Vitreous substitutes and tamponades occupy the vitreous cavity following vitrectomy in the management of various conditions such as retinal detachment, macular hole, and diabetic retinopathy. Such replacements can be for the short term (gases such as sulfur hexafluoride (SF6) and perfluoropropane (C3F8) or long term (such as silicone oils). Certain substitutes such as perfluorocarbon liquids are used only transiently during surgery as \"a third hand\" or rarely till a few days post surgery. Hydrogels and hyaluronan derivatives are among the newer vitreous substitutes that are showing promise for the future, albeit still under investigation. still being investigated for use as vitreous substitutes. These materials have properties similar to the natural vitreous and may offer advantages such as improved biocompatibility and biodegradability. Although vitreous substitutes are valuable tools in treating vitreoretinal conditions, they carry risks and potential complications such as cataract formation, glaucoma, and inflammation. The current communication extensively reviews the available literature on vitreous tamponades. It details the composition and properties of various vitreous substitutes and tamponades available for the clinician, highlighting the techniques of usage, indications, and limitations.

Nanomedicine has the potential to increase the biostability of drugs to treat retinal diseases, improving their performance and decreasing the required number of intravitreal injections. However, accurate pharmacokinetic studies of these nanoparticle-drug conjugates, nanoparticle motion across the vitreous humour and interaction with the retinal cell layers still need to be investigated. Existing nanoparticle tracking techniques require fluorescent labels, which can impact cytotoxicity, nanoparticles\' motion, protein interactions, and cell internalization. In this study, a real-time label-free tracking technology, for single nanoparticles in an optical microscope based on the optical phenomena of caustics, was used to characterise the diffusion of nanoparticles in agar-hyaluronic acid hydrogels, previously validated as vitreous humour substitutes for in vitro models. The results demonstrated that the diffusion of nanoparticles through these hydrogels was heterogeneous, and that nanoparticle size had an important role in nanoparticle distribution across and within in vitro vitreous substitutes. These findings suggest that nanoparticle diameter is a critical parameter for designing novel therapeutics for retinal diseases. Moreover, nanoparticle charge did not affect nanoparticle diffusion or distribution in these synthetic hydrogels. The use of caustics in optical microscopy has been demonstrated to be a reproducible, inexpensive technique for screening novel therapeutics in eye in vitro models.

Previous studies reported the expression of toll-like receptors (TLRs), merely TLR2 and TLR4, and complement fragments (C3a, C5b9) in vitreoretinal disorders. Other than pathogens, TLRs can recognize endogenous products of tissue remodeling as damage-associated molecular pattern (DAMPs). The aim of this study was to confirm the expression of TLR2 and TLR4 in the fibrocellular membranes and vitreal fluids (soluble TLRs) of patients suffering of epiretinal membranes (ERMs) and assess their association with disease severity, complement fragments and inflammatory profiles. Twenty (n = 20) ERMs and twelve (n = 12) vitreous samples were collected at the time of the vitrectomy. Different severity-staged ERMs were processed for: immunolocalization (IF), transcriptomic (RT-PCR) and proteomics (ELISA, IP/WB, Protein Chip Array) analysis. The investigation of targets included TLR2, TLR4, C3a, C5b9, a few selected inflammatory biomarkers (Eotaxin-2, Rantes, Vascular Endothelial Growth Factor (VEGFA), Vascular Endothelial Growth Factor receptor (VEGFR2), Interferon-γ (IFNγ), Interleukin (IL1β, IL12p40/p70)) and a restricted panel of matrix enzymes (Matrix metalloproteinases (MMPs)/Tissue Inhibitor of Metallo-Proteinases (TIMPs)). A reduced cellularity was observed as function of ERM severity. TLR2, TLR4 and myD88 transcripts/proteins were detected in membranes and decreased upon disease severity. The levels of soluble TLR2 and TLR4, as well as C3a, C5b9, Eotaxin-2, Rantes, VEGFA, VEGFR2, IFNγ, IL1β, IL12p40/p70, MMP7 and TIMP2 levels were changed in vitreal samples. Significant correlations were observed between TLRs and complement fragments and between TLRs and some inflammatory mediators. Our findings pointed at TLR2 and TLR4 over-expression at early stages of ERM formation, suggesting the participation of the local immune response in the severity of disease. These activations at the early-stage of ERM formation suggest a potential persistence of innate immune response in the early phases of fibrocellular membrane formation.

OBJECTIVE: This study was designed to investigate retinal nerve fiber layer circumpapillary optical coherence tomography to determine posterior vitreous detachment (PVD) status and to develop a clinically relevant PVD grading scale based on retinal nerve fiber layer circumpapillary optical coherence tomography to determine the incidence of PVD by age and association with vitreomacular traction disorders.
METHODS: Ophthalmic images and medical records of patients with retinal diseases were retrospectively analyzed by three masked graders using retinal nerve fiber layer circumpapillary optical coherence tomography and macular optical coherence tomography. Based on PVD status, eyes were categorized into five newly defined PVD stages.
RESULTS: Among 2002 eyes, PVD stages were as follows: A) 25 (1.25%); B) 725 (36.21%); C-) 248 (12.39%); C+) 151 (7.54%); D) 851 (42.51%); X) 2 (0.1%). Posterior vitreous detachment was correlated with advanced age (P < 0.0001). Limited separation or partial separation between lamella within the posterior vitreous cortex (Stage B) was noted early (68% of eyes <18 years). Overall, 34% of eyes >70 years did not exhibit complete PVD. Of 75 eyes with tractional vitreoretinal disorders, 64 (85.3%) were Stage C-/C+, identifying Stage C as the high-risk \"complication\" stage.
CONCLUSIONS: Imaging analyses using retinal nerve fiber layer circumpapillary optical coherence tomography and macular optical coherence tomography scans in conjunction allow rapid assessment of the PVD stage. These techniques can assist clinicians and surgeons in counseling patients and planning surgical approaches. Observations confirmed the progression of PVD through predictable stages and the progression of PVD with age.

OBJECTIVE: Vitreous floaters, characterized by the perception of spots or shadows in the visual field, commonly result from posterior vitreous detachment and can cause chronic symptoms in affected patients. The diagnosis of posterior vitreous detachment is typically determined clinically and can sometimes be confirmed with optical coherence topography (OCT) [1 ▪▪ ] . The objective of this review is to review management options for symptomatic vitreous floaters.
RESULTS: Symptoms of vitreous floaters may be mild or may significantly affect patient quality of life. Observation is the most common management strategy. Procedural management options include pars plana vitrectomy (PPV) and neodymium-doped yttrium aluminium garnet (Nd:YAG) vitreolysis. PPV is considered the most definitive management option for vitreous floaters. PPV, however, carries inherent risks, notably infection, cataract formation, and retinal detachment [2] . Nd:YAG laser vitreolysis is a less invasive alternative with studies demonstrating varied success [1 ▪▪ ,3,4] .
CONCLUSIONS: This review provides insights into the current state of knowledge regarding the management of vitreous floaters and can guide clinical decision-making.

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Objective: This case report aimed to describe the unusual clinical presentation and histopathological features of post-injection endophthalmitis. Methods: A 56-year-old male phakic patient with diabetic retinopathy received an intravitreal injection (Bevacizumab as per the patient) for neovascular glaucoma elsewhere and presented to our center one day after the dose with hypopyon. The eye was relatively white without pain or lid oedema. The patient was treated as a case of post-injection endophthalmitis with two doses of intravitreal antibiotics 48 hours apart. During the follow-up, he developed a Covid infection. After one week, when the media cleared, white exudates were seen in the vitreous cavity with a relatively healthy retina. He was taken up for pars plana vitrectomy and vitreous biopsy for histopathological study. Results: The microscopic examination of vitreous aspirate revealed crystalline deposits without any microorganisms. Two control slides, one with a mixture of intravitreal antibiotics, which were previously injected, and the other with fresh Triamcinolone were also examined. Although the findings of the drug mixture did not match the vitreous aspirate, they matched with triamcinolone, which established it as a case of pseudo endophthalmitis due to triamcinolone injected elsewhere. Discussion: Initially, it seemed like a straightforward case of post-injection endophthalmitis, but a further examination of the vitreous aspirate showed that it was pseudoendophthalmitis due to an intravitreal triamcinolone injection. Despite the patient being phakic, neovascularization or elevated intraocular pressure may have led to the disruption of the blood-ocular barrier and the migration of Triamcinolone into the anterior chamber. Conclusion: The case\'s uniqueness lies in being the first reported case of pseudo endophthalmitis in a phakic patient with an intact lens iris diaphragm. The case also highlighted the judicious use of available resources and out-of-the-box thinking to reach a diagnosis that may not always be obvious. Abbreviations: TA = Triamcinolone acetonide, AC = Anterior chamber, IVB = Intravitreal Bevacizumab, PL = Perception of light.

OBJECTIVE: Evaluation of the effectiveness of pneumatic vitreolysis in disrupting vitreomacular traction in our own cohort of patients.
METHODS: Prospective follow-up of 21 eyes of 18 patients with focal VMT (adhesion width < 1500 µm) who underwent intravitreal injection of 0.3 ml of 100% perfluoropropane between January 2015 and December 2020. The patients were observed for 90 days.
RESULTS: Release of VMT was achieved on the 28th day of observation in 15 out of 21 eyes (71.4%), and by the 90th day in 19 out of 21 eyes (90.5%). The average width of adhesion in our patients was 382 µm (±212 µm). Average best corrected visual acuity in our cohort was initially 0.77 (±0.21), after 28 days 0.74 (±0.30), and after 3 months 0.82 (±0.21). At the end of the follow-up period, we did not observe a statistically significant improvement in vision. Macular holes developed in two eyes, but spontaneously closed within 1 month of observation, and no more complications were observed in the cohort.
CONCLUSIONS: Pneumatic vitreolysis by intravitreal injection of C3F8 gas is an effective and inexpensive option for the management of symptomatic vitreomacular traction. The incidence of serious adverse events in our follow-up was significantly lower than in recently published series. The method of management should be selected individually according to the parameters of adhesion, macular hole and associated ocular pathologies.

OBJECTIVE: To investigate whether the clinical characteristics, treatment and prognosis of endogenous infectious endophthalmitis (EIE) have changed over the past 5 years.
METHODS: Retrospectively analyze all articles about EIE published in the PubMed, Web of Science, and Embase databases from 2017 to 2021.
RESULTS: A total of 128 patients and 147 eyes (46 left and 60 right) were included in the study. The mean age at diagnosis was 51 ± 19 years. The most common risk factors were diabetes and intravenous drug use. From 2017 to 2021, Klebsiella was the most common pathogenic microorganism (22%), and vitreous culture had the highest positivity rate. The most common complaint was blurred vision. The mean visual acuity (logMAR) at onset was 2.84, and the clinical symptoms were vitreal inflammation and opacity (63%), ocular pain (37%), and conjunctival congestion (36%). The ocular inflammation could be reduced by intraocular antibiotics or vitrectomy. However, the visual prognosis, with a mean logMAR of 2.73; only 50% of the eyes reached a visual acuity level of finger count and above. Changes in diagnostics over the past 5 years have mainly manifested as more diverse microorganism culture methods. In addition to conventional culture methods, PCR, sputum culture and aqueous humour culture are also commonly used for the diagnosis of pathogenic bacteria, improving the positive culture rate and visual prognosis.
CONCLUSIONS: The prognosis of EIE is poor. It is recommended to pay attention to the pathogenic bacteria culture results and accompanying systemic diseases and to diagnose and treat patients as soon as possible.

UNASSIGNED: First- (monomers), second- (pre-gelated), and third- (in situ gelating after injection) generation hydrogels were previously introduced to replace the vitreous body after vitrectomy surgery. In this study, we evaluated the surgical, optical, and viscoelastic properties of vitreous body replacement hydrogels before and after an accelerated aging protocol previously applied to intraocular implants.
UNASSIGNED: Measurements of injection force, removal speed using a clinically established vitrectomy setup, as well as evaluation of forward light scattering and viscoelastic properties before and after an accelerated aging protocol were conducted. Results were compared to porcine and human vitreous bodies, as well as currently clinically applied lighter- and heavier-than-water silicone oils.
UNASSIGNED: Removal speed of all tested hydrogels is substantially lower than the removal speed of porcine vitreous body (0.2 g/min vs. 2.7 g/min for the best performing hydrogel and porcine vitreous body, respectively). Forward light scattering in second-generation vitreous body replacement hydrogels was higher after the aging process than the straylight of the average 70-year-old vitreous body (9.4 vs. 5.5 deg2/sr, respectively). The viscoelastic properties of all hydrogels did not change in a clinically meaningful manner; however, trends toward greater stiffness and greater elasticity after aging were apparent.
UNASSIGNED: This study demonstrates surgical weaknesses of the hydrogels that need to be addressed before clinical use, especially low removal speed. Pre-linked hydrogels (second-generation) showed inferior performance regarding surgical properties compared to in situ gelating hydrogels (third-generation).
UNASSIGNED: This study highlights possible pitfalls regarding surgical and optical properties when applying vitreous replacement hydrogels clinically.