However, this is by no means the limit. More knowledge on macular hole is needed. Continuous research in Hong Kong and other scientific communities are indispensable. A multicentre, multi-surgeon study should be contemplated and carried out prior to the generalization or application of this technique to all patients. / Over the last few years, we have collected essential clinical and laboratory data on indocyanine green (ICG) assisted internal limiting membrane (ILM) peeling in macular hole surgery in Hong Kong. With the intraoperative use of a small volume and low concentration of ICG, we have shown the usefulness and safety of this technique in improving the surgical outcomes, both antomically and functionally, in patients with macular hole of idiopathic type or in severely myopic eyes. Our randomized controlled trial demonstrated higher anatomical closure rate and better visual outcome with ICG assisted ILM peeling compared with no ILM peeling in primary idiopathic macular hole surgery. Our case-control study also demonstrated that ICG assisted ILM removal in macular hole surgery of severely myopic eyes gives promising anatomical closure rate and visual outcome comparable to emmetropic ones. / Kwok Kwan-ho. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 201-214). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.

Treatment of vision impairing diseases involves drug transport through the vitreous humor. Diffusion cells were used to measure macro-scale (mutual) diffusivity (Dm) to understand how solute size affects diffusion through the vitreous humor of rabbit and porcine eyes. Solutes examined included timolol maleate, dexamethasone sodium phosphate (DMSP), sodium fluorescein, and FITC-dextrans (4, 40, and 150kDa). Diffusivity was inversely dependent on solute size. The Dm's of small solutes in the vitreous were 30 – 65% of that in PBS, while the Dm's of large solutes were 40 – 60% of that in PBS. Extrapolations to the human eye produced similar results using diffusivities based on either species. We used Diffusion Ordered NMR Spectroscopy to measure micro-scale (self) diffusivity (Ds) of DMSP through vitreous humor. The Ds and Dm were significantly different in PBS, but similar in vitreous. A method for obtaining in vivo imagery and data of vitreous fluorophore distribution is also presented.

Treatment of vision impairing diseases involves drug transport through the vitreous humor. Diffusion cells were used to measure macro-scale (mutual) diffusivity (Dm) to understand how solute size affects diffusion through the vitreous humor of rabbit and porcine eyes. Solutes examined included timolol maleate, dexamethasone sodium phosphate (DMSP), sodium fluorescein, and FITC-dextrans (4, 40, and 150kDa). Diffusivity was inversely dependent on solute size. The Dm's of small solutes in the vitreous were 30 – 65% of that in PBS, while the Dm's of large solutes were 40 – 60% of that in PBS. Extrapolations to the human eye produced similar results using diffusivities based on either species. We used Diffusion Ordered NMR Spectroscopy to measure micro-scale (self) diffusivity (Ds) of DMSP through vitreous humor. The Ds and Dm were significantly different in PBS, but similar in vitreous. A method for obtaining in vivo imagery and data of vitreous fluorophore distribution is also presented.

The activity and wettability of raw fused silica capillary tubing was found to be widely variable which places severe limitations on the reproducibility of column deactivation and inertness. Hydrothermal treatment of the raw fused silica with nitric acid was proven to be very effective for cleaning and maximizing the degree of silanol coverage of the surface. The capillary rise method was used to obtain contact angle data for untreated fused silica and fused silica treated with a variety of deactivating reagents. This contact angle data was used in the construction of Zisman plots which allowed quantitative comparison of the wettability and degree of surface coverage obtained with the different deactivants. The thermal stability of the final column was related to the success of the deactivation procedure. The choice of cross-linking initiator was also found to have an affect on column inertness. In the synthesis of intermediate polarity polysiloxane stationary phases, mixtures of commercially available cyclic siloxanes were shown to be a viable alternative to the use of dichlorosilanes as starting material. The main advantages were the simplification of the synthesis procedure, simpler and better molecular weight control of the polymer, and the elimination of HC1 as a by-product of both the polymerization and endcapping steps. A new stationary phase, 7% cyanoethyl, 7% phenyl, 1% vinyl, methyl polysiloxane was synthesized and found to be more polar than OV-1701 with higher temperature stability, easily cross-linked, and suitable for use in supercritical fluid chromatography. / Ph. D.

The purpose of this study was to quantify the effects of phacoemulsification and posterior segment chamber lens placement on vitreous inflammatory and neovascular growth factors. More specifically, the effect of immediately preceding cataract surgery was compared to a history of cataract surgery. This study involved a retrospective review and analysis of vitreous samples from a total of twenty seven patients separated into three groups. Group 1, seven patients who underwent a pars plana vitrectomy with macular surgery, group 2, fourteen patients who underwent a combined cataracts and pars plana vitrectomy procedure and group 3, six patients with a history of cataract surgery who underwent a pars plana vitrectomy. The twenty seven patients were picked from a pool of 100 patients who all received pars plana vitrectomy at Beth Israel Deaconess Medical Center with surgeon Dr. Jorge Arroyo. Exclusion factors included active ocular pathologies such as vitreous hemorrhage and retinal detachment. Undiluted vitreous samples from each group were taken before beginning the pars plana vitrectomy. The vitreous samples were analyzed for concentrations of fourteen specific vitreous cytokines and neovascular growth factors including but not limited to TNF Alpha; and SCD40L. These fourteen cytokines and growth factors were chosen through a literature review on the post-surgery ocular inflammatory response. Statistical analysis was done on the average means of the cytokine levels for each group using SPSS 20 for windows. A comparison of means analysis found no significant difference in the means of the fourteen cytokines for group 1 and group 2. A second comparison of means with a pooled control group of both group 1 and group 2 patients versus group 3 was also run. In this analysis, only SCD40L or soluble CD40 ligand was shown to have a significant difference between groups. SCD40L levels were significantly higher (significance level of .038) in group 3, the history of cataract group with a mean of (9.50±4.76) than in the control group with a mean of (5.50±3.35). The findings of this study indicate that the protein SCD40L may play an important role in mediating the inflammatory response seen post cataract surgery and may be useful as a target for novel therapies against the inflammatory response.

No description available.

My PhD research involves multi-disciplinary areas of study such as measuring perfusion of blood vessels in hamster dorsal skin using laser speckle imaging technique. In this study the changes were measured in blood flow velocity and diameters of micro vasculatures after the influence of glycerol application. The second study identifies the changes in morphology and optical properties of eye tissue after applying hyper-osmotic agent such as 100% anhydrous glycerol. Further investigation on the reversal process was performed without any application of 0.9% saline. The third study identified the variation in fluorescence in hamster dorsal skin tissue and enucleated porcine eyes with temperature. This study investigated the variation in fluorescence intensity with temperatures starting at 14°C and compared in vivo and in vitro results for consistency. The fourth study investigated an implantable drug delivery package that was fabricated using PMMA and implanted between the sub-conjunctival and super-scleral space and release the content of the device by either mechanical pressure or light-activated ophthalmic Nd:YAG laser after optically clearing the eye tissue by topical application of a hyper-osmotic agent, 100% anhydrous glycerol. A hyper-osmotic agent creates a transport region in the conjunctiva and sclera to get visual access of the compartments in the drug delivery package. This new technology would provide the option to the patient of one time implantation of the carrier system containing the drug. Each time the patient requires medication a ND-YAG or other laser beam will propagate through the cleared eye tissue to release the drug in measurable doses at the discretion of the doctor from the package directly in to the vitreous humor. In this study we have measured half-life of the dye in the vitreous humor or posterior chamber and biocompatibility. The last study had drawn distinction between the fluorescence signals based on the location (anterior or posterior chamber) of the 10% Na fluorescence dye in the in vivo rabbit and ex vivo pig eyes. / text

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

No description available.

Thesis (Ph. D.)--School of Pharmacy and Dept. of Chemistry. University of Missouri--Kansas City, 2004. / "A dissertation in pharmaceutical sciences and chemistry." Advisor: Ashim K. Mitra. Typescript. Vita. Description based on contents viewed Feb. 22, 2006; title from "catalog record" of the print edition. Includes bibliographical references (leaves 156-188). Online version of the print edition.