Objetivos: Comparar as alterações de espessura das camadas da retina macular adquiridas com tomografia de coerência óptica (TCO) e as amplitudes das ondas de eletrorretinograma multifocal (ERGmf) convencional e com estímulo lentificado entre olhos com hemianopsia temporal sequelar por compressão quiasmática e controles saudáveis, além de avaliar as correlações entre TCO, ERGmf e campo visual (CV) central. Métodos: Quarenta e três olhos (30 pacientes) com hemianopsia temporal sequelar por tumores hipofisários previamente submetidos a descompressão quiasmática e 37 olhos saudáveis (19 controles) foram submetidos a TCO-DS da mácula, ERGmf e CV tipo 10-2. Após segmentação, foram medidas as espessuras maculares da camada de fibras nervosas da retina (CFNR), camada de células ganglionares (CCG), camada plexiforme interna (CPI), camada nuclear interna (CNI), camada plexiforme externa (CPE), camada nuclear externa (CNE) e camada de fotorreceptores (CFR). Amplitudes e potenciais oscilatórios (PO) multifocais foram adquiridos com o ERGmf convencional e com estímulo lentificado, respectivamente, analisados em valores médios por quadrantes e hemicampos. Resultados: Espessuras da CFNR, CCG e CPI foram significantemente menores em todos os quadrantes, enquanto CNI, CPE e CFR tiveram medidas significantemente maiores nos quadrantes nasais nos pacientes comparados com os controles. Correlações significantes entre a TCO e os valores de CV 10-2 foram positivas para CFNR, CCG e CPI, e negativas para CNI, CPE e CFR. As amplitudes médias dos POs e de N1 do ERGmf se mostraram significantemente reduzidas na hemirretina nasal dos pacientes. Correlações significantes foram encontradas entre as amplitudes de PO e ERGmf para com medidas de TCO da hemirretina nasal interna e externa, respectivamente. Conclusões: Pacientes com hemianopsia temporal sequelar por compressão quiasmática previamente tratada apresentam adelgaçamento significante de CFNR, CCG e CPI e espessamento de CNI, CPE e CFR, associados com amplitudes reduzidas de PO e N1, sugerindo que o dano axonal à retina interna desencadeia lesão secundária das camadas externas da retina nesta condição / Purpose: To compare optical coherence tomography (OCT)-measured macular retinal layers in eyes with permanent temporal hemianopia from chiasmal compression and controls, compare regular and slow-flash multifocal electroretinography (mfERG) in patients and controls, and assess the correlation between OCT, mfERG and central visual field (VF) data. Methods: Forty-three eyes (30 patients) with permanent temporal hemianopia from pituitary tumors previously submitted to chiasm decompression and 37 healthy eyes (19 controls) were submitted to macular SD-OCT, mfERG and 10-2 VF testing. After segmentation, macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL) and photoreceptor layer plus (PRL+) thickness was measured. Amplitudes and oscillatory potentials (OP) were measured on regular and slow-flash mfERG, respectively, and expressed as mean values per quadrant and hemifield. Results: RNFL, GCL and IPL thickness measurements were significantly reduced in all quadrants while INL, OPL and PRL were significantly increased in the nasal quadrants in patients compared to controls. Significant correlations between OCT and 10-2 SAP measurements were positive for RNFL, GCL and IPL and negative for INL, OPL and PRL. OPs and mfERG N1 amplitudes were significantly reduced in the nasal hemiretina of patients. Significant correlations were found between OP and mfERG amplitudes for inner and outer nasal hemiretina OCT measurements, respectively. Conclusions: Patients with permanent temporal hemianopia from previously treated chiasmal compression displayed significant RNFL, GCL, IPL thinning and INL, OPL and PRL thickening associated with reduced OP and mfERG N1 amplitudes, suggesting axonal injury to the inner retina leads to secondary damage to the outer retina in this condition

Objetivos: Comparar as alterações de espessura das camadas da retina macular adquiridas com tomografia de coerência óptica (TCO) e as amplitudes das ondas de eletrorretinograma multifocal (ERGmf) convencional e com estímulo lentificado entre olhos com hemianopsia temporal sequelar por compressão quiasmática e controles saudáveis, além de avaliar as correlações entre TCO, ERGmf e campo visual (CV) central. Métodos: Quarenta e três olhos (30 pacientes) com hemianopsia temporal sequelar por tumores hipofisários previamente submetidos a descompressão quiasmática e 37 olhos saudáveis (19 controles) foram submetidos a TCO-DS da mácula, ERGmf e CV tipo 10-2. Após segmentação, foram medidas as espessuras maculares da camada de fibras nervosas da retina (CFNR), camada de células ganglionares (CCG), camada plexiforme interna (CPI), camada nuclear interna (CNI), camada plexiforme externa (CPE), camada nuclear externa (CNE) e camada de fotorreceptores (CFR). Amplitudes e potenciais oscilatórios (PO) multifocais foram adquiridos com o ERGmf convencional e com estímulo lentificado, respectivamente, analisados em valores médios por quadrantes e hemicampos. Resultados: Espessuras da CFNR, CCG e CPI foram significantemente menores em todos os quadrantes, enquanto CNI, CPE e CFR tiveram medidas significantemente maiores nos quadrantes nasais nos pacientes comparados com os controles. Correlações significantes entre a TCO e os valores de CV 10-2 foram positivas para CFNR, CCG e CPI, e negativas para CNI, CPE e CFR. As amplitudes médias dos POs e de N1 do ERGmf se mostraram significantemente reduzidas na hemirretina nasal dos pacientes. Correlações significantes foram encontradas entre as amplitudes de PO e ERGmf para com medidas de TCO da hemirretina nasal interna e externa, respectivamente. Conclusões: Pacientes com hemianopsia temporal sequelar por compressão quiasmática previamente tratada apresentam adelgaçamento significante de CFNR, CCG e CPI e espessamento de CNI, CPE e CFR, associados com amplitudes reduzidas de PO e N1, sugerindo que o dano axonal à retina interna desencadeia lesão secundária das camadas externas da retina nesta condição / Purpose: To compare optical coherence tomography (OCT)-measured macular retinal layers in eyes with permanent temporal hemianopia from chiasmal compression and controls, compare regular and slow-flash multifocal electroretinography (mfERG) in patients and controls, and assess the correlation between OCT, mfERG and central visual field (VF) data. Methods: Forty-three eyes (30 patients) with permanent temporal hemianopia from pituitary tumors previously submitted to chiasm decompression and 37 healthy eyes (19 controls) were submitted to macular SD-OCT, mfERG and 10-2 VF testing. After segmentation, macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL) and photoreceptor layer plus (PRL+) thickness was measured. Amplitudes and oscillatory potentials (OP) were measured on regular and slow-flash mfERG, respectively, and expressed as mean values per quadrant and hemifield. Results: RNFL, GCL and IPL thickness measurements were significantly reduced in all quadrants while INL, OPL and PRL were significantly increased in the nasal quadrants in patients compared to controls. Significant correlations between OCT and 10-2 SAP measurements were positive for RNFL, GCL and IPL and negative for INL, OPL and PRL. OPs and mfERG N1 amplitudes were significantly reduced in the nasal hemiretina of patients. Significant correlations were found between OP and mfERG amplitudes for inner and outer nasal hemiretina OCT measurements, respectively. Conclusions: Patients with permanent temporal hemianopia from previously treated chiasmal compression displayed significant RNFL, GCL, IPL thinning and INL, OPL and PRL thickening associated with reduced OP and mfERG N1 amplitudes, suggesting axonal injury to the inner retina leads to secondary damage to the outer retina in this condition

The main target of this work is a design of the program for border localization of the optic disc in OCT data. Part of this program is also localization of the „optic cup“ and calculation of several values that characterize optic disc. The work is also dealing with a description of the optical coherence tomography principle which is used in ophthalmology. One chapter describes some published methods of optic cup localization. Success of the program and its comparison with OCT Zeiss Stratus 3000 is evaluated at the end of the work.

This work is focused on automatic detection of optic disc in retinal images. There is briefly described anatomy of human eye, principles of retinal imaging and also overview of the methods used for optic disc detection. The practical part describes developed procedures for optic disc detection, ie detection based on watershed transform, active contours and also on region growing technique. The main method of this work is the method of circular transformation, which as the only one allowed to detect the optic disc on the images of video ophtalmoscope and also on the high quality images from fundus cameras. This method was tested on three datasets. The average overlap 92,44 % was achieved for HRF dataset, 91,03 for DRIONS dataset and 77,36 for images of video ophtalmoscope.

INTRODUCTION:Whirligig beetles (Coleoptera: Gyrinidae) are aquatic insects living on the water surface. They are equipped with four compound eyes, an upper pair viewing above the water surface and a lower submerged pair viewing beneath the water surface, but little is known about how their visual brain centers (optic lobes) are organized to serve such unusual eyes. We show here, for the first time, the peculiar optic lobe organization of the larval and adult whirligig beetle Dineutus sublineatus.RESULTS:The divided compound eyes of adult whirligig beetles supply optic lobes that are split into two halves, an upper half and lower half, comprising an upper and lower lamina, an upper and lower medulla and a bilobed partially split lobula. However, the lobula plate, a neuropil that in flies is known to be involved in mediating stabilized flight, exists only in conjunction with the lower lobe of the lobula. We show that, as in another group of predatory beetle larvae, in the whirligig beetle the aquatic larva precociously develops a lobula plate equipped with wide-field neurons. It is supplied by three larval laminas serving the three dorsal larval stemmata, which are adjacent to the developing upper compound eye.CONCLUSIONS:In adult whirligig beetles, dual optic neuropils serve the upper aerial eyes and the lower subaquatic eyes. The exception is the lobula plate. A lobula plate develops precociously in the larva where it is supplied by inputs from three larval stemmata that have a frontal-upper field of view, in which contrasting objects such as prey items trigger a body lunge and mandibular grasp. This precocious lobula plate is lost during pupal metamorphosis, whereas another lobula plate develops normally during metamorphosis and in the adult is associated with the lower eye. The different roles of the upper and lower lobula plates in supporting, respectively, larval predation and adult optokinetic balance are discussed. Precocious development of the upper lobula plate represents convergent evolution of an ambush hunting lifestyle, as exemplified by the terrestrial larvae of tiger beetles (Cicindelinae), in which activation of neurons in their precocious lobula plates, each serving two large larval stemmata, releases reflex body extension and mandibular grasp.

PURPOSE:To assess if intensity-modulated radiotherapy (IMRT) can possibly lead to improved local control and lower incidence of vision impairment/blindness in comparison to non-IMRT techniques when treating sinonasal malignancies / what is the most optimal dose constraints for the optic pathway / and the impact of different IMRT strategies on optic pathway sparing in this setting.METHODS AND MATERIALS:A literature search in the PubMed databases was conducted in July, 2012.RESULTS:Clinical studies on IMRT and 2D/3D (2 dimensional/3 dimensional) RT for sinonasal malignancies suggest improved local control and lower incidence of severe vision impairment with IMRT in comparison to non-IMRT techniques. As observed in the non-IMRT studies, blindness due to disease progression may occur despite a lack of severe toxicity possibly due to the difficulty of controlling locally very advanced disease with a dose less than or equal to] 70Gy. Concurrent chemotherapy's influence on the the risk of severe optic toxicity after radiotherapy is unclear. A maximum dose of less than or equal to] 54Gy with conventional fractionation to the optic pathway may decrease the risk of blindness. Increased magnitude of intensity modulation through increasing the number of segments, beams, and using a combination of coplanar and non-coplanar arrangements may help increase dose conformality and optic pathway sparing when IMRT is used.CONCLUSION:IMRT optimized with appropriate strategies may be the treatment of choice for the most optimal local control and optic pathway sparing when treating sinonasal malignancy.

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / In this paper, we investigate high-capacity fiber-optic networks for real-time telemetry applications. The network topologies and related network components are analyzed for telemetry fiber-optic Local Area Network (LAN) and Metropolitan Area Network (MAN) as well as MAN internetworking with LANs. Two types of multiplexing techniques, namely, Wavelength Division Multiplexing and Time Division Multiplexing, are proposed to support real-time high-capacity telemetry applications, and the perspective of such networks is also considered. Finally, the optical modulation technique and the choice of optical devices are discussed, which are based on improving the reliability of fiber-optic LANs and MANs.

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

In this paper, we present the results of the design and fabrication of a 12 channel nano-membrane-based optical phased array that allows for large angle beam steering operating at wavelength=1.55µm. Our device is fabricated on silicon-on-insulator using standard CMOS process. By implementing unequally spaced waveguide array elements, we can relax the half-wavelength spacing requirement for large angle beam steering, thereby avoiding the optical coupling between adjacent waveguides and reducing the side-lobe-level of the array radiation pattern. 1D beam steering of tranverse-electric polarized single mode light is designed to be achieved thermo-optically through the use of thin film metal phase shifters. / text