Silicone Oil for the management of complicated retinal detachments was introduced by Cibis and associates . Its clinical use was later prohibited in the United States because of significant post-operative complications. Experimental studies indicated that silicone oil might be retino toxic. Scott 2 in Cambridge, for many years continued to advocate the use of Silicone Oil and he slowly convinced retinal surgeons that there might be a place for Silicone Oil in detachment s u r g e r y . Because of a better understanding of vltreoretinal abnormalities and improved surgical techniques, the use of Silicone Oil is now being re-evaluated in many centres including the United States.

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.

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In an effort to understand the resuspension phenomena, interactions of spherical micro-meter particles (glass beads (GB) and Stainless steel (SS)) were investigated experimentally on different surfaces (glass, ceramic, hardwood, metal and chemical agent resistant coated metal (CARC)). Particles were deposited on the lower surface of a 10 cm square wind tunnel by gravitational settling. Air flows were imposed from an open entrance at average velocities up to 16 m/s. Individual particle trajectories obtained by high-speed imaging reveal three different types of motion: rolling/bouncing, immediate liftoff and complex motion. Surface roughness significantly affects the particle initial motion prior to liftoff. The majority of particle trajectories from the glass substrate were parallel to the surface with complex motion, covering 25% of the total distance traveled in rolling/bouncing motion before liftoff. Hardwood substrates took the longest time for initial particle movement (t >1 s) causing a more rapid liftoff. The ceramic substrate showed the most rolling/bouncing motion, for 80% of the particles. Additionally, single layer detachment showed that the detachment percentage initially follow an exponentially increasing trend for a period of ~ 1 s, followed by a plateau phase for a period of 5 s. Changing velocity, substrate and particle size significantly affects GB particle detachment. Furthermore, detachment from the metal substrate was consistently higher than the CARC substrates. However, particle density is not a significant difference in the bigger particle size studied. Initial 3-D particle tracking showed that particles seem to travel in a constant angle to the left rather than going straight in the flow direction. A detachment mode model showed that the detachment by direct liftoff required a much higher speed than rolling motion with a minimum of 14 m/s for both GB70 and SS70 on glass and metal surface, and the velocity increased to 21 m/s for the smaller particle. Incorporating the different types of particle motion prior to liftoff into resuspension models, and how their relative contributions change with different particle and substrate materials, can potentially yield improved predictive capabilities.

The Weepah Hills Area (Nevada) exposes exhumed metamorphic and plutonic rocks and upper-plate (supradetachment) volcano-sedimentary rocks that have experienced a complex, multi-stage deformational and depositional history. The Weepah Hills metamorphic core complex (WHMCC) is located in a region of the western Cordillera that was affected by both Miocene Basin-and-Range style E-W extension and Mio-Pliocene Walker Lane transcurrent shearing. Mio-Pliocene transcurrent deformation is transferred across a ~175 km releasing bend, known as the Mina Deflection, that kinematically links dextral strike-slip faults of the Death Valley-Fish Lake Valley with the central Walker Lane Belt. Progressive Mio-Pliocene transtension is characterized by core complex detachment faulting and younger high-angle normal faults. Timing of detachment faulting is constrained by both (U-Th)/He thermochronometry of footwall rocks and detailed chronostratigraphy of upper-plate strata to between 9-6 Ma. This age is supported by deformation recorded in the upper-plate strata that is attributed to progressive folding of the detachment associated with corrugation development. Earlier Miocene Basin-and-Range style extension is characterized by N-S trending high-angle normal faults and half-grabens that are strongly overprinted by Mio-Pliocene structures. (U-Th)/He zircon cooling ages from the detachment footwall range from ~12-20 Ma and are attributed to exhumation and unroofing related to E-W Basin-and-Range extension. New detailed sedimentological and geochronologic data show that, in contrast to previous research, the WHMCC upper-plate strata do not form a single supradetachment package, but rather three temporally distinct Miocene stratigraphic packages bounded by angular unconformities. The stratigraphic, structural, and exhumational record preserved in the WHMCC elucidates the timing of deformation and sedimentary basin evolution related to both Basin-and-Range E-W extension and Walker Lane related NW-directed transtension. / text

Primary rhegmatogenous retinal detachment (RRD) is one of the most common ophthalmic emergencies. RRD is caused by a full thickness break in the retina which initiates separation of the neurosensory retina from the underlying retinal pigment epithelium. The subsequent accumulation of fluid within this potential space extends the area of detachment and causes visual loss. Previous assessments of RRD incidence have demonstrated large differences in case definition and methodology, with incidence estimates varying 3-fold geographically and in different time periods. To date there have been no systematic or prospective incidence estimates of primary RRD in the U.K. In this thesis I present the findings of a 2-year epidemiology study that prospectively aimed to recruit all incident cases of primary RRD diagnosed in Scotland. Case recruitment from consenting participants comprised a detailed questionnaire and a blood sample. In this thesis, I present the findings of the Scottish retinal detachment study that examined the incidence, demographic features, temporal incidence trends, as well as clinical and socio-economic associations of primary RRD in Scotland. From the clinical and genetic resource I assembled, I calculated the first population based estimate of the sibling recurrence risk ratio for RRD and designed and assisted in the analysis of the first case-control genome wide association study of this condition. Results from this study have estimated the annual incidence of primary RRD in Scotland to be 12.05 per 100,000 population. Based on this estimate, there are approximately 7,300 new cases annually in the United Kingdom. RRD incidence increases with age, is more common in men and right eyes, and is strongly associated with socio-economic affluence. In addition, using hospital episode data, the overall age-standardised incidence of RRD in Scotland was shown to be steadily increasing since 1987 with an average annual increase of 1.9%. Analysis of the clinical findings highlighted that the majority of RRD cases are caused by more than one retinal break; an important consideration for appropriate surgical management. Ocular trauma, previous cataract surgery, family history, and retinal degeneration are important predisposing features. In addition, over a 2 year period approximately 7% of individuals will suffer a RRD in the fellow eye representing an important risk of bilateral visual loss. Furthermore, I demonstrate that the risk of having an affected sibling with RRD is increased 2-fold given that one sibling has had the condition, substantiating a genetic component to the pathogenesis of this condition. In the final aspect of this thesis I will present the design and analysis of a two stage case-control genome-wide association study examining the role of common genetic variants and selected candidate genes in predisposing to RRD development.

The work presented in thesis is part of the DANIELA project which aims to replace the current air data system on civil aircrafts with a flush mounted Air Data System (ADS) built around a 3 axis Doppler LIDAR function as the primary data channel. This thesis is focused on the comparison of different window materials and their optical clarity by means of theoretical and experimental analysis. Four different window materials including BK7, Sapphire, Germanium and ZnS are placed in a wind tunnel. The samples are each exposed to flows of air and water for specific periods of time during which temperature, pressure and air speed are recorded. Subsequently, each sample is carefully observed under the microscope. This is followed by the measurement of the amount of back scatter via detecting the change in the voltage once it is placed in the optical station. The optical tests reveal the amount of dust adhered to the samples which results in increased voltage. Review of these samples under the microscope matches the results obtained from the optical test. The two sets of data obtained from the two tests determined that some samples collected more dust in comparison to others. It was established that under identical test conditions i.e. flow, temperature and moisture, BK7 and Sapphire collect considerably less dust compared to ZnS. Moreover it was impossible to test Germanium sample optically, under a microscope as it is a dark opaque glass.

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