1
|
Wilson DI, Te Water Naude AD, Snead MP. Refinements in the use of silicone oil as an intraocular tamponade. Eye (Lond) 2024; 38:1810-1815. [PMID: 38548945 PMCID: PMC11226643 DOI: 10.1038/s41433-024-03027-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/15/2024] [Accepted: 03/08/2024] [Indexed: 07/07/2024] Open
Abstract
It is over 60 years since Paul Cibis et al. reported the experimental use of liquid silicone in the surgical management of retinal detachment. Initial experiences were complicated by significant side-effects associated with the impurities in the non-medical grade commercial silicone oils deployed at the time. These were substantially reduced (but not eliminated) by the adoption of refined high-viscosity medical grade silicone oils. Two of the major complications associated with silicone tamponade are (i) the variability of focus due to its movement and higher refractive index, and (ii) progressive emulsification, particularly with low viscosity oils. This article reviews recent and ongoing research on the causes of emulsification of intra-ocular silicone oil to understand the causes better and thereby reduce this risk, especially for those eyes where permanent tamponade is the only current option for retaining vision.
Collapse
Affiliation(s)
- D Ian Wilson
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK.
| | - Andrew D Te Water Naude
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Martin P Snead
- Vitreoretinal Service, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge, CB2 2QQ, UK
| |
Collapse
|
2
|
Januschowski K, Rickmann A, Smith J, Pastor-Idoate S, Pastor JC. Vision loss associated with silicone oil endotamponade in vitreoretinal surgery - a review. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06520-y. [PMID: 38888804 DOI: 10.1007/s00417-024-06520-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/25/2024] [Accepted: 05/08/2024] [Indexed: 06/20/2024] Open
Abstract
PURPOSE To clarify the definition, prevalence and classification of different types of unexplained vision loss associated with silicone oil (SO) endotamponades (SO in situ (SOIS) or after removal of SO (ROSO)) in vitreoretinal surgery and identifying the most specific clinical findings and suggesting possible causes. METHODS Review of the literature regarding randomized clinical trials (RCTs), retrospective case-control, cohort studies and case series evaluating the risk of using SO, published in English between 1994 and 2023, conducting a computer-based search of the following databases: PubMed, Web of Science, Scopus and Embase. The search was supplemented using the Medline option 'Related Articles' and consulting review articles on the topic. RESULTS Findings from reported clinical examinations in SOIS and ROSO are analyzed and finally different theories regarding the underlying pathophysiology are described. From the clinical point of view, findings have been found in OCT, OCTA, microperimetry and electrophysiological studies. Other clearly identifiable causes of vision loss related to the use of SO are listed and commented as differential diagnosis. Finally, the different physiopathological theories of the two types of causes of unexplained vision have been analyzed. CONCLUSION Unexpected vision loss under or after SO tamponade (SOIS and ROSO) is a significant concern which is probably underestimated because it is not a clearly defined and known entity. The most frequently described changes were in the ganglion cell complex but this unexpected vision loss remains a serious and unexplained concern for vitreoretinal surgeons and should be identified by clinicians, addressed by manufacturers and reported to Health Authorities as a serious incident according to the new regulation.
Collapse
Affiliation(s)
- Kai Januschowski
- Mount St. Peter Eye Clinic, Max-Planck-Str. 14-16, 54296, Trier, Germany
- Medical Department, University of Tuebingen, Tuebingen, Germany
| | - Annekatrin Rickmann
- Medical Department, University of Tuebingen, Tuebingen, Germany.
- Ophthalmology Department, Knappschaft Hospital Sulzbach, Sulzbach/Saar, Germany.
| | - Jonathan Smith
- Sunderland Eye Infirmary, Queen Alexandra Road, Sunderland, SR2 9HP, UK
| | - Salvador Pastor-Idoate
- Institute of Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain
- Ophthalmology Department, Hospital Clinico Universitario, Valladolid, Spain
| | - Jose Carlos Pastor
- Institute of Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain
| |
Collapse
|
3
|
Ledda PG, Rossi T, Badas MG, Querzoli G. Can wall shear-stress topology predict proliferative vitreoretinopathy localization following pars plana vitrectomy? J Biomech 2024; 162:111914. [PMID: 38157782 DOI: 10.1016/j.jbiomech.2023.111914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
We numerically study the fluid dynamics of oil tamponade in models of vitrectomized eyes prompted by a subset of daily activities corresponding to movements on the horizontal plane with the patient in a standing position. Bulk flow features are related to near-wall flow topology and transport at the retinal surface through a wall shear-stress-based analysis. Proliferative VitreoRetinopathy (PVR) is the leading cause of retinal re-detachment occurring in about 20% of all cases due to the accumulation of inflammatory cells in discrete retinal regions. Signalling soluble mediators stimulate inflammatory cells' chemotaxis and studying their distribution across the retinal surface may acquire clinical relevance. In all the investigated cases, persistent and elongated regions along the retina, potentially prone to accumulate chemo-attractants and cells are observed. Gradients of soluble inflammation mediators present in the aqueous are known responsible for the so-called epithelial-mesenchymal transition that initiates PVR and favours recurrent retinal detachment prompting the proliferation of inflammatory cells with collagen matrix deposition and its contraction. The surgical apposition of encircling scleral buckling elements, known for over a century to influence PVR formation and localization, modifies the attracting regions, possibly causing an accumulation of molecules and cells along approximately vertical lines that follow the rising menisci due to the cerclage indentation. The resulting spatial pattern is compatible with clinical observations. This study may open toward rational analyses of near-wall transport to predict PVR pathogenesis by relating biochemical accumulation in certain areas of the retina to clinical conditions.
Collapse
Affiliation(s)
- P G Ledda
- DICAAR, Università degli Studi di Cagliari, Cagliari, Italy
| | - T Rossi
- IRCCS Fondazione G.B. Bietti ONLUS, Rome, Italy
| | - M G Badas
- DICAAR, Università degli Studi di Cagliari, Cagliari, Italy
| | - G Querzoli
- DICAAR, Università degli Studi di Cagliari, Cagliari, Italy.
| |
Collapse
|
4
|
Rossi T, Badas MG, Angius F, Querzoli G. DO DAILY ACTIVITIES AFFECT GAS TAMPONADE‒RETINA CONTACT AFTER PARS PLANA VITRECTOMY?: A Computational Fluid Dynamics Study. Retina 2023; 43:955-963. [PMID: 36800522 PMCID: PMC10187623 DOI: 10.1097/iae.0000000000003750] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
PURPOSE To calculate the retinal surface alternatively in contact with gas and aqueous because of fluid sloshing during daily activities such as ocular saccade, turning the head, standing up, and being a passenger of a braking car. METHODS Fluid dynamics of aqueous and gas tamponade was reproduced using computational methods using the OpenFOAM open-source library. The double-fluid dynamics was simulated by the volume of fluid method and setting the contact angle at the aqueous-gas-retina interface. RESULTS Sloshing increased the retinal surface in contact with aqueous by 13% to 16% regardless of fill rate and standing up determined the largest area of wet retina, followed by car braking, head rotation, and ocular saccade ( P < 0.001). All activities except the ocular saccade determined a significant increase in the surface of retina in contact with the aqueous ( P < 0.005). Car braking induced the highest shear stress (6.06 Pa); standing up determined the highest specific impulse and saccade the lowest. CONCLUSION Daily activities instantaneously reduce the amount of retina consistently in contact with gas tamponade and increase shear stress giving aqueous a potential access to the subretinal space regardless of patients' compliance.
Collapse
Affiliation(s)
- Tommaso Rossi
- IRCCS Fondazione G.B. Bietti ONLUS, Roma, Italy; and
| | | | | | | |
Collapse
|
5
|
Johnston A, Callanan A. Recent Methods for Modifying Mechanical Properties of Tissue-Engineered Scaffolds for Clinical Applications. Biomimetics (Basel) 2023; 8:biomimetics8020205. [PMID: 37218791 DOI: 10.3390/biomimetics8020205] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/03/2023] [Accepted: 05/12/2023] [Indexed: 05/24/2023] Open
Abstract
The limited regenerative capacity of the human body, in conjunction with a shortage of healthy autologous tissue, has created an urgent need for alternative grafting materials. A potential solution is a tissue-engineered graft, a construct which supports and integrates with host tissue. One of the key challenges in fabricating a tissue-engineered graft is achieving mechanical compatibility with the graft site; a disparity in these properties can shape the behaviour of the surrounding native tissue, contributing to the likelihood of graft failure. The purpose of this review is to examine the means by which researchers have altered the mechanical properties of tissue-engineered constructs via hybrid material usage, multi-layer scaffold designs, and surface modifications. A subset of these studies which has investigated the function of their constructs in vivo is also presented, followed by an examination of various tissue-engineered designs which have been clinically translated.
Collapse
Affiliation(s)
- Andrew Johnston
- Institute for Bioengineering, School of Engineering, University of Edinburgh, Edinburgh EH9 3DW, UK
| | - Anthony Callanan
- Institute for Bioengineering, School of Engineering, University of Edinburgh, Edinburgh EH9 3DW, UK
| |
Collapse
|
6
|
Optimization of patient positioning for improved healing after corneal transplantation. J Biomech 2023; 150:111510. [PMID: 36863199 DOI: 10.1016/j.jbiomech.2023.111510] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 02/26/2023]
Abstract
Corneal transplantation is the only solution which avoids loss of vision, when endothelial cells are dramatically lost. The surgery involves injecting gas into the anterior chamber of the eye, to create a bubble that pushes onto the donor cornea (graft), achieving sutureless adherence to the host cornea. During the postoperative period, patient positioning affects the bubble. To improve healing, we study the shape of the gas-bubble interface throughout the postoperative period, by numerically solving the equations of fluid motion. Patient-specific anterior chambers (ACs) of variable anterior chamber depths (ACD) are considered, for either phakic (with natural lens) and pseudophakic (with artificial lens) eyes. For each AC, gas-graft coverage is computed for different gas fill and patient positioning. The results show that the influence of positioning is negligible, regardless of gas filling, as long as the ACD is small. However, when the ACD value increases, patient positioning becomes important, especially for pseudophakic ACs. The difference between best and worst patient positioning over time, for each AC, is negligible for small ACD but significant for larger ACD, especially for pseudophakic eyes, where guidelines for optimal positioning become essential. Finally, mapping of the bubble position highlights the importance of patient positioning for an even gas-graft coverage.
Collapse
|
7
|
Rossi T, Querzoli G, Badas MG, Angius F, Ripandelli G. Silicone Oil Tamponade-Retina Contact in Highly Myopic Eyes With and Without Encircling Bands: A Computational Fluid Dynamics Study. Transl Vis Sci Technol 2022; 11:1. [PMID: 35648638 PMCID: PMC9172018 DOI: 10.1167/tvst.11.6.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose To investigate the behavior of silicone oil (SiO) at a steady equilibrium and during saccades in pseudophakic highly myopic eyes with posterior staphyloma with and without an encircling band and compare it to behavior in emmetropic eyes. The SiO–retina contact area and shear stress were calculated by computational fluid dynamics. Methods A numerical model of an emmetropic eye and a myopic eye with and without scleral band underwent a saccade of 50°/0.137 s. The vitreous chamber surface was divided into superior and inferior 180° sectors: lens, pre-equator, post-equator, and macula. SiO–retina contact was evaluated as a function of fill percentages between 80% and 90% for standing, 45° upward tilt, and supine patients. Maximum and average shear stress were calculated. Results Overall, SiO–retina contact ranged between 40% and 83%; fill percentage varied between 80% and 95%. Neither the encircling scleral band nor the staphyloma significantly affected the SiO–retina contact area, although the presence of a scleral band proved disadvantageous when gazing 45° upward. The inferior retina–SiO contact remained below 40% despite 95% SiO fill. The SS significantly increased at the scleral band indentation and decreased elsewhere. The staphyloma greatly reduced shear stress at the macula. Conclusions The presence of a myopic staphyloma reduces shear stress at the macula but does not alter SiO–retina contact significantly. The apposition of a 360° scleral band may reduce SiO–retina contact at least in some postures and increases the SS at the indentation. Translational Relevance Assessing SiO–retina contact when vitreous chamber geometry changes according to pathologic or iatrogenic modifications allows accurate prediction of real-life tamponade behavior and helps explain surgical outcomes.
Collapse
Affiliation(s)
- Tommaso Rossi
- IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | | | | | | | - Guido Ripandelli
- IRCCS Fondazione G.B. Bietti per lo Studio e la Ricerca in Oftalmologia ONLUS, Rome, Italy
| |
Collapse
|
8
|
Farahvash A, Marafon SB, Juncal VR, Figueiredo N, Ramachandran A, Muni RH. Impact of tamponade agent on retinal displacement following pars plana vitrectomy for rhegmatogenous retinal detachment repair: a computer simulation model. Acta Ophthalmol 2022; 100:e1470-e1478. [PMID: 35257484 DOI: 10.1111/aos.15118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 01/27/2022] [Accepted: 02/18/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Armin Farahvash
- Faculty of Medicine University of Toronto Toronto Ontario Canada
| | - Samara B. Marafon
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
- Department of Ophthalmology St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada
| | - Verena R. Juncal
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
- Department of Ophthalmology St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada
| | - Natalia Figueiredo
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
- Department of Ophthalmology St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada
| | - Arun Ramachandran
- Department of Chemical Engineering and Applied Chemistry University of Toronto Toronto Ontario Canada
| | - Rajeev H. Muni
- Department of Ophthalmology and Vision Sciences University of Toronto Toronto Ontario Canada
- Department of Ophthalmology St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada
- Kensington Vision and Research Institute Toronto Ontario Canada
| |
Collapse
|