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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Micro/nano fabrication of polymeric materials by DMD-based micro-stereolithography and photothermal imprinting

Lu, Yi, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
172

Outcome after surgery of congenital cataract /

Lundvall, Anna, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. Inst., 2002. / Härtill 5 uppsatser.
173

Toughening polymer surfaces

Ali, Haider K. January 2006 (has links)
Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 205-210.
174

Therapeutic contact lenses for comfort molecules

Ali, Maryam, Byrne, Mark E. January 2007 (has links)
Thesis--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (p.107-118).
175

Experimental study and numerical analysis of compression molding process for manufacturing precision aspherical glass lenses

Jain, Anurag, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 167-175).
176

Quantitative acoustic microscopy of surfaces

Rowe, John M. January 1987 (has links)
No description available.
177

Análise de qualidade óptica e performance visual em olhos implantados com lentes intraoculares asféricas neutras / Implantation of an aspherical intraocular lens

Marcony Rodrigues de Santhiago 05 October 2012 (has links)
Objetivo: Determinar se o implante de uma determinada lente intraocular asférica resulta em redução das aberrações oculares e melhora da qualidade ótica e sensibilidade ao contraste sem que ocorra redução critica da profundidade de foco. Desenho: Estudo prospectivo, duplo-cego, randomizado. Métodos: Este estudo que incluiu 25 pacientes com catarata bilateral, uma LIO asférica foi implantada em um olho e uma LIO esférica no olho contralateral. Aberrações de maior ordem e parâmetros de qualidade ótica foram obtidos através de aberrômetro de retinoscopia dinâmica, 1 e 3 meses apos a cirurgia. Foi também medido a acuidade visual com e sem correção e a sensibilidade ao contraste. Acuidade visual para perto e distancia intermediaria foi obtida como forma de medida da profundidade de foco. Resultados: Não houve diferença estatisticamente significativa entre os grupos para acuidade visual corrigida e não corrigida 1 e 3 meses apos a cirurgia. Houve diferença estatisticamente significativa entre os grupos quanto a sensibilidade ao contraste sob condições fotópticas na frequência espacial de 12 ciclos por grau e sob condições mesópicas em todas as frequências espaciais estudadas. O grupo com a LIO Akreos AO obteve menores valores de aberrações de maior ordem totais e de aberração esférica com pupilas de 5 e 6 mm e melhores valores de qualidade ótica comparado ao grupo com LIO Akreos Fit (p <0.05). Não houve diferença significativa entre os grupos quando se investigou visão de perto e intermediaria corrigido para longe. Conclusões: A LIO asférica Akreos AO induziu menos aberrações de maior ordem além de produzir melhores parâmetros de qualidade ótica com melhores resultados de sensibilidade ao contraste em condições mesópicas sem redução critica de profundidade de foco quando comparado a LIO esférica Akreos Fit. / PURPOSE: To determine whether implantation of an aspherical intraocular lens (IOL) results in reduced ocular aberrations and improved optical quality and contrast sensitivity after cataract surgery without critical reduction of depth of focus. DESIGN: Double-blinded, randomized, prospective study. METHODS: In an intraindividual study of 25 patients with bilateral cataract, an aspherical IOL (Akreos Advanced Optic [AO]; Bausch & Lomb, Inc., Rochester, New York, USA) was implanted in one eye and a spherical IOL (Akreos Fit; Bausch & Lomb, Inc) in the fellow eye. Higher-order aberrations with a 5- and 6-mm pupil and optical quality parameters were measured with a dynamic retinoscopy aberrometer at 1 and 3 months after surgery. Uncorrected and best-corrected visual acuity and contrast sensitivity under mesopic and photopic conditions also were measured. Distancecorrected near and intermediate visual acuity were studied as a measurement of depth of focus. RESULTS: There was no statistically significant difference between eyes in uncorrected and best-corrected visual acuity at 1 and 3 months after surgery. There was a statistically significant between-group difference in contrast sensitivity under photopic conditions at 12 cycles per degree and under mesopic conditions at all spatial frequencies. The Akreos AO group obtained statistically significant lower values of higher-order aberrations and spherical aberration with 5- and 6-mm pupils and better optical quality parameters compared with the Akreos Fit group (P < .05). There was no significant difference in distance-corrected near and intermediate visual acuity between both groups. CONCLUSIONS: Aspherical aberration-free Akreos AO IOL induced significantly less higher-order aberrations and spherical aberration than the Akreos Fit. Contrast sensitivity under mesopic conditions and optical quality parameters were better with the Akreos AO with similar results of depth of focus.
178

Lente intraocular suplementar Sulcoflex® Multifocal : análise dos resultados e complicações / Sulcoflex® Multifocal intraocular lens : analysis of clinical results and complications

Bisneto, Otavio Siqueira, 1974- 23 August 2018 (has links)
Orientador: Carlos Eduardo Leite Arieta / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T07:26:52Z (GMT). No. of bitstreams: 1 Bisneto_OtavioSiqueira_D.pdf: 1957765 bytes, checksum: 2b131f1ff863d58643b8b214c93cb0cf (MD5) Previous issue date: 2013 / Resumo: Objetivo: avaliar os resultados clínicos e possíveis complicações do implante da lente intraocular (LIO) Sulcoflex® Multifocal. Material e Método: realizou-se estudo tipo série de casos de indivíduos submetidos ao implante bilateral da LIO Sulcoflex® Multifocal no Hospital de Olhos do Paraná (Curitiba - Brasil). Foram incluídos indivíduos previamente operados de catarata, submetidos ao implante bilateral da LIO Sulcoflex® Multifocal, no período de julho de 2010 a janeiro de 2012, sendo os principais critérios de inclusão presença de LIO monofocal não acomodativa implantada no saco capsular de ambos os olhos e acuidade visual corrigida ou não de 20/25 ou melhor em ambos os olhos e os principais critérios de exclusão presença de doença ocular associada e refração cilíndrica maior que 0,75 D negativa ou esférica maior que 3 D positivas ou negativas. Foram estudadas as seguintes variáveis: acuidade visual para longe e para perto com e sem correção óptica; grau de refração esféro-cilíndrica; pressão intraocular; contagem de células endoteliais; aberrações ópticas de alta ordem; sensibilidade ao contraste e complicações intra e pós-operatórias. Todas as cirurgias foram realizadas pelo mesmo cirurgião, sob anestesia tópica, com implante da LIO por incisão de 2,75mm, objetivando se a emetropia. Resultados: foram avaliados 16 olhos de 8 indivíduos. A idade média foi de 63.87±7,1 anos variando de 55 a 79 anos. O tempo médio de seguimento foi de 11,37 +- 1,4 meses variando de 10 a 14 meses. Houve piora de 1 linha da acuidade visual para longe sem correção óptica em 7 olhos (43,7%), e melhora da acuidade visual de perto com todos os olhos apresentando J2 ou melhor sem correção óptica. Conclusão: após o implante da LIO Sulcoflex® Multifocal houve melhora da acuidade visual de perto sem correção óptica, e diminuição da acuidade visual de longe com e sem correção óptica, e da sensibilidade ao contraste em 2 das 5 frequências espaciais estudadas. A abertura invertida (face anterior voltada posteriormente) de uma lente no momento do implante ocasionou perda significativa de células endoteliais neste olho / Abstract: Purpose: to evaluate the clinical results and possible complications of the Sulcoflex® Multifocal intraocular lens implantation. Methods: It was conducted a case series study of patients undergoing IOL Sulcoflex® Multifocal bilateral implantation at Paraná Eye Hospital (Curitiba - Brazil). It were included patients previously operated for cataract, underwent bilateral implantation of IOL Sulcoflex® Multifocal, from July 2010 to January 2012, being the main inclusion criteria, presence of monofocal no accommodative IOL implanted in capsular bag in both eyes and best corrected or not visual acuity 20/25 or better in both eyes; the main exclusion criterias were presence of eye disease, cylindrical refraction greater than -0.75 diopters or greater than 3 positive or negative spherical diopters. It were studied the following variables: visual acuity for near and distance vision with and without optical correction; degree of sphero-cylindrical refraction, intraocular pressure, endothelial cell count, high-order aberrations, contrast sensitivity and intra and postoperative complications. All surgeries were performed by the same surgeon, under topical anesthesia with IOL implant incision by 2.75 mm, with the target of emmetropia. Results: It was evaluated 16 eyes of 8 persons. The mean age was 63,87 +- 7,1 years, ranging from 55 to 79 years. The mean follow up was 11,37 +- 1,4 months, ranging from 10 to 14 months. It was observed decreased of 1 line in distance visual acuity without correction in 7 eyes (43,7%), and improvement of near visual acuity, with all eyes J2 or better without correction. Conclusion: after Sulcoflex® Multifocal IOL implantation, the near vision without correction was improved, the far vision with and without correction was decreased, and contrast sensitivity was decreased in 2 of 5 spatial frequencies studieds. The reverse opening (anterior facing back) of one IOL at the time of implantation caused a significant loss of endothelial cells in this eye / Doutorado / Oftalmologia / Doutor em Ciências Médicas
179

Air lens vs aspheric surface: a lens design case study

Gao, Weichuan, Sasian, Jose 27 November 2017 (has links)
We discuss the behavior of air lenses in lens design. The structural aberration coefficients of a thin air lens are derived and compared with their glass thin lens counterpart. Examples are provided for a telephoto lens and the Monochromatic Quartet where air lenses or aspheric surfaces are used.
180

Dental pulp stem cells : investigations into methods of enhancing regeneration and repair of the cornea

Kushnerev, Evgeny January 2016 (has links)
The cornea is the transparent, avascular and highly innervated outer anterior layer of the eye. The cornea is a very delicate structure and any traumatic insult may lead to damage and limbal stem cell deficiency (LSCD), leading to chronic discomfort, visual impairment and ultimately blindness. The resultant issues can have a significant effect on patients and reduce their quality of life. Whilst conservative and therapeutic management of these problems play a part in the treatment of corneal injuries often surgery is indicated. However, surgical repair of damaged corneas may be limited by the availability of suitable donor tissue and donor site morbidity. Corneal grafts or penetrating keratoplasty (PK) or donor limbal grafts may lead to surgical complications such as corneal scarring, infection and graft rejection. First described in 1908 by A. Maximow, stem cells offer the opportunity to produce functional cell specific tissues from undifferentiated “primordial” cells. By using stem cells from human adult or deciduous tooth pulp, repair and regeneration of the cornea may be possible. Furthermore, it may lead to development of new and innovative treatments of other corneal disorders and injuries. The aim of the investigations detailed in this thesis was to characterize dental pulp stem cells (DPSC), help establish their use in regenerative medicine and help enhance the repair and regeneration of damaged corneal epithelium. Using various laboratory techniques including PCR, western blot and immunostaining it was determined that DPSC possess adequate potency and plasticity to be differentiated into a number of cell-lines. Co-culture of DPSC with human cornea demonstrated that stem cells were attracted to the tissue and migrate towards it and attach to the surface of the limbal explant. Additionally, using soft contact lenses it has been shown that DPSC can be successfully transferred from culture to human cornea in vitro. Expression of terminally differentiated corneal epithelium markers such as cytokeratin 3 & 12 further supports the concept that DPSC were transdifferentiated into epithelial progenitor cells. Once transferred onto the corneal surface, DPSC supported corneal epithelium regeneration, allowed corneal epithelial like cells to grow and avert conjunctivalisation and thus maintained cornea transparency. Further studies are needed to provide a better understanding of the DPSC’s role in corneal regeneration, but it is clear that DPSC are promising candidates for this novel and non-invasive method of corneal epithelium regeneration.

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