RETINAL AND VITREOUS CHANGES ASSOCIATED WITH SPONTANEOUS IMPROVEMENT IN MYOPIC MACULAR SCHISIS.

PURPOSE: To describe the retinal and vitreous changes in eyes showing myopic macular schisis (MMS) improvement when vitrectomy was not performed and identify triggering factors. DESIGN: Retrospective observational study. SUBJECTS: Patients with non-operated myopic macular schisis METHODS: The records of patients with MMS who were followed without performing surgery for more than 6 months were retrospectively reviewed, and the eyes showing an anatomical improvement were included. MMS evolution was analyzed quantitatively (central foveal thickness [CFT], parafoveal thickness, maximum height) and qualitatively (presence/absence of foveal detachment, lamellar hole, epiretinal membrane, choroidal neovascularization, inner and outer retinoschisis, vitreous status) at baseline and at the final visit. An anatomical improvement was defined as a decrease in CFT by at least 50 µm. MAIN OUTCOME MEASURE: The rate anatomical improvement of MMS without performing vitrectomy and the morphological changes observed in these cases. RESULTS: In a cohort of 74 non-operated eyes with MMS, MMS improved in 14 eyes (19%) after a mean follow-up of 55 ± 38 months (range: 8-138). In these improved cases, the mean decrease in CFT was 153 ± 166 µm (range: 24-635, p=0.005) and a complete resolution of MMS was observed in 9 eyes (64%). In 9 eyes (64%), the improvement was associated with visible vitreous changes in the macular area on the OCT scans. The mean visual acuity, which was already good at baseline (20/50, 0.4 ± 0.2 LogMAR), increased at the last visit (20/40, 0.3 ± 0.3 LogMAR) but without reaching significance. CONCLUSION: This long-term follow-up analysis showed that almost 20% of MMS in eyes without indication for surgery could improve over time. In most cases, the improvement was associated with an apparent resolution of vitreous tensions.

[Macular hole: Differential diagnosis, treatment options and new guideline recommendations]. / Makulaforamen: Differenzialdiagnose, Behandlungsoptionen und neue Leitlinienempfehlungen.

Full-thickness macular holes (FTMH) usually result in a pronounced reduction of visual acuity and represent one of the most frequent indications for retinal surgery. If diagnosed and treatment is initiated at an early stage, surgery has a high success rate with respect to both hole closure and improvement of visual acuity. Optical coherence tomography (OCT)-based staging and sizing enables an estimation of the surgical outcome. The differential diagnostic distinction from clinically similar disorders, such as lamellar macular holes, macular pseudoholes, and foveoschisis is clinically relevant as the pathogenesis, prognosis and treatment are significantly different. While vitrectomy with peeling of the inner limiting membrane (ILM) and gas tamponade is established as the standard treatment for FTMH, some aspects of treatment are handled differently between surgeons, such as the timing of surgery, the choice of endotamponade and the type and duration of postoperative positioning. For FTMH associated with vitreomacular traction, alternative treatment options in addition to vitrectomy include intravitreal ocriplasmin injection and pneumatic vitreolysis. The current clinical guidelines of the German ophthalmological societies summarize the evidence-based recommendations for diagnosis and treatment of FTMH.

[Vitreomacular traction: diagnostics, natural course, treatment decision and guideline recommendations]. / Vitreomakuläre Traktion: Diagnostik, natürlicher Verlauf, Therapieentscheidung und Leitlinienempfehlungen.

Vitreomacular traction is a tractive foveolar adhesion of the posterior vitreous limiting membrane, resulting in pathological structural alterations of the vitreomacular interface. This must be differentiated from physiological vitreomacular adhesion, which exhibits a completely preserved foveolar depression. Symptoms depend on the severity of the macular changes and typically include reduced visual acuity, reading problems and metamorphopsia. High-resolution spectral domain optical coherence tomography (SDOCT) imaging enables classification of the sometimes only subtle morphological changes. If pronounced vitreomacular traction is accompanied by epiretinal gliosis and alterations to the outer retina, it is referred to as a vitreomacular traction syndrome. Vitreomacular traction has a high probability of spontaneous resolution within 12 months. Therefore, treatment should only be carried out in cases of undue suffering of the patient and with symptoms during bilateral vision and a lack of spontaneous resolution. In addition to pars plana vitrectomy, alternative treatment options, such as intravitreal injection of ocriplasmin and pneumatic vitreolysis are discussed for vitreomacular traction with an associated macular hole; however, ocriplasmin is no longer available in Germany. The best anatomical results in comparative investigations were achieved by vitrectomy. Pneumatic vitreolysis is controversially discussed due to the increased risk of retinal tears. In one of the current S1 guidelines of the German ophthalmological societies evidence-based recommendations for the diagnostics and treatment of vitreomacular traction are summarized.

Vitreoretinal interface abnormalities in fellow eyes of patients with a macular hole.

Objectives: This study aimed to determine the incidence of bilateral macular holes (MHs), and to investigate the incidence and characteristics of retinal abnormalities in the fellow eyes, using high-definition optical coherence tomography (OCT). Methods: Medical records from 724 consecutive patients diagnosed with full-thickness MHs, who underwent surgery at Fujita Health University Hospital from May 2015 to March 2022, were retrospectively reviewed. Based on the exclusion criteria, 658 patients with idiopathic MHs were included. B-scan OCT images of the fellow eyes were used to identify vitreoretinal interface abnormalities, such as MHs, epiretinal membranes (ERMs), vitreomacular traction syndrome (VMTS) and lamellar macular holes (LMHs). Results: The mean age of the patients was 65.9±9.0 years. There were 292 males (44.4%) and 366 females (55.6%). There were 39 fellow eyes with MHs (5.9%), 77 with ERMs (11.7%), 32 with VMTS (4.9%) and 11 with LMHs (1.7%). Thirty-four fellow eyes (5.2%) could not be classified and 469 fellow eyes were normal (71.3%). Furthermore, the 39 bilateral MHs were divided into four stages according to the Gass classification, as follows: stage 1, 32 eyes (82.1%); stage 2, none (0%); stage 3, 5 eyes (12.8%); and stage 4, 2 eyes (5.1%). Conclusions: Vitreoretinal interface abnormalities, such as MHs, ERMs, VMTS and LMHs, are more common in the fellow eyes of patients with MHs than in the healthy population. The fellow eyes of patients with MHs should be carefully followed using OCT.

Hyalocytes-guardians of the vitreoretinal interface.

Originally discovered in the nineteenth century, hyalocytes are the resident macrophage cell population in the vitreous body. Despite this, a comprehensive understanding of their precise function and immunological significance has only recently emerged. In this article, we summarize recent in-depth investigations deciphering the critical role of hyalocytes in various aspects of vitreous physiology, such as the molecular biology and functions of hyalocytes during development, adult homeostasis, and disease. Hyalocytes are involved in fetal vitreous development, hyaloid vasculature regression, surveillance and metabolism of the vitreoretinal interface, synthesis and breakdown of vitreous components, and maintenance of vitreous transparency. While sharing certain resemblances with other myeloid cell populations such as retinal microglia, hyalocytes possess a distinct molecular signature and exhibit a gene expression profile tailored to the specific needs of their host tissue. In addition to inflammatory eye diseases such as uveitis, hyalocytes play important roles in conditions characterized by anomalous posterior vitreous detachment (PVD) and vitreoschisis. These can be hypercellular tractional vitreo-retinopathies, such as macular pucker, proliferative vitreo-retinopathy (PVR), and proliferative diabetic vitreo-retinopathy (PDVR), as well as paucicellular disorders such as vitreo-macular traction syndrome and macular holes. Notably, hyalocytes assume a significant role in the early pathophysiology of these disorders by promoting cell migration and proliferation, as well as subsequent membrane contraction, and vitreoretinal traction. Thus, early intervention targeting hyalocytes could potentially mitigate disease progression and prevent the development of proliferative vitreoretinal disorders altogether, by eliminating the involvement of vitreous and hyalocytes.

Macular hole surgery follow-up with spectral domain-optical coherence tomography-guided facedown posturing.

PURPOSE: The main treatment for macular hole (MH) is pars plana vitrectomy, with or without internal limiting membrane (ILM) peeling, followed by gas tamponade and face-down positioning (FDP). This study aims to present the anatomical and visual outcomes following MH repair with optical coherence tomography (OCT)-guided FDP. METHODS: Thirty-two patients who underwent surgery for idiopathic MH were enrolled. The requirement for the prone position was lifted for those with MH closure observed under gas on postoperative day one OCT. Patients with unclosed MHs were instructed to maintain FDP until the 3rd day. Best-corrected visual acuity at preoperative, postoperative 1st month, and the last visit, closure time post-surgery, duration of prone position, and surgical success rate were recorded. RESULTS: Among the patients, 21 underwent phacovitrectomy + ILM peeling + gas tamponade, while 11 had vitrectomy + ILM peeling + gas tamponade. On postoperative day one, 28 out of 32 MHs closed, with 3 closures on day 3 and one on day 5. There were 18 stage two (56.3%), 13 stage three (40.6%) and 1 stage four (3.1%) MHs. The mean minimum MH diameter was 381.75 ± 68.07 (min 260-max 517) microns. All patients with MH closure time over postoperative day one had non-combined vitrectomy instead of phacovitrectomy. No late complications were observed. CONCLUSIONS: OCT-guided FDP approach yields excellent closure rates with no late complications and ensures good patient comfort.

[Selective vital dyes in macular surgery : Do they increase the probability of intraoperative identification of the internal limiting membrane also for an experienced surgeon?] / Selektive Vitalfarbstoffe in der Makulachirurgie : Erhöhen sie die Wahrscheinlichkeit der intraoperativen ILM-Identifizierung auch bei einem erfahrenen Operateur?

BACKGROUND: Various vital dyes exist on the market for intraoperative internal limiting membrane (ILM) identification. The aim of this study was to verify the added value of these dyes for ILM identification and in the difficulty of ILM peeling during pars plana vitrectomy (ppV) by a single surgeon highly experienced in this operation. MATERIAL AND METHODS: In this study 400 ppV surgical reports involving ILM peeling were retrospectively analyzed. Intraoperative assessment of identification or difficulty of intraoperative ILM peeling had to be documented in the surgical report. The total group consisted of 2 cohorts each with 200 surgical reports (first cohort without selective vital dyes, period 2004-2006; second cohort with vital dyes in the majority of ppVs, period 2013-2020). RESULTS: The difference between both groups in terms of intraoperative identification of ILM was statistically significant (p < 0.001); however, no statistically significant difference (p = 0.951) was found between the two groups in terms of difficulty of ILM peeling. In logistic regression analysis neither patient gender, age, eye side, lens status nor posterior vitreous limiting membrane status were significantly associated with ILM identification. CONCLUSION: The introduction of intravital dyes represents a decisive advancement in retinal surgery. In the investigated sample this benefit was evident from two precisely defined surgical cohorts of a single highly experienced surgeon. This underlines the additional benefit of using selective vital dyes to identify ILM in macular surgery for less experienced surgeons.

Accuracy of biomicroscopy, ultrasonography and spectral-domain OCT in detection of complete posterior vitreous detachment.

BACKGROUND: To evaluate the accuracy of preoperative biomicroscopy (BM), ultrasonography (US), and spectral domain optical coherence tomography (SD-OCT) to determine complete posterior vitreous detachment (PVD) confirmed by intraoperative findings of triamcinolone acetonide-assisted pars plana vitrectomy (PPV). METHODS: This prospective study included all consecutive patients admitted for surgical treatment of the epiretinal membrane (ERM) and macular hole (MH). The presence of complete PVD was determined one day before PPV using BM, US, SD-OCT. The preoperative findings were compared to the PVD status determined during PPV. RESULTS: A total of 123 eyes from 123 patients were included in the study. Indications for PPV included ERM in 57 (46.3%), full thickness macular hole in 57 (46.3%) and lamellar macular hole in 9 (7.3%) patients. Complete PVD during PPV was observed in 18 (31.6%; 95%CI:18.7-49.9) patients with ERM and 13 (19.7%; 95%CI:10.4-33.7) patients with MH. The sensitivity of preoperative BM, US, SD-OCT was 48.4% (95%CI:30.2-66.9), 61.3% (95%CI:42.2-78.2) and 54.8% (95%CI:36.0-72.7) respectively. The specificity of preoperative BM, US, SD-OCT was 81.5% (95%CI:72.1-88.9), 90.2% (95%CI:82.2-95.4) and 85.9% (95%CI:77.0-92.3) respectively. With a prevalence of 25.2% of PVD in our sample the positive predictive value of preoperative BM, US, SD-OCT was 46.9% (95%CI:29.1-65.3), 67.9% (95%CI:47.6-84.1) and 56.7% (95%CI:37.4-74.5) respectively. CONCLUSION: Preoperative BM, US, and SD-OCT showed relatively low sensitivity but also good specificity in assessing complete PVD. A combination of all three diagnostic methods can provide a good assessment of the vitreoretinal interface state.

[Role of vitreous in the pathogenesis of neovascular age-related macular degeneration]. / Die Rolle des Glaskörpers in der Pathogenese der exsudativen altersabhängigen Makuladegeneration.

Age-related changes in vitreous molecular and anatomic morphology begin early in life and involve two major processes: vitreous liquefaction and weakening of vitreo-retinal adhesion. An imbalance in these two processes results in anomalous posterior vitreous detachment (PVD), which comprises, among other conditions, vitreo-macular adhesion (VMA) and traction (VMT). VMA is more common in patients with neovascular age-related macular degeneration (nAMD) than age-matched control patients, with the site of posterior vitreous adherence to the inner retina correlating with location of neovascular complexes. The pernicious effects of an attached posterior vitreous on age-related macular degeneration (AMD) progression involve mechanical forces, enhanced fluid influx and inflammation in and between the retinal layers, hypoxia leading to an accumulation of vascular endothelial growth factor (VEGF) and other stimulatory cytokines, and probably an infiltration of hyalocytes. It has been shown that vitrectomy not only mitigates progression to end-stage AMD, but existing choroidal neovascularization regresses after surgery. Thus, surgical PVD induction during vitrectomy or by pharmacologic vitreolysis may be considered in non-responders to anti-VEGF treatment with concomitant VMA.

Role of the Vitreous in Retinal Pathology: A Narrative Review.

The vitreous body is an anatomically and biochemically complex structure. Because of its proximity and firm adherence to the retina, researchers have examined the link between these two structures and how their individual pathologies might be connected. Several experimental and clinical studies have already demonstrated the important role of vitreous in the pathogenesis of retinal disorders. This narrative review highlights the role of the vitreous in retinal diseases and the improvements that have been made since the introduction of optical coherence tomography. This leads to a better understanding of vitreoretinal diseases and demonstrates its determinant role in other retinal pathologies, such as diabetic retinopathy or age-related macular degeneration. As we deepen our knowledge of the vitreous's structure, function, and abnormal conditions, we can better link the changes in diseases and identify effective treatments.

Vitreoretinal Interface Changes After Anti-vascular Endothelial Growth Factor Treatment in Highly Myopic Eyes: A Real-World Study.

INTRODUCTION: To investigate changes in the vitreoretinal interface after anti-vascular endothelial growth factor (anti-VEGF) treatment in highly myopic eyes. METHODS: Eyes with myopic choroidal neovascularization (mCNV) treated with intravitreal injection of anti-VEGF in a single-center were retrospectively reviewed. Fundus abnormalities and features of optical computed tomography were studied. RESULTS: A total of 295 eyes from 254 patients were recruited to the study. Prevalence of myopic macular retinoschisis (MRS) was 25.4%, and the rates of progression and onset of MRS were 75.9% and 16.2%, respectively. Outer retinal schisis (ß = 8.586, p = 0.003) and lamellar macular hole (LMH) (ß = 5.015, p = 0.043) at baseline were identified risk factors for progression and onset of MRS, whereas male sex (ß = 9.000, p = 0.039) and outer retinal schisis at baseline (ß = 5.250, p = 0.010) were risk factors for MRS progression. Progression of MRS was first detected in outer retinal layers in 48.3% of eyes. Thirteen eyes required surgical intervention. Spontaneous improvements of MRS were observed in five eyes (6.3%). CONCLUSION: Changes in the vitreoretinal interface, such as progression, onset, and improvement of MRS, were observed after anti-VEGF treatment. Outer retinal schisis and LMH were risk factors of progression and onset of MRS after anti-VEGF treatment. Intravitreal injection of ranibizumab and retinal hemorrhage were protective factors for surgical intervention for vision-threatening MRS.

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

BACKGROUND AND AIMS: 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. METHODOLOGY: 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. RESULTS: 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. CONCLUSION: 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.

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

PURPOSE: To investigate the clinical characteristics, internal correlations and risk factors for different locations of retinoschisis (RS) in an elderly high myopia (HM) population. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

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.

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.

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

BACKGROUND: Diabetic 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. METHODS: We 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. RESULTS: We 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. CONCLUSIONS: Macrophages 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.

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.

Exploring the Vitreoretinal Interface: A Key Instigator of Unique Retinal Hemorrhage Patterns in Pediatric Head Trauma.

PURPOSE: Various types of trauma can cause retinal hemorrhages in children, including accidental and nonaccidental head trauma. We used animal eyes and a finite element model of the eye to examine stress patterns produced during purely linear and angular accelerations, along with stresses attained during simulated repetitive shaking of an infant. METHODS: Using sheep and primate eyes, sclerotomy windows were created by removing the sclera, choroid, and retinal pigment epithelium to expose the retina. A nanofiber square was glued to a 5 mm2 area of retina. The square was pulled and separated from vitreous while force was measured. A finite element model of the pediatric eye was used to computationally measure tension stresses during shaking. RESULTS: In both sheep and primate eyes, tension stress required for separation of retina from vitreous range from 1 to 5 kPa. Tension stress generated at the vitreoretinal interface predicted by the computer simulation ranged from 3 to 16 kPa during a cycle of shaking. Linear acceleration generated lower tension stress than angular acceleration. Angular acceleration generated maximal tension stress along the retinal vasculature. Linear acceleration produced more diffuse force distribution centered at the poster pole. CONCLUSIONS: The finite element model predicted that tension stress attained at the retina during forcible shaking of an eye can exceed the minimum threshold needed to produce vitreoretinal separation as measured in animal eyes. Furthermore, the results show that movements that involve significant angular acceleration produce strong stresses localized along the vasculature, whereas linear acceleration produces weaker, more diffuse stress centered towards the posterior pole of the eye.

Vitreoretinal interface anomalies in patients with a history of toxoplasmosis retinochoroiditis.

PURPOSE: To evaluate vitreoretinal interface anomalies over time in patients diagnosed with toxoplasmosis retinochoroiditis (TRC) and progression of the chronic disease. STUDY DESIGN: Retrospective clinical study. METHODS: The clinical records of 36 patients with TRC were studied retrospectively. All patients underwent standard ophthalmological examinations and optical coherence tomography (optical coherence tomography: OCT). Vitreoretinal interface changes and retinal layers in the macula and lesion area were evaluated. RESULTS: The fovea was involved in 9 (25%) patients. OCT of the scar region showed retinal layer thinning and disorganization in all cases. Complete posterior vitreous detachment (PVD) was detected in 9 (25%) cases, incomplete PVD in 22 (61%) cases and no PVD in 5 (13.8%) cases. In 23 (63%) of the 36 patients with inactive TRC lesions, an epiretinal membrane (ERM) was detected by follow-up OCT, i.e., in 14 (60%) patients with incomplete PVD, 8 (34.7%) with complete PVD, and 1 (4%) with no PVD. Vitreoschisis was found in 5 of 22 patients with incomplete PVD; an ERM developed in 4 of these 5 patients. No ERM developed only in the macula, i.e., independent of the TRC scar region. CONCLUSIONS: Vitreoretinal interface anomalies are common in patients diagnosed with TRC, including those with incomplete PVD. We observed no progression of vitreoretinal interface anomalies during the follow-up of patients diagnosed with TRC.

Optical coherence tomography angiography for the detection and evaluation of ptic disc neovascularization: a retrospective, observational study.

BACKGROUND: To assess and characterize neovascularization of the optic disc (NVD) using optical coherence tomography angiography (OCTA) and different OCTA-based methods. METHODS: This retrospective, observational study included patients who were suspected of having early PDR with no presence of clinically apparent neovascularization (NV) bur were clinically diagnosed with proliferative diabetic retinopathy (PDR), or severe NPDR. Patients underwent standard clinical examinations and OCTA imaging using a 6 × 6 montage scan. Two trained graders identified NVD using different imaging systems (ultra-widefield-colour fundus photography (UWF-CFP), OCT, OCTA and fluorescein angiography (FA)). Moreover, morphological classification of NVD was performed. The detection and morphological classification of NVD by different OCTA-based methods (B-scan OCTA, En-face OCTA, VRI Angio and VRI Structure) were compared. RESULTS: A total of 169 eyes (126 eyes with PDR and 43 eyes with severe NPDR) of 123 participants were included in this study. The detection rate of NVD was 34.91% by UWF-CFP compared with 59.76% by OCT, 59.76% by OCTA, and 62.72% by FA. After excluding 2 cases with epiretinal membranes, the NVD diagnosis detected by OCT was used as the standard. Among 99 eyes diagnosed with NVD by OCT, B-scan OCTA detected NVD with a sensitivity of 97.98%, which was higher than that by en face OCTA (80.81%), VRI Angio (65.66%), and VRI Structure (61.62%) (all P < 0.05). According to its characteristics on OCTA, NVD was divided into four types (12 cases of type I, 6 cases of type II, 39 cases of type III, and 42 cases of type IV). For type I, B-scan OCTA exhibited a higher diagnostic sensitivity than other methods (P < 0.05). For types II and IV, there were no statistically significant differences in the sensitivity of various methods between the two groups (P > 0.05). CONCLUSION: OCTA and different OCTA-based methods are significant to the diagnosis of NVD, and the diagnostic accuracy of different detection methods may be related to different types of NVD.