3 or stage 4 (Gass classification) between January 2015 and January 2020. Among them, there were 16 men (23.5%) and 52 women (76.5%). The mean age of patients was 66.7 ± 4.3. Morphologic parameters of the macular hole (base diameter, minimum diameter) were measured and then hole form factor (HFF) was calculated. All eyes underwent 25 gauge pars plana vitrectomy, internal limiting membrane peeling, 18% C3F8 gas tamponade and postoperative face‐down positioning for two weeks. The minimum follow‐up period was 3 months and the mean follow‐up period was 19.6 ± 11.4 months. The main outcome measures were IMH closure confirmed by spectral domain optical coherence tomography at 1 month postoperatively and visual acuity at 3 months postoperatively.Results: No intra‐ and postoperative complications were observed. The IMH were closed in 61 out of 68 eyes at one month after surgery. The anatomic closure rate was 89.7%. The mean base diameter of IMH was 1022.82 ± 292.36 μm (range: 682–2019 μm). The mean minimum diameter of IMH was 471.71 ± 138.73 (range: 258–766 μm). The mean preoperative BCDVA was 0.72 ± 0.29 logMAR and mean postoperative BCDVA at 3 months after surgery was 0.5 ± 0.33 logMAR (p = 0.063, t‐test). In 47 patients (69.1%) BCDVA improved after surgery. Mean gain in visual acuity at 3 months after operation was 0.20 ± 0.27 (ΔBCDVA, logMAR). Visual acuity worsened or remained unchanged after surgery in 21 patients (30.9%) due to postoperative vitreoretinal interface disorders (foveal thinning, retinal pigment epithelium defects, and foveal cysts). The mean HFF value was 0.77 ± 0.09. There was a statistically significant moderate positive correlation between HFF and postoperative BCDVA (r = 0.56, p = 0.03, Spearman's Rho).Conclusion: Macular hole surgery with 18% C3F8 tamponade is effective technique and is associated with high rates of IMH closure and postoperative BCVA improvement. HFF was significantly correlated with postoperative visual outcomes in cases of large IMH.

Commentary: Indistinct retinal outer layers in the walls of idiopathic full thickness macular hole - A potential predictive biomarker for surgical outcomes.

Commentary: Indistinct retinal outer layers in the walls of idiopathic full thickness macular hole - A potential predictive biomarker for surgical outcomes.

ODP246 The Content of Blood Chemokine Fractalkine in Patients with Type 2 Diabetes and Diabetic Macular Edema Depending on The Type of Glucose Lowering Therapy

Abstract Relevance. Diabetic macular edema (DME) remains one of the most widespread diabetic complications. Complications associated with DME include microglial activation, dysfunction of neurons, their dystrophy and apoptosis. One of the important modern chemokines involved in the functioning of the eye neurovascular unit is fractalkine (CX3CL1). The current literature has demonstrated a positive and significant relationship between fraktalkine aqueous humor levels and central macular thickness after intravitreal injection of aflibercept in patients with DME [Rodolfo Mastropasqua et al., 2018]. Goal. To evaluate the content of blood plasmachemokine fractalkine in patients with type 2 diabetes (T2D) and DME depending on the type of glucose lowering therapy (GLT). Material and methods. This study was conducted in 82 patients (male and female) with T2D and DME. The average age of patients was 65.25 ± 10.85 years (±SD), the average duration of diabetes was 14. 0 ± 7. 05 years(±SD), the average level of HbA1c was 8.40 ± 1.58% (±SD). The inclusion criteria in this open study were voluntary informed consent, age 18 years old and more, the presence of DME according to the classification of American Academy of Ophthalmology (2014) and non-proliferative diabetic retinopathy (DR) according to the simplified version of the ETDRS. Exclusion criteria were others endocrine diseases, acute infectious diseases, cancer, decompensation of comorbid pathology, mental disorders, proteinuria, T1D, were vitreo-retinal interface diseases, damage of the optic nerve, inflammatory eye diseases, glaucoma and mature cataracts, retinal vascular diseases. Plasma fractalkine concentration was determined by «RayBio®Human Fractalkine ELISA Kit Protocol» (USA). All patients enrolled in this study were diagnosed assessing DR using color fundus photography, fluorescein angiography, spectral optical coherence tomography and were evaluated with a comprehensive ophthalmologic examination. 43 patients received oral glucose lowering drugs (OGLD), 39– metformin plus insulin. Statistical analysis of the results of the current study included one-way ANOVA analysis. Results A study of content of blood plasma fractalkine showed its dependence from the type of GLT. So comparison of mean values of blood plasma fractalkine in patients with DME revealed the following differences: OGLD 1,81±0,09ng/ml [95%CІ 1.67 - 1,94ng/ml], insulin therapy 2,11±0,08ng/ml [95%CІ 1,98-2,23 ng/ml] (р=0,02). Discussion An increase in the concentration of fractalkine in blood plasma for a certain time can serve as an indicator of an active nonspecific inflammatory process in the neuroglia, the presence of edema and a harbinger of the death of ganglion cells and vision loss. That is why fractalkine, apparently, has a promising prognostic potential for its use in evaluating the effectiveness of treatment of DME and T2D in patients receiving various types of GLT. Conclusion In patients undergoing insulin therapy, the content of fractalkine in blood plasma is statistically significantly (p = 0. 02) higher than in patients receiving OGLD. Presentation: No date and time listed

Multimodal Retinal Imaging Findings in Two Cousins With VCAN-Related Vitreoretinopathy or Wagner Disease.

Wagner disease is a rare, nonsyndromic vitreoretinopathy caused by autosomal dominant variants in the versican (VCAN) gene. It is associated with abnormalities of the vitreoretinal interface that can lead to peripheral traction and retinal detachments, which also occur in other vitreoretinopathies such as X-linked retinoschisis (XLRS), familial exudative vitreoretinopathy (FEVR) and Stickler syndrome. There is variability in the clinical phenotype in Wagner disease potentially due to variants in VCAN gene variants. In this article, we report a family harboring the VCAN c.9265+1G>C variant and describe the clinical and retinal findings in two members. [Ophthalmic Surg Lasers Imaging Retina 2022;53:639-643.].

Wide-field swept-source OCT angiography (23 × 20mm) for detecting retinal neovascularization in eyes with proliferative diabetic retinopathy.

Xephilio OCT-S1 can capture single-acquisition 23 × 20-mm wide-field swept-source optical coherence tomography angiography (SS-OCTA) images and high-resolution images using artificial intelligence. We aimed to evaluate the ability of wide-field SS-OCTA in the detection of retinal neovascularizations (NVs) in eyes with proliferative diabetic retinopathy (PDR). This retrospective study included 64 eyes of 36 patients (age, 57 ± 10years; 10 female, 26 male) with PDR. All patients underwent a comprehensive ophthalmological examination, including fluorescein angiography (FA), as well as fovea- and disc-centered 23 × 20-mm OCTA imaging (A-scan/B-scan, 928/807). We compared and examined the number of NV sites identified using conventional methods (merging the findings from biomicroscopy/color fundus photography, FA) and the number of NV sites identified using vitreoretinal interface and superficial retinal slabs of wide-field SS-OCTA images, including the position of NVs (nasal upper, nasal lower, temporal upper, temporal lower, or disc). We identified 168 NVs (32/40/45/35/16, in the abovementioned order) using the conventional method. Fovea-centered 23 × 20-mm OCTA images revealed 162 (96%) NVs (27/39/45/35/16). This method tended to miss nasal NV. In contrast, disc-centered 23 × 20-mm OCTA images identified nearly all NVs, detecting 166 (99%) NVs (32/40/44/34/16) in total. All NVs could be visualized using two wide-field OCTA images: fovea- and disc-centered. Wide-field (23 × 20mm) SS-OCTA-especially disc-centered-using Xephilio OCT-S1 identified nearly all NVs in eyes with PDR, with a single acquisition, thereby demonstrating its potential clinical application.

Real-Time (iOCT) Guided Epiretinal Membrane Surgery Using a Novel Forceps with Laser-Ablated Microstructure Tip Surface.

Purpose: We investigated intraoperative OCT (iOCT)—guided epiretinal membrane (ERM) and internal limiting membrane (ILM) removal using a novel forceps with a laser-ablated tip surface; it was designed to help prevent indentation force, shear stress, or tractional trauma when grasping very fine membranes. Patients and Methods: This retrospective study included patients who underwent 23- and 25-gauge pars plana vitrectomy (PPV) for vitreoretinal interface disorders. ERM and ILM peeling was performed under guidance with microscope-integrated iOCT using novel ILM forceps with laser-ablated tip surfaces. These forceps were engineered to enhance friction when grasping tissue. Evaluation of ERM/ILM manipulation included postoperative slow-motion video analysis of the number of grasping attempts, initial ILM mobilization, and observed damage to retinal tissue. Results: ERM/ILM removal was successfully performed in all patients, with an average of four grasp actions to initial membrane mobilization (91%). Additional use of a diamond-dusted membrane scraper was used in two cases (9%). Mean best-recorded visual acuity (BRVA) logMAR improved from 0.5 ± 0.34 to 0.33 ± 0.36 (p = 0.05) and mean central retinal thickness (CRT) improved from 462 ± 146 µm to 359 ± 78 µm (p = 0.002). Postoperative iOCT video analysis demonstrated hyper-reflectivity of the inner retinal layers associated with retinal hemorrhage in five eyes (22%), but no grasping-related retinal breaks. Conclusions: The texturized surface on the tips of the ILM forceps were found to be helpful for mobilizing ILM edges from the retinal surface. iOCT-guided ERM surgery also allowed for improved intraoperative tissue visualization. We believe that these two technologies helped reduce both unnecessary surgical maneuvers and retinal damage.

Increased Macrophage-like Cell Density in Retinal Vein Occlusion as Characterized by en Face Optical Coherence Tomography.

Objectives: to quantitatively analyze macrophage-like cells (MLCs) at the vitreoretinal interface in retinal vein occlusion (RVO) using swept-source optical coherence tomography angiography (SS-OCTA) and en face optical coherence tomography (OCT). Methods: The study included 72 RVO patients, with 43 acute patients and 29 chronic patients. For a normal control, 64 fellow eyes were included. MLCs were visualized in a 5 μm en face OCT slab above the vitreoretinal interface centered on the fovea. After semi-automatic binarization and quantification, we evaluated the MLC count and density among groups. We also investigated the MLC density and distribution relative to retinal edema. Results: Morphological changes and congregation of MLCs appeared in RVO eyes. The MLC density of both the acute and chronic groups was significantly higher than that of the control eyes (p < 0.001). In the acute group, the MLC density of the edematous region was lower than both the non-edematous region (p < 0.001) and the whole image (p < 0.01). The MLC density in acute eyes was negatively correlated to central fovea thickness (CFT) (r = −0.352, p < 0.05). The MLC density in chronic eyes was positively correlated to CFT and mean retina thickness (MRT) (r = 0.406, p < 0.05; r = 0.412, p < 0.05, respectively). Conclusions: SS-OCTA is a viable and simple method for the characterization of MLCs at the vitreoretinal interface. A significant increase in the MLC density in both acute and chronic eyes implicates the activation and recruitment of MLCs in RVO and that the MLC density and distribution can be affected by retinal edema.

Hyperreflective Membrane at the Vitreoretinal Interface in Diabetic Macular Edema: A Finding in Ultra-High-Resolution Optical Coherence Tomography.

PurposeDetecting subtle vitreoretinal interface (VRI) findings, such as a posterior hyaloid membrane, is difficult with conventional retinal imaging. We compared ultra-high-resolution spectral domain optical coherence tomography (UHR-SD-OCT) with standard-resolution OCT (SD-OCT) for the imaging of VRI abnormalities in diabetic retinopathy (DR).MethodsThis prospective cross-sectional study included 113 consecutive patients (91 patients with diabetes and 22 healthy controls). The VRI was evaluated, and the results were compared between the conventional SD-OCT and UHR-SD-OCT images. VRI findings were also investigated before and after internal limiting membrane peeling during vitrectomy for proliferative DR.ResultsA total of 159 eyes (87.4%) of 91 patients with diabetes were analyzed. UHR-SD-OCT could detect a hyperreflective layer at the VRI, in which en face OCT showed a membrane-like structure, termed the hyperreflective membrane (HRMe). The preoperative HRMe could not be detected in all patients with proliferative DR who underwent internal limiting membrane peeling during vitrectomy. Although the HRMe did not correlate with the DR stage, eyes with diabetic macular edema (DME) (64.5%) showed a significant HRMe with UHR-SD-OCT more frequently than those without DME (35.8%) (P = 0.005).ConclusionsUHR-SD-OCT can detect the HRMe at the VRI in DR eyes, particularly in eyes with DME. The HRMe may present a thickened posterior hyaloid membrane that contributes to DME development.Translational RelevanceUHR-SD-OCT detects slight changes in the VRI in DR eyes. In the future, it may help to elucidate the mechanism of DME formation.

Clinical characteristics and risk factors of myopic retinoschisis in an elderly high myopia population.

To investigate the clinical characteristics, internal correlations and risk factors for different locations of retinoschisis (RS) in an elderly high myopia (HM) population. A total of 448 eyes (304 participants) were analysed and classified into no retinoschisis (no-RS), paravascular retinoschisis (PVRS), peripapillary retinoschisis (PPRS) and macular retinoschisis (MRS) groups. Each participant underwent comprehensive ophthalmic examinations, and posterior scleral height (PSH) was measured in swept-source optical coherence tomography images. PSH, vitreoretinal interface abnormities and myopic atrophy maculopathy (MAM) were compared among groups. Retinoschisis was found in 195 (43.5%) eyes, among which 170 (37.9%) had PVRS, 123 (27.5%) had PPRS, and 103 (23.0%) had MRS. MRS was found to be combined with PVRS in 96 of 103 (93.2%) eyes. MAM was one of the risk factors for RS (odds ratio [OR], 2.459; p= 0.005). Higher nasal PSH was the only risk factor for PVRS (OR, 9.103; p= 0.008 per 1-mm increase). Elongation of axial length (AL) (OR, 1.891; p< 0.001 per 1-mm increase), higher PSH in nasal (OR, 5.059; p= 0.009 per 1-mm increase) and temporal (OR, 13.021; p= 0.012 per 1-mm increase), epiretinal membrane (ERM; OR, 2.841; p= 0.008) and vitreomacular traction (VMT; OR, 7.335; p= 0.002) were risk factors for MRS. Paravascular retinoschisis is the most common type of RS in HM and MRS is mostly combined with PVRS. MAM is one of the risk factors for RS. In addition to longer AL and higher PSH, the presence of VMT and ERM also play an important role in the formation of MRS.

Untangling the Extracellular Matrix of Idiopathic Epiretinal Membrane: A Path Winding among Structure, Interactomics and Translational Medicine.

Idiopathic epiretinal membranes (iERMs) are fibrocellular sheets of tissue that develop at the vitreoretinal interface. The iERMs consist of cells and an extracellular matrix (ECM) formed by a complex array of structural proteins and a large number of proteins that regulate cell–matrix interaction, matrix deposition and remodelling. Many components of the ECM tend to produce a layered pattern that can influence the tractional properties of the membranes. We applied a bioinformatics approach on a list of proteins previously identified with an MS-based proteomic analysis on samples of iERM to report the interactome of some key proteins. The performed pathway analysis highlights interactions occurring among ECM molecules, their cell receptors and intra- or extracellular proteins that may play a role in matrix biology in this special context. In particular, integrin β1, cathepsin B, epidermal growth factor receptor, protein-glutamine gamma-glutamyltransferase 2 and prolow-density lipoprotein receptor-related protein 1 are key hubs in the outlined protein–protein cross-talks. A section on the biomarkers that can be found in the vitreous humor of patients affected by iERM and that can modulate matrix deposition is also presented. Finally, translational medicine in iERM treatment has been summed up taking stock of the techniques that have been proposed for pharmacologic vitreolysis.

Macrophages in close proximity to the vitreoretinal interface are potential biomarkers of inflammation during retinal vascular disease

BackgroundDiabetic retinopathy and retinal vein occlusion are vision threatening retinal vascular diseases. Current first-line therapy targets the vascular component, but many patients are treatment-resistant due to unchecked inflammation. Non-invasive inflammatory imaging biomarkers are a significant unmet clinical need for patients. Imaging of macrophage-like cells on the surface of the retina using clinical optical coherence tomography (OCT) is an emerging field. These cells are increased in patients with retinal vascular disease, and could be a potential inflammatory biomarker. However, since OCT is limited by an axial resolution of 5–10 microns, the exact location and identity of these retinal cells is currently unknown.MethodsWe performed OCT followed by confocal immunofluorescence in wild-type mice to identify macrophages within 5–10 microns of the vitreoretinal interface. Next, we used Cx3cr1CreER/+; Rosa26zsGreen/+ mice to fate map retinal surface macrophages. Using confocal immunofluorescence of retinal sections and flatmounts, we quantified IBA1+Tmem119+CD169neg microglia, IBA1+Tmem119negCD169neg perivascular macrophages, and IBA1+Tmem119negCD169+ vitreal hyalocytes. Finally, we modeled neuroinflammation with CCL2 treatment and characterized retinal surface macrophages using flow cytometry, OCT, and confocal immunofluorescence.ResultsWe were able to detect IBA1+ macrophages within 5–10 microns of the vitreoretinal interface in wild-type mice using OCT followed by confirmatory confocal immunofluorescence. Retinal surface macrophages were 83.5% GFP+ at Week 1 and 82.4% GFP+ at Week 4 using fate mapping mice. At steady state, these macrophages included 82% IBA1+Tmem119+CD169neg microglia, 9% IBA1+Tmem119negCD169+ vitreal hyalocytes, and 9% IBA1+Tmem119negCD169neg perivascular macrophages. After CCL2-driven neuroinflammation, many Ly6C+ cells were detectable on the retinal surface using OCT followed by confocal immunofluorescence.ConclusionsMacrophages within close proximity to the vitreoretinal interface are self-renewing cells, and predominantly microglia with minor populations of perivascular macrophages and vitreal hyalocytes at steady state. In the context of neuroinflammation, monocytes and monocyte-derived macrophages are a significant component of retinal surface macrophages. Human OCT-based imaging of retinal surface macrophages is a potential biomarker for inflammation during retinal vascular disease.

Choroidal vascularity index changes with phacovitrectomy for vitreoretinal interface disorders.

Vitreomacular interface disorders have long been argued to change choroidal structure. The aim of this study was to determine the choroidal vascularity index (CVI) changes following internal limiting membrane peeling for epiretinal membrane (ERM) and full thickness macular hole (FTMH). Fifty-nine patients with unilateral ERM and 56 with unilateral FTMH were included in the study. Axial length, pre- and post-surgery intraocular pressure, baseline and post-phacovitrectomy CVI were calculated and compared with the normal fellow eyes. To compare the baseline and the final measurements, Wilcoxon test was used. Mann-Whitney U test was used for independent data comparisons. Median and standard deviations were compared. Axial length, pre- and post-surgery intraocular pressure differences were insignificant between study and fellow eyes within all groups. CVI were significantly lower in post-vitrectomy study eyes of all groups compared with pre-surgery (P < 0.001). There were no significant changes before and after the surgeries in fellow eyes. Baseline CVI of ERM study eyes (median 65.90%) and FTHM study eyes (median 65.59%) did not differ significantly between groups (U = 1336, P = 0.07, r = 0.16). There are conflicting results of vitreoretinal interface disorders CVI in the literature. In this study, both FTMH and ERM eyes showed reduced CVI postoperatively compared with the baseline. Preoperatively, there were no difference between study eyes and the fellow eyes.

A novel, versatile cannula for vitreoretinal surgery: Bapaye aspiration scraper - Initial experience.

The induction of posterior vitreous detachment (PVD) is an important step in the successful outcome of vitreoretinal surgery for various indications. This may pose a significant challenge intraoperatively in cases of strong adhesion between the posterior hyaloid and retina. Various techniques to achieve intraoperative PVD have been described which involve active aspiration as well as non-aspiration techniques to achieve a plane of separation between the posterior hyaloid and retina. Very frequently, combinations of these techniques might be necessary to achieve successful PVD induction. We describe a novel instrument that combines aspiration as well as non-aspiration techniques for PVD induction, Bapaye aspiration scraper. It is also useful in various vitreoretinal interface procedures due to its design and is compatible with small-gauge vitrectomy systems which are commonly used in modern vitreoretinal surgery.

Macrophage-like cells are still detectable on the retinal surface after posterior vitreous detachment

The identity of vitreoretinal interface macrophage-like cells (MLCs) remains unknown and potential candidates include retinal microglia, perivascular macrophages, monocyte-derived macrophages, and/or vitreal hyalocytes. Since hyalocytes are detectable on the posterior vitreous surface after vitreous extraction in animals, we imaged patients with and without posterior vitreous detachment (PVD) to determine if hyalocytes are the principal MLC component. We performed repeated foveal-centered 3 × 3 mm OCT-A images from 21 eyes (11 no PVD and 10 PVD eyes). Images were registered, segmented, and averaged. The OCT slab from 0 to 3 microns above the internal limiting membrane was used to detect MLCs. We calculated MLC density and distribution in relation to the superficial vascular plexus for 3 vascular regions—on vessels, perivascular, and non-vascular. MLC density was 1.8-fold greater in the PVD group compared to the no PVD group (P = 0.04). MLCs in eyes with PVD were increased 1.9-fold on-vessel (P = 0.07), 1.9-fold in the perivascular region (P = 0.12), and 2.2-fold in non-vascular areas (P = 0.22). MLC density was not severely reduced after PVD, suggesting that the majority of MLCs are not vitreal hyalocytes. PVD status is an important parameter in future MLC studies.

Correlation of collagen fibril properties and inner limiting membrane thickness with vitreoretinal adhesion in human eyes

Vitreoretinal adhesive strength is thought to play a mechanical role in various retinal diseases; however, collagen fibril properties and inner limiting membrane (ILM) thickness have not been quantitatively correlated to adhesive strength. In this work, we quantified the relationship between collagen fibril density, angle, length, and ILM thickness with vitreoretinal adhesive strength to advance our understanding of structure-function relationships in vitreoretinal adhesion. Following mechanical peel tests, human retinal sections from the equator and posterior pole of donors 42-89 years of age were extracted and processed for transmission electron microscopy. Collagen fibrils at the vitreoretinal interface were segmented and fibril density, angle, length, and ILM thickness quantified. Morphological measurements were correlated with vitreoretinal adhesion measured in the same location. We found that collagen fibril density was 1.6 times greater in the equator compared to the posterior pole across all ages (p=0.0305). Steady-state peel force showed a slight positive correlation with increasing density in both the equator and posterior pole, but was only statistically significant in the equator (p<0.05). Collagen fibril angle and length did not significantly vary with age or region. ILM thickness was 3.8 times thicker in the posterior pole compared to the equator (p<0.0001). ILM thickness was 1.8 times greater in eyes ≤60 years of age compared to eyes >60 of age (p=0.0136). Maximum peel force was significantly correlated with increasing ILM thickness in the equator (p=0.015). A similar trend was seen in the posterior pole, but this was not significant. These data suggest that collagen contributes to adhesion at the vitreoretinal interface, but the structure of the ILM is more influential on the initiation of separation between the vitreous and retina.

A Pixel-Based Machine-Learning Model For Three-Dimensional Reconstruction of Vitreous Anatomy.

PurposeTo develop a machine-learning image processing model for three-dimensional (3D) reconstruction of vitreous anatomy visualized with swept-source optical coherence tomography (SS-OCT).MethodsHealthy subjects were imaged with SS-OCT. Scans of sufficient quality were transferred into the Fiji is just ImageJ image processing toolkit, and proportions of the resulting stacks were adjusted to form cubic voxels. Image-averaging and Trainable Weka Segmentation using Sobel and variance edge detection and directional membrane projections filters were used to enhance and interpret the signals from vitreous gel, liquid spaces within the vitreous, and interfaces between the former. Two classes were defined: “Septa” and “Other.” Pixels were selected and added to each class to train the classifier. Results were generated as a probability map. Thresholding was performed to remove pixels that were classified with low confidence. Volume rendering was performed with TomViz.ResultsForty-seven eyes of 34 healthy subjects were imaged with SS-OCT. Thirty-four cube scans from 25 subjects were of sufficient quality for volume rendering. Clinically relevant vitreous features including the premacular bursa, area of Martegiani, and prevascular vitreous fissures and cisterns, as well as varying degrees of vitreous degeneration were visualized in 3D.ConclusionsA machine-learning model for 3D vitreous reconstruction of SS-OCT cube scans was developed. The resultant high-resolution 3D movies illustrated vitreous anatomy in a manner like triamcinolone-assisted vitrectomy or postmortem dye injection.Translational RelevanceThis machine learning model now allows for comprehensive examination of the vitreous structure beyond the vitreoretinal interface in 3D with potential applications for common disease states such as the vitreomacular traction and Macular Hole spectrum of diseases or proliferative diabetic retinopathy.