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Investigative Ophthalmology & Visual... Sep 2023Water inflow into the vitreous body regulated by retinal aquaporin-4 distributed within Müller cells has been observed in mice; however, the changes in this phenomenon...
PURPOSE
Water inflow into the vitreous body regulated by retinal aquaporin-4 distributed within Müller cells has been observed in mice; however, the changes in this phenomenon with age remain unknown. This study aimed to evaluate whether intravenously injected H2O also flows into the vitreous body of human subjects and to investigate whether water dynamics in the human posterior eye change with age using [15O]H2O positron emission tomography (PET).
METHODS
Forty-six normal adult volunteers underwent [15O]H2O PET, and the standard uptake value (SUV) in the center of the vitreous body after 1000-MBq [15O]H2O administration was assessed. The SUV was fitted to an exponential curve, and y0, the steady state of the SUV, and b, the speed of increase in the SUV, were calculated. The results for patients ranging from in age from 20 to 39, 40 to 59, and 60 to 79 years were compared using analyses of variance followed by Games to Howell tests.
RESULTS
For the parameter y0, statistical analysis revealed no statistically significant differences among the three groups. For parameter b, statistical analysis revealed statistically significant differences between the 20 to 39 and 60 to 79 age groups (P = 0.000), the 40 to 59 and 60 to 79 age groups (P = 0.025), and the 20 to 39 and 40 to 59 age groups (P = 0.037).
CONCLUSIONS
The present study revealed that H2O injected into the vein flows into the human vitreous body and that the speed of increase in water flow into the vitreous body decreases with aging. This study suggests that water dynamics in the posterior eye, or the retinal glymphatic pathway, change significantly with aging.
Topics: Adult; Humans; Animals; Mice; Young Adult; Vitreous Body; Aging; Aquaporin 4; Biological Transport
PubMed: 37698528
DOI: 10.1167/iovs.64.12.22 -
Seminars in Ophthalmology 2017Vitreomacular adhesion (VMA) describes the adhesion of the posterior hyaloid face to the inner retina in any part of the macula. This can arise after incomplete... (Review)
Review
Vitreomacular adhesion (VMA) describes the adhesion of the posterior hyaloid face to the inner retina in any part of the macula. This can arise after incomplete separation of the posterior vitreous cortex from the macula during vitreous liquefaction. While the VMA may resolve spontaneously, a strong and persistent adhesion can lead to a variety of anatomical changes, including vitreomacular traction (VMT) and macular hole (MH). Both conditions can present with metamorphopsia and decreased vision. In cases of symptomatic VMT and full-thickness macular hole, pars plana vitrectomy has long been the standard of care. However, due to the possible surgical complications and need for postoperative care, many have searched for non-surgical options via pharmacologic vitreolysis. Ocriplasmin (Jetrea, Thrombogenics USA, Alcon/Novartis EU) is a recombinant protease approved in October 2012 for the treatment of symptomatic vitreomacular adhesion (VMA). There have been conflicting views on the safety of Ocriplasmin with changes in the ellipsoid zone seen on OCT and changes seen on ERG indicating photoreceptor damage. This publication reviews the efficacy and safety of ocriplasmin injection for VMA based on previously published data.
Topics: Fibrinolysin; Fibrinolytic Agents; Humans; Peptide Fragments; Retinal Diseases; Tissue Adhesions; Treatment Outcome; Vitreous Body; Vitreous Detachment
PubMed: 27786583
DOI: 10.1080/08820538.2016.1228416 -
International Ophthalmology Clinics 2020
Review
Topics: Equipment Design; Humans; Imaging, Three-Dimensional; Ophthalmologic Surgical Procedures; Vitrectomy; Vitreoretinal Surgery; Vitreous Body
PubMed: 31855892
DOI: 10.1097/IIO.0000000000000291 -
Ophthalmology Nov 2019Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser treatment is performed on vitreous floaters, but studies of structural and functional effects with objective outcome... (Comparative Study)
Comparative Study
PURPOSE
Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser treatment is performed on vitreous floaters, but studies of structural and functional effects with objective outcome measures are lacking. This study evaluated Nd:YAG laser effects by comparing participants with vitreous floaters who previously underwent laser treatment with untreated control participants and healthy persons without vitreous floaters using quantitative ultrasonography to evaluate vitreous structure and by measuring visual acuity and contrast sensitivity function to assess vision.
DESIGN
Retrospective, comparative study.
PARTICIPANTS
One eye was enrolled for each of 132 participants: 35 control participants without vitreous floaters, 59 participants with untreated vitreous floaters, and 38 participants with vitreous floaters previously Nd:YAG-treated. Of these, 25 were dissatisfied and sought vitrectomy; 13 were satisfied with observation.
METHODS
The 39-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-39) to assess participant visual well-being, quantitative ultrasonography (QUS) to measure vitreous echodensity, and best-corrected visual acuity (BCVA) and contrast sensitivity function (CSF) to evaluate vision.
MAIN OUTCOME MEASURES
Results of NEI-VFQ-39, QUS, BCVA, and CSF.
RESULTS
Compared with control participants without vitreous floaters, participants with untreated vitreous floaters showed worse NEI-VFQ-39 results, 57% greater vitreous echodensity, and significant (130%) CSF degradation (P < 0.001 for each). Compared with untreated eyes with vitreous floaters, Nd:YAG-treated eyes had 23% less vitreous echodensity (P < 0.001), but no differences in NEI-VFQ-39 (P = 0.51), BCVA (P = 0.42), and CSF (P = 0.17) results. Of 38 participants with vitreous floaters who previously were treated with Nd:YAG, 25 were dissatisfied and seeking vitrectomy, whereas 13 were satisfied with observation. Participants seeking vitrectomy showed 24% greater vitreous echodensity (P = 0.018) and 52% worse CSF (P = 0.006). Multivariate linear regression models confirmed these findings.
CONCLUSIONS
As a group, participants previously treated with Nd:YAG laser for bothersome vitreous floaters showed less dense vitreous, but similar visual function as untreated control participants with vitreous floaters. Because some treated eyes showed less dense vitreous and better visual function than those of untreated control participants, a prospective randomized study of Nd:YAG laser treatment of vitreous is warranted, using uniform laser treatment parameters and objective quantitative outcome measures.
Topics: Adult; Aged; Contrast Sensitivity; Eye Diseases; Female; Humans; Lasers, Solid-State; Male; Middle Aged; Ophthalmoscopy; Patient Satisfaction; Retrospective Studies; Sickness Impact Profile; Surveys and Questionnaires; Ultrasonography; Visual Acuity; Vitrectomy; Vitreous Body
PubMed: 31471088
DOI: 10.1016/j.ophtha.2019.06.021 -
Experimental Eye Research May 2020Vitreous liquefactive processes play an integral role in ocular health. Knowledge of the degree of liquefaction would allow better monitoring of ocular disease...
Vitreous liquefactive processes play an integral role in ocular health. Knowledge of the degree of liquefaction would allow better monitoring of ocular disease progression and enable more informed therapeutic dosing for an individual patient. Presently this process cannot be monitored in a non-invasive manner. Here, we evaluated whether magnetic resonance imaging (MRI) could predict the viscoelasticity and in turn liquefactive state of artificial and biological vitreous humour. Gels comprising identical concentrations of hyaluronic acid and agar ranging from 0.125 to 2.25 mg/ml of each polymer were prepared and their T2 was measured using a turbo-spin echo sequence via 3T clinical MRI. The gels were subsequently subjected to rheological frequency and flow sweeps and trends between T2 and rheological parameters were assessed. The relationship between T2 and vitreous humour rheology was further assessed using ex vivo porcine eyes. An optimised imaging technique improved homogeneity of obtained artificial vitreous humour T2 maps. Strong correlations were observed between T2 and various rheological parameters of the gels. Translation to porcine vitreous humour demonstrated that the T2 of biological tissue was related to its viscoelastic properties. This study shows that T2 can be correlated with various rheological parameters within gels. Future investigations will assess the translatability of these findings to live models.
Topics: Animals; Magnetic Resonance Imaging; Models, Animal; Swine; Viscosity; Vitreous Body
PubMed: 32194065
DOI: 10.1016/j.exer.2020.108006 -
Ophthalmic Surgery, Lasers & Imaging... May 2023To introduce VFO and SK VFO Test: new, more representative terminology for symptoms of vitreous floaters/opacities (VFO) and new standardized kinetic (SK)...
New Terminology and Methodology for the Assessment of the Vitreous, Its Floaters and Opacities, and Their Effect on Vision: Standardized and Kinetic Anatomical and Functional Testing of Vitreous Floaters and Opacities (SK VFO Test).
OBJECTIVE
To introduce VFO and SK VFO Test: new, more representative terminology for symptoms of vitreous floaters/opacities (VFO) and new standardized kinetic (SK) anatomical-functional assessment.
MATERIALS AND METHODS
Eight eyes underwent before-after limited vitrectomy (LV): best-corrected visual acuity, low-luminance visual acuity, Minnesota Low Vision Reading Chart near visual acuity in logMAR, contrast sensitivity function (CV1000E), and straylight measurements (SM) (HDA/LDA/C-Quant). SK infrared confocal scanning laser ophthalmoscopy (SK IRcSLO) and swept-source widefield optical coherence tomography (SS-WF-OCT) identified VFO and posterior vitreous detachment (PVD). SK IRcSLO was performed with gaze directed towards the extreme superior, inferior, and lateral directions.
RESULTS
Anatomical-functional results after LV improved in 7 eyes (87.5%): objective scatter index (27.34%), disturbance index (47.97%) and C-Quant Log units (2.26%). Pre-LV SK IRcSLO and SS-WFOCT imaging identified dynamic well-defined VFO and PVD status (100%). A residual asymptomatic anterior cortical vitreous-induced shadowing ripple effect was detected post-LV.
CONCLUSIONS
This is the first objective-standardized test accounting for VFO kinesis and intermittent effect. There is potential for personalizing treatment and establishing best candidates for laser or surgery. .
Topics: Humans; Vitreous Body; Vision Disorders; Vitreous Detachment; Vitrectomy
PubMed: 37184989
DOI: 10.3928/23258160-20230412-02 -
Ophthalmic Research 2022The aim of this study was to compare the flow dynamics of the dual-blade to the single-blade beveled-tip vitreous cutters.
INTRODUCTION
The aim of this study was to compare the flow dynamics of the dual-blade to the single-blade beveled-tip vitreous cutters.
METHODS
The aspiration rates of balanced salt solution (BSS) and swine vitreous were measured for the 25-gauge and 27-gauge dual- and single-blade beveled-tip vitreous cutters. The flow dynamics of BSS and diluted vitreous mixed with fluorescent polymer at the maximal cutting rates and the reflux of BSS were measured in images obtained by a high-speed camera. The distal end of the cutter was defined as the head end.
RESULTS
The aspiration rates of BSS and vitreous by the 25- and 27-gauge dual-blade cutters were significantly higher than those of both single-blade cutters at the maximal cutting rate (all p ≤ 0.01). The mean aspiration flow of BSS in front of the port from a lateral view was significantly faster for both dual-blade cutters than for both single-blade cutters (p = 0.003, p = 0.019). The angle of the mean flow of BSS of both dual-blade cutters was from the distal end (p < 0.001, p < 0.001) but that of the single-blade cutters was from the proximal end. The velocity and angle of the mean reflux flow of both types of cutters were not significantly different. The mean aspiration flow of diluted vitreous was significantly faster for 25-gauge dual-blade cutters with the angle more from the proximal end and 27-gauge dual-blade cutters more from the distal end than both single-blade cutters (p = 0.018, p = 0.048).
CONCLUSION
The dual-blade beveled-tip vitreous cutters improve the efficiency of the vitrectomy procedures and maintain the distal aspirating flow by the beveled tip.
Topics: Animals; Microsurgery; Swine; Vitrectomy; Vitreous Body
PubMed: 34942621
DOI: 10.1159/000521468 -
Scientific Reports Aug 2022The structure of the human vitreous varies considerably because of age-related liquefactions of the vitreous gel. These changes are poorly studied in vivo mainly because...
The structure of the human vitreous varies considerably because of age-related liquefactions of the vitreous gel. These changes are poorly studied in vivo mainly because their high transparency and mobility make it difficult to obtain reliable and repeatable images of the vitreous. Optical coherence tomography can detect the boundaries between the vitreous gel and vitreous fluid, but it is difficult to obtain high resolution images that can be used to convert the images to three-dimensional (3D) images. Thus, the purpose of this study was to determine the shape and characteristics of the vitreous fluid using machine learning-based 3D modeling in which manually labelled fluid areas were used to train deep convolutional neural network (DCNN). The trained DCNN labelled vitreous fluid automatically and allowed us to obtain 3D vitreous model and to quantify the vitreous fluidic cavities. The mean volume and surface area of posterior vitreous fluidic cavities are 19.6 ± 7.8 mm and 104.0 ± 18.9 mm in eyes of 17 school children. The results suggested that vitreous fluidic cavities expanded as the cavities connects with each other, and this modeling system provided novel imaging markers for aging and eye diseases.
Topics: Child; Humans; Machine Learning; Neural Networks, Computer; Tomography, Optical Coherence; Vision Disorders; Vitreous Body
PubMed: 35974072
DOI: 10.1038/s41598-022-17615-z -
Fa Yi Xue Za Zhi Apr 2018Postmortem interval (PMI) estimation is one of the most challenging problems in the field of forensic science. Vitreous humor is a hotspot which has been used for... (Review)
Review
Postmortem interval (PMI) estimation is one of the most challenging problems in the field of forensic science. Vitreous humor is a hotspot which has been used for PMI estimation and postmortem chemical analysis in forensic pathology. In order to provide novel perspectives for the future research of PMI estimation using vitreous humor, the comparison between vitreous humor with other common body fluids, the effect of temperature on vitreous humor, vitreous humor detection method and data fitting method have been reviewed in this paper.
Topics: Autopsy; Body Fluids; Forensic Pathology; Forensic Sciences; Humans; Postmortem Changes; Potassium; Temperature; Time Factors; Vitreous Body
PubMed: 29923384
DOI: 10.3969/j.issn.1004-5619.2018.02.013 -
International Ophthalmology Oct 2023To demonstrate the methodology and efficacy of using scanning laser ophthalmoscopy (SLO) and dynamic optical coherence tomography (OCT) to identify and treat symptomatic...
PURPOSE
To demonstrate the methodology and efficacy of using scanning laser ophthalmoscopy (SLO) and dynamic optical coherence tomography (OCT) to identify and treat symptomatic vitreous floaters using yttrium-aluminum garnet laser vitreolysis (YLV).
METHODS
This is a case series highlighted from a cross sectional retrospective study conducted at the Vitreous Retina Macula Specialists of Toronto. Forty eyes from thirty-five patients were treated with YLV between November 2018 and December 2020 for symptomatic floaters and imaged with SLO and dynamic OCT. Patients were re-treated with YLV if they reported ongoing significant vision symptoms during follow-up which correlated to visible opacities on exam and or imaging. Three cases will be highlighted to present the practical applications of SLO and dynamic OCT imaging for YLV treatment.
RESULTS
Forty treated eyes were enrolled in this study, with twenty-six eyes (65%) requiring at least one repeat YLV treatment following the first treatment due to ongoing symptomatic floaters. Following the first YLV, there was a significant improvement in overall mean best corrected visual acuity compared to before treatment (0.11 ± 0.20 LogMAR units vs. 0.14 ± 0.20 LogMAR units, p = 0.02 (paired t test)). Case 1 demonstrates a dense, solitary vitreous opacity that has been localized with dynamic OCT imaging to track its movements and retinal shadowing with the patient's eye movements. Case 2 shows the utility of adjusting the fixation target to monitor the movement of vitreous opacities in real-time. Case 3 exhibits an association between decreased symptom burden and vitreous opacity density after YLV.
CONCLUSION
Image-guided YLV facilitates the localization and confirmation of vitreous opacities. SLO and dynamic OCT of the vitreous can provide a real-time evaluation of floater size, movement, and morphology, to help clinicians target treatment and monitoring of symptomatic floaters.
Topics: Humans; Retrospective Studies; Cross-Sectional Studies; Vitrectomy; Eye Diseases; Vitreous Body; Vision Disorders; Tomography, Optical Coherence
PubMed: 37402010
DOI: 10.1007/s10792-023-02765-4