Thesis (M.A.)--Northern Kentucky University, 2008. / Made available through ProQuest. Publication number: AAT 1450346. ProQuest document ID: 1490080981. Includes bibliographical references (p. 36-40)

PURPOSE: To investigate relationships between preoperative and intraoperative characteristics with outcome variables in patients suffering from primary rhegmatogenous retinal detachment (RRD) or traction retinal detachment (TRD) complicated by serous choroidal detachment (CD). Choroidal detachment is a rare complication of retinal detachment and the current literature cites generally poor visual outcome variables. By investigating a retrospective case series, we hope to elucidate new relationships and embolden existing ones so that future physicians can make more educated decisions regarding the care for these complicated patients. METHODS: A retrospective case series analyzed 18 patient’s medical records (18 eyes) who had been diagnosed and surgically treated for RRD or TRD associated with a CD at the Longwood Medical Eye Center at Beth Israel Deaconess Medical Center. Patients with RDCD who had undergone 23-gauge pars plana vitrectomy with silicone oil tamponade were selected. Exclusionary criteria included ocular complications such as phthisis bulbi and open globe trauma. Patients experienced a variety of surgical procedures including by not limited to relaxing retinotomy (n=12 eyes), choroidal drainage (n=10 eyes), endoscopy-assisted PPV (n=10 eyes), and ERM peeling (n=8 eyes). Primary outcome variables tabulated were primary and final anatomic success, defined as successful reattachment of the retina to the underlying choroid, and final visual acuity. RESULTS: The mean age of the sample group was 69 with 8 patients (44%) diagnosed with preoperative hypotony (IOP <= 6 mmHg). A total of 12 patients were pseudophakic (67%). With a mean follow-up of 21.6 months, patients exhibited expected visual outcomes with 6 patients (33%) improving visual acuity and 7 patients (39%) decreasing visual acuity. Final anatomic success was seen in 17 cases (94%). A significant correlation was found between decreased number of previous surgeries and better visual outcomes (change in BCVA). Another significant relationship correlates choroidal drainage with worse visual outcomes (change in BCVA). Finally, patients who received ERM peeling had better rates of primary anatomic success. CONCLUSION: The advanced age of the sample lends itself to increased risk for cataracts and thus pseudophakia. In addition, high rates of diabetes and macular degeneration follow. The pathophysiology of RDCD in relation to the risk factors of hypotony and macular holes is possibly based on the Starling forces and favorable fluid transudation into the suprachoroidal space. Although the outcomes of this study were similar to previous literature, the visual outcomes are still poor at best. Reducing the number of previous, invasive, ocular surgeries was seen to be correlated with better visual outcomes. In addition, performing ERM peels is seen to be correlated with improved rates of primary anatomic success. More research is required on the etiology of the disease process and a case-controlled longitudinal study may be helpful in determining more relationships with outcome variables.

Orientadores: Rodrigo Pessoa Cavalcanti Lira, Carlos Eduardo Leite Arieta / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T06:50:41Z (GMT). No. of bitstreams: 1 Takasaka_Iuuki_M.pdf: 2254339 bytes, checksum: 4a21730e60893b2777df71653d5f38c2 (MD5) Previous issue date: 2012 / Resumo: Introdução: O descolamento de retina regmatogênico (DRR), uma das causas de cegueira, tem uma incidência anual de cerca de 6,3 - 17,9/100.000 habitantes na população mundial, e se não tratado pode levar a cegueira devido a degeneração das camadas retinianas. O uso de introflexão em conjunto com as adesões coriorretinianas em torno da rotura retiniana forma a base do tratamento para muitos DRR simples. A crioterapia realizada para retinopexia intra-operatoria tem sido implicada no desenvolvimento de pucker macular e vitreorretinopatia proliferativa. Eliminar a crioterapia da cirurgia convencional de introflexão poderia não afetar o resultado do sucesso anatômico e melhorar a recuperação visual. Objetivo: O objetivo primário deste ensaio clínico randomizado foi comparar a taxa de reaplicação retiniana e secundariamente os resultados da acuidade visual em pacientes com DRR que se submeteram a cirurgia de introflexão escleral e retinopexia com a crioterapia intra-operatória versus fotocoagulação a laser pós-operatório (um mês após a cirurgia). Método: É um ensaio clínico aleatorizado, mascarado, realizado em um único centro, composto por 86 pacientes submetidos à cirurgia de introflexão escleral. Os pacientes foram aleatorizados para serem submetidos à cirurgia de introflexão escleral e retinopexia com crioterapia intraoperatória (criopexia) ou retinopexia com fotocoagulação a laser pós operatória de 30 dias (laserpexia) após o procedimento. O desfecho primário foi avaliar a taxa de reaplicação retiniana no seguimento pós-operatório em 1 semana. Os desfechos secundários foram avaliar as taxas de reaplicação retiniana, as taxas de reoperação, as taxas de complicações pós-operatórias e recuperação da acuidade visual, em 1 mês e 6 meses de seguimento pós-operatório. Resultados: Foram incluídos 86 olhos de 86 pacientes a serem submetidos introflexão escleral. A amostra foi constituída de 43 pacientes pertencentes ao grupo laserpexia e 43 pacientes atribuídos ao grupo criopexia. Os dados demográficos foram semelhantes nos dois grupos. A taxa de sucesso anatômico em 1 semana, 1 mês e 6 meses foram semelhantes nos dois grupos, respectivamente, 93% (40 pacientes), 100% e 100% no grupo criopexia e 95,3% (41 pacientes), 100% e 100% no grupo da laserpexia (P, respectivamente, 0,5; 1,0 e 1,0). Três pacientes do grupo criopexia e 2 do laserpexia foram submetidos a uma cirurgia adicional (vitrectomia via pars plana) após a falha primária em 1 semana de seguimento. As complicações pós-operatórias foram semelhantes nos dois grupos, com exceção do edema de pálpebras. A recuperação visual foi mais lenta no grupo da crioterapia. A diferença na AV após 6 meses não foi significativa. Conclusão: Em pacientes com descolamento de retina regmatogênico sem complicações, ambas as técnicas de retinopexia mostraram resultados anatômico e funcional satisfatórios. A opção por laserpexia oferece recuperação visual mais rápida com menos complicações, porém requer uma segunda intervenção e maior custo em relação a criopexia / Abstract: Introduction: Rhegmatogenous retinal detachment (RRD), one of causes of blindness, has an annual incidence of about 6.3 to 17.9/100.000 people in the world population, and if untreated can lead to blindness due to degeneration of the retinal layers. The use of scleral buckles combined with chorioretinal adhesions around the retinal tear forms the basis of treatment for many simple RRD. Cryotherapy for retinopexy performed intraoperatively has been implicated in the development of macular pucker and proliferative vitreoretinopathy. Eliminating cryotherapy of conventional surgery might not affect the outcome of anatomic success and improve visual recovery. Objective: The aim of this randomized clinical trial was to compare the rate of retinal reapplication and secondly the results of visual acuity in patients with rhegmatogenuos retinal detachment who underwent surgery with scleral buckle retinopexy and intraoperative cryotherapy versus laser photocoagulation postoperatively (one month after surgery). Method: A randomized, masked, performed in a single center, comprising 86 patients undergoing scleral buckle surgery. Patients were randomized to undergo surgery, scleral buckle retinopexy with cryotherapy and intraoperative (criopexy) or postoperative retinopexy with photocoagulation 30 days (laserpexy) after the procedure. The primary endpoint was to evaluate the rate of replication in retinal postoperative follow-up within 1 week. Secondary endpoints were to evaluate retinal reapplication rates, reoperation rates, rates of postoperative complications and recovery of visual acuity at 1 month and 6 months postoperative follow-up. Results: We included 86 eyes of 86 patients undergoing scleral buckle. The sample consisted of 43 patients belonging to the group laserpexy and 43 patients assigned to the group criopexy. Demographic data were similar in both groups. The anatomic success rate in 1 week, 1 month and 6 months were similar in both groups, respectively, 93% (40 patients), 100% and 100% in criopexy and 95.3% (41 patients), and 100% 100% in group laserpexy (P, respectively, 0.5, 1.0 and 1.0). Three patients of group criopexy and 2 of laserpexy underwent additional surgery (pars plana vitrectomy) after the primary failure at 1-week follow-up. The postoperative complications were similar in both groups, except for edema of the eyelids. The visual recovery was slower in the cryotherapy group. The difference in VA after 6 months was not significant. Conclusion: In patients with uncomplicated rhegmatogenuos retinal detachment, both techniques of retinopexy showed satisfactory anatomical and functional results. The choice of laserpexy offers faster visual recovery with fewer complications, but requires a second intervention and higher cost compared to criopexy / Mestrado / Oftalmologia / Mestre em Ciências Médicas

PURPOSE: Normobaric hyperoxia (NBH) has been shown in animal models of experimental retinal detachment (RD) to effectively prevent photoreceptor degeneration. Furthermore, choroidal hyperpermeability has been implicated in the disease pathophysiology. In this study, we studied the effects of 3-hours of 40% FIO2 NBH on photoreceptor morphology and visual acuity in patients with vision loss associated with active central serous chorioretinopathy (CSCR). MATERIALS and METHODS: A total of 8 patients with active unilateral CSCR received at least one 3-hour NBH (40% FIO2) session. Best corrected visual acuity (BCVA) as well as thickness of the central macula, subretinal fluid (SRF), photoreceptor layer (PL), and outer nuclear layer (ONL) were assessed. RESULTS: In patients with unilateral acute CSCR, 3 hours of 40% FIO2 NBH showed a trend towards improved vision, but no statistical differences were obtained for BCVA, CMT, SRF, PL, or ONL. CONCLUSIONS: Administration of 3-hours of NBH did not induce any measurable anatomic changes in the retina nor any significant changes in visual acuity. These results challenge the hypothesis of choroidal hyperpermeability in CSCR and suggest that additional or alternative pathologies contribute to this disease. / 2022-11-29T00:00:00Z

The vitreous cavity, the largest chamber of the eye, is delimited anteriorly by the lens and posteriorly by the retina and is filled by the vitreous humour. Under normal conditions the vitreous humour has the consistency of a gel, however, typically, with advancing age a disintegration of the gel structure occurs, leading to a vitreous liquefaction. Moreover, after a surgical procedure called vitrectomy the vitreous body may be completely removed and replaced by tamponade fluids. Besides allowing the establishment of an unhindered path of light from the lens to the retina, the vitreous also has important mechanical functions. In particular, it has the role of supporting the retina in contact to the outer layers of the eye, and of acting as a diffusion barrier for molecule transport between the anterior and the posterior segments of the eye. Studying the dynamics of the vitreous induced by eye rotations (saccadic movements) is important in connection of both the above aspects. On the one hand indications exist that the shear stress exerted by the vitreous on the retina may be connected with the occurrence of retinal detachment. On the other hand, if the vitreous motion is intense enough (a situation occurring either when the vitreous is liqueed or when it has been replaced with a uid after vitrectomy), advective transport may be by far more important than diffusion and may have complex characteristics. Advection has indeed been shown to play an important role in the transport phenomena within the vitreous cavity, but, so far, only advection due to the slow overall fluid ux from the anterior to the posterior segments of the eye has been accounted for, while fluid motion due to eye rotations, even if it is generally believed to play an important role, has been invariably disregarded. Some recent contributions have pointed out the importance of accounting for the real vitreous cavity shape in studying uid motion induced by eye rotations. Modelling the vitreous cavity as a deformed sphere, showed that the flow field displays very complex three- dimensional characteristics to which effective fluid mixing is likely to be associated. The purpose of the thesis is to model numerically the motion of the liqueed vitreous within the vitreous cavity induced by different eye movements. Create the model in the Comsol interface, compare the results with theoretical, experimental measurements and do some ow visualizations. Finally show the dependence of the streaming intensity from the amplitude of rotations and the Womersley number .

We illustrate here how a range of fluid and solid mechanics problems relevant to the human eye have been combined in a continuing PhD study. Anterior chamber flow, the solid mechanics of tonometry, the effects of scleral buckle surgery and the mechanics of retinal detachment are all discussed. Finally, a number of other aye problems that are amenable to a theoretical mechanics treatment are proposed.

Stable suspensions of superparamagnetic cobalt nanoparticles have been prepared in poly(dimethysiloxane) (PDMS) carrier fluids in the presence of poly[dimethylsiloxane-b-(3-cyanopropyl)methylsiloxane-b-dimethylsiloxane] (PDMS-PCPMS-PDMS) triblock copolymers as steric stabilizers. A series of the polysiloxane triblock copolymers with systematically varied molecular weights were prepared via anionic polymerization using LiOH as an initiator. These copolymers formed micelles in toluene or poly(dimethylsiloxane) (PDMS) carrier fluids and served as "nanoreactors" for thermal decomposition of the CO₂(CO)8 precursor. The nitrile groups on the PCPMS central blocks are thought to coordinate onto the particle surface, while the PDMS endblocks protrude into the reaction medium to provide steric stability. The particle size can be controlled by adjusting the cobalt to copolymer ratio. Ordered self-assemblies of these cobalt nanoparticles are observed when the dispersions are cast from toluene. Electron diffraction spectroscopy reveals that the cobalt nanoparticles have fcc crystal structures. TEM shows non-aggregated cobalt nanoparticles with narrow size distributions, which are evenly surrounded with copolymer sheaths. However, some degree of surface oxidation was observed over time, resulting in a decrease in magnetic susceptibility. Novel poly[dimethylsiloxane-b-methyltriethoxysilylsiloxane-b-(3-cyanopropyl) methylsiloxane-b-methyltriethoxysilylsiloxane-b-dimethylsiloxane] (PDMS-PMTEOS-PCPMS-PMTEOS-PDMS) pentablock terpolymers were prepared. These terpolymers could fill the dual role both as steric stabilizers for preparing stable cobalt nanoparticle dispersions and precursors for the particle coating process. Silica films coated on the particles surfaces were employed to prevent the surface oxidation of the nanoparticles. Specific saturation magnetic measurement indicates that coating the nanoparticles with silica thin films can effectively inhibit the oxidation process. / Ph. D.

In nature, cells are not randomly clustered to form tissues. The tissue is a more complicated system with functions that go beyond what any single cell type could accomplish. While studying single-cell mechanics and dynamics is relevant from an investigative point of view, this approach loses, or fail to gather information about the tissue. The tissue investigated in this study is the neurosensory retina which seeing as extension of the brain is a very convenient model for the central nervous system due to its accessibility. The retina is constantly subjected to different mechanical stresses from development to adulthood. Although the majority of the phenomena where mechanical stresses are involved are well-studied, the mechanics behind them is not well understood. However, knowledge about the ability of the retina to adjust to mechanical stresses is essential, for example, for improving retinal surgery. Establishing a method to mechanically probe the retina is a challenge due to the extremely delicate nature of this multilayered neural tissue and to the short-time survival ex vivo. The organotypic tissue culture is a powerful tool because it allows to maintain with high accuracy the complex multicellular anatomy and the microenvironment of the original tissue. One of the limitations of the organotypic culture techniques has been until recently due to the ability to use only post-natal/juvenile tissues for long-term culture. The importance of using adult tissue is incontestable when the investigation focuses on age-related pathologies such as vitreous shrinkage or macula degeneration. In this work, TiO2 nanotube arrays are presented as the innovative substrate for long-term organotypic culture of adult neural tissue. The retinal whole-mount of adult guinea pig and the brain slices of adult mouse were cultures for 14 days without showing any sign of edema or swelling. Furthermore, in order to study the behavior of the retinal tissue under shear stress new set-ups were designed. For the first time, the behavior of the retinal layers were observed showing that the retina does not act as an homogeneous material in response to an applied stress. The methods developed here can be used for future quantitative studies, to provide an exact knowledge of retinal biomechanics which will help retinal surgeons to optimize their methods.

Retina is a unique site in the human body where the microcirculation can be imaged directly and non-invasively, allowing us to study in vivo the structure and pathology of the human microcirculation. Retinal images can be quantitatively assessed with computerized imaging techniques, enabling us to measure several different quantitative traits derived from the retinal vasculature. Arterial and venular calibres are the most extensively studied traits of the retinal microvasculature and numerous epidemiological studies demonstrated promising associations with systemic and ocular diseases as well as with disease markers. However, there has been a lack of research into pathophysiological processes leading to retinal vascular signs, and how they link retinal microcirculation with coronary and cerebral microvasculature change. Information about genetic determinants underlying retinal vascular structure is therefore important for understanding the processes leading to microvascular pathophysiology. Two genome wide association studies have been published so far revealing four loci associated with retinal venular calibre and one locus with arteriolar calibre. Here the results from the genome-wide association analysis of 10 different retinal vessel traits in two population based cohorts are presented. Retinal images were measured in non-mydriatic fundus images from 808 subjects in the Orkney Complex Disease Study (ORCADES) and 390 subjects from the Croatian island of Korcula, using the semi-automated retinal vasculature measurement programme SIVA and VAMPIRE. Using pairwise estimates of kinship based on genomic sharing, heritability was calculated for each trait. Estimates of tortuosity measure and fractal dimensions present first published reports of heritability estimates for those traits. In addition correlation analysis with systemic risk factor was also completed, confirming already published results as well as revealing some new associations. A genome wide association analysis of retinal arteriolar width revealed a genome wide significant hit (1.8x10-7) in a region of chromosome 2q32 (within TTN gene). Replication was sought in a further independent Scottish population (LBC) and additional 400 retinal images were graded. The result did not replicate, however the direction of the effect was consistent and a larger sample size is required. Analysis of the remaining traits did not yield genome wide significant result,s and will also require larger sample sizes. Genetic analysis of a binary retinal trait was also explored in a case control study of retinal detachment, which is an important cause of vision loss. A two-stage genetic association discovery phase followed by a replication phase in a combined total of 2,833 RRD cases and 7,871 controls was carried out. None of the SNPs tested in the discovery phase reached the threshold for association. Further testing was carried out in independent case-control series from London (846 cases) and Croatia (120 cases). The combined meta-analysis identified one association reaching genome-wide significance for rs267738 (OR=1.29, p=2.11x10-8), a missense coding SNP and eQTL for CERS2 encoding the protein ceramide synthase 2. Additional genetic risk score, pathway analysis and genetic liability analysis were also carried out.

<p><span lang="EN-GB" style="font-size:12.0pt / font-family:&quot / Times New Roman&quot / ,&quot / serif&quot / mso-fareast-font-family:&quot / Times New Roman&quot / mso-ansi-language:EN-GB / mso-fareast-language: EN-ZA">Literature shows that cataracts are the leading cause of blindness globally and nationally. Retinal detachment has also been a substantial problem both globally and nationally. Both of these conditions are prevalent in patients of 50 years and older. The treatment for both conditions is for surgery to be performed. In the Western Cape the three leading hospitals do not have ophthalmic pre-operative and post-operative protocols<span style="mso-bidi-font-weight:bold">.</span>Review question:What are the best practices to manage pre-operative and post-operative nursing care in patients waiting for cataract and retinal detachment surgery? bjectives:1. To determine the best practice in pre-operative and post-operative care in patients who have undergone cataract and/or retinal detachment surgery regarding: health education offered by nurses, counselling to prevent psychological effects, and positioning to prevent physical complications. 2. To develop a framework based on systematic reviews for pre-operative and post-operative ophthalmic nursing care in South Africa. Methodology: </span><span lang="EN-GB" style="font-size: 12.0pt / font-family:&quot / Times New Roman&quot / ,&quot / serif&quot / mso-ansi-language:EN-GB">A systematic review using the guide by the Centre for Reviews and Dissemination was done, and <span style="mso-bidi-font-weight:bold">studies were </span>identified by searching various electronic databases and visually scanning reference lists from the relevant studies. Studies that were included were evidence-based. All study types were considered and the studies were selected based on the title and, where available, the abstract. These were then assessed against the inclusion criteria. A narrative synthesis was used. Finally the evidence was summarised and a framework was drawn up, focusing on pre-operative and post-operative nursing care for cataract and retinal detachment surgery</span></p> <p>&nbsp / </p>