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Retina (Philadelphia, Pa.) Feb 2021To compare the flow dynamics of beveled-tip to that of flat-tip vitreous cutters.
PURPOSE
To compare the flow dynamics of beveled-tip to that of flat-tip vitreous cutters.
METHOD
The aspiration rates of balanced salt solution and swine vitreous were measured for 25-gauge and 27-gauge beveled-tip and flat-tip vitreous cutters. Fluorescent polymer microspheres were mixed with balanced salt solution to make the flow visible. The flow dynamics at maximal cutting rates and reflux of balanced salt solution were measured with video images of a high-speed camera.
RESULTS
The aspiration rates of balanced salt solution of the 25-gauge and 27-gauge beveled-tip cutters were significantly higher than that of the flat-tip cutters at 7,500 cut/min (P = 0.0001, P = 0.038, respectively). The aspiration rate of swine vitreous by the 25-gauge beveled-tip cutter was significantly higher than that of the flat-tip cutters (P = 0.006). The mean aspiration flow in front of the cutter was significantly faster for both beveled-tip than flat-tip cutters (P = 0.003, P = 0.023). The angle of the mean aspiration flow of both beveled-tip cutters was turned to the proximal side (P = 0.004, P = 0.003). The mean reflux flow of both beveled-tip cutters was significantly faster than that of the flat-tip cutters (P = 0.006, P = 0.006).
CONCLUSION
The beveled-tip cutters have a greater velocity of aspirating frontal and proximal flow resulting in higher aspiration rates and greater reflux flow velocity.
Topics: Animals; Disease Models, Animal; Microsurgery; Saline Solution; Swine; Video Recording; Vitrectomy; Vitreous Body
PubMed: 32271276
DOI: 10.1097/IAE.0000000000002811 -
Translational Vision Science &... Feb 2023The purpose of this study was to assess the performance of ultrasonic (US) vitrectomy devices by quantifying and comparing its impact on extracted vitreous properties to...
PURPOSE
The purpose of this study was to assess the performance of ultrasonic (US) vitrectomy devices by quantifying and comparing its impact on extracted vitreous properties to conventional pneumatic blade (PB) cutters using micro-extensional rheology. US vitrectomy is a new technology that offers an alternative to PB cutters used in vitreo-retinal surgeries.
METHODS
Thirty-six porcine vitreous samples were extracted using US and PB cutters. Each sample was kept at 4°C and tested within 24 hours postmortem and 4 hours post-vitrectomy. A recently developed micro-extensional rheology technique is used to infer the relative protein fragment size of extracted vitreous by quantifying the extensional relaxation time.
RESULTS
US-extracted vitreous exhibited extensional relaxation times orders of magnitude lower than PB-extracted vitreous (0.37 ms and 27.25 ms, respectively). Relaxation time is directly correlated to the fragment size of the collagen fibers in the vitreous. The formation of beads-on-a-string droplets within the PB samples indicates the presence of larger collagen fragments. These droplets were not seen on US samples.
CONCLUSIONS
This new micro-extensional rheology technique can identify significant differences in physical properties of extracted vitreous. Long relaxation times and beads-on-a-string droplets within the PB vitreous samples indicate larger protein fragments compared to the US samples.
TRANSLATIONAL RELEVANCE
Higher fragmentation of vitreous and lower extensional relaxation times may improve retina safety due to a reduction in vitreo-retinal traction resulting from the continuous shear action and aspiration applied by ultrasonic vitrectomy technology.
Topics: Swine; Animals; Vitrectomy; Vitreous Body; Ultrasonics; Collagen; Rheology
PubMed: 36790819
DOI: 10.1167/tvst.12.2.24 -
American Journal of Ophthalmology Sep 1958
Topics: Humans; Ultrasonics; Vitreous Body
PubMed: 13571346
DOI: 10.1016/0002-9394(58)90264-2 -
Albrecht Von Graefes Archiv Fur... 1980The formation of vitreous membranes after intravitreal haemorrhage was studied in rabbit eyes. Early detachment of the posterior vitreous was followed by the formation...
The formation of vitreous membranes after intravitreal haemorrhage was studied in rabbit eyes. Early detachment of the posterior vitreous was followed by the formation of large cellular membranes, composed of aggregated giant macrophages within fine collagen sheets. Progressive reabsorption of the cellular material resulted in acellular membranes composed of endogenous vitreous collagen. Fibroblastic activity was not observed, and it was considered that the vitreous body, particularly its hyaluronic acid component, may present a barrier to the invasion of fibroblasts and other cells during the resolution of vitreous clots.
Topics: Animals; Eye Diseases; Hemorrhage; Membranes; Rabbits; Time Factors; Vitreous Body
PubMed: 6906136
DOI: 10.1007/BF00410518 -
Journal Francais D'ophtalmologie Jun 2007The persistence of the fetal vascular system is a rare ocular malformation whose origin remains unknown. It comprises a group of complex ocular malformations from which... (Review)
Review
The persistence of the fetal vascular system is a rare ocular malformation whose origin remains unknown. It comprises a group of complex ocular malformations from which the various clinical forms have a heterogeneous functional prognosis. The diagnosis depends on a precise and complete examination of the child's eye, often under general anesthesia. Various clinical forms can be found together, ranging from the tiny form with no visual repercussion or ocular or systemic anomaly associated with the major forms involving the totality of the ocular structures and systemic syndromes. A systematic general pediatric examination is therefore recommended. The treatment is adapted individually for early and specific surgical and medical treatment. In the event of intervention, the induced aphakia will be corrected in one procedure with an implantation, generally sutured with the sclera, or at the time of a second intervention after the wearing of glasses or a contact lens. However, the complications can sometimes lead to rapid phthisis bulbi. Whatever solution is chosen, the final functional result has progressed thanks to early diagnosis, the surgical techniques suggested, even if implantation continues to be debated. Amblyopia must be treated for the entire sensitive period. However, despite good rehabilitation, the average functional prognosis remains disappointing, probably because of the overall ocular malformation.
Topics: Abnormalities, Multiple; Amblyopia; Aphakia; Child, Preschool; Diagnostic Techniques, Ophthalmological; Eye Abnormalities; Female; Humans; Hyperplasia; Infant; Infant, Newborn; Lens Implantation, Intraocular; Lens, Crystalline; Male; Postoperative Complications; Ultrasonography; Vitrectomy; Vitreous Body
PubMed: 17646755
DOI: 10.1016/s0181-5512(07)89674-4 -
Inflammation & Allergy Drug Targets Aug 2011The immune system protects organisms against environmental and endogenous pathogens. By complex mechanisms, it regulates the homeostasis of inflammatory processes and... (Review)
Review
The immune system protects organisms against environmental and endogenous pathogens. By complex mechanisms, it regulates the homeostasis of inflammatory processes and tissue repair mechanisms. In the retina, these pathways can result in an irreversible tissue scar, which is related to malfunction and loss of function. In the aging retina, inflammation plays a major role and causes adverse effects. Several ophthalmological diseases contain aspects of maladjusted inflammatory processes. This review summarizes the general function of the immune system and its regulatory mechanisms in the vitreoretinal compartment. Next to non-pathological inflammatory processes, the review presents aspects of inflammation in the aging retina, AMD, glaucoma, uveitis and diabetic retinopathy. A better understanding of the complex immunology of the eye and inflammation of the vitreoretinal compartment may guide us towards more effective therapies for these very prevalent eye conditions.
Topics: Humans; Immune System; Immunity, Innate; Inflammation; Retina; Vitreous Body
PubMed: 21539511
DOI: 10.2174/187152811796117717 -
The British Journal of Ophthalmology Jun 1953
Topics: Microscopy; Vitreous Body
PubMed: 13059269
DOI: 10.1136/bjo.37.6.343 -
International Ophthalmology Clinics 1973
Review
Topics: Adult; Age Factors; Animals; Basement Membrane; Cattle; Cell Membrane; Collagen; Eye Diseases; Haplorhini; Humans; Hyaluronic Acid; Macrophages; Microscopy, Electron; Middle Aged; Models, Biological; Retinal Degeneration; Retinal Detachment; Species Specificity; Viscosity; Vitreous Body
PubMed: 4204768
DOI: No ID Found -
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 -
Bulletin de La Societe Belge... 1987