For inspection purposes first ideas of an in-pipe robot are presented. The idea of a rover with respect to the environmental conditions, as well as details of structure, actuation, measurement and ...control concepts is discussed in this document. It should be able to navigate through rather narrow and buckled drainage pipes with diameters not much larger than the robot itself, so the design is aiming for a most compact and potentially self-disassembling solution necessary for cases of stuck robots.
A compact, low-cost, prismless Ti:Al2O3 laser with 176-nm bandwidth (FWHM) and 20-mW output power was developed. Ultrahigh-resolution ophthalmic optical coherence tomography (OCT) ex vivo imaging in ...an animal model with approximately 1.2-microm axial resolution and in vivo imaging in patients with macular pathologies with approximately 3-microm axial resolution were demonstrated. Owing to the pump laser, this light source significantly reduces the cost of broadband OCT systems. Furthermore, the source has great potential for clinical application of spectroscopic and ultrahigh-resolution OCT because of its small footprint (500 mm x 180 mm including the pump laser), user friendliness, stability, and reproducibility.
To compare the magnification properties of four different indirect double aspheric fundus examination lenses for clinical disc biometry.
Experimental study in a model eye. The relationship between ...the true size of a fundus object and its image was calculated for each fundus lens for an ametropic range between -12.5 and +12.6 D using a slit lamp biomicroscope with adjustable beam length.
Equations for determining the correction factor p (degrees per millimeter) were calculated for each fundus lens. The factor can be used in calculations to determine true optic disc size. The total change in magnification of the system from myopia to hyperopia was -21.1% to +24.0% (60-D lens; Volk Opticals, Mentor, OH), -12.9% to +16.2% (Volk super 66 stereo fundus lens), -13.2% to +13.9% (Volk 78-D lens), and -13.3% to +14.0% (Volk super-field NC lens). When the fundus lens position was altered im relation to the model eye by +/-2 mm under myopic conditions, the change in magnification of the system was -4.3% to +5.7% (60-D lens), -4.6% to +6.1% (66 stereo fundus lens), -4.9% to +6.3% (78-D lens), and -5.9% to +7.8% (super-field NC lens). In the hyperopic condition the change was -2.7% to +3.6%, -3.4% to +4.5%, -3.6% to +4.8%, and -4.5% to +6.0%.
The study has shown that the use of a single magnification correction value for each fundus lens may not be appropriate. These findings have important implications for the way in which calculations for determining the true optic disc size and other structures of the posterior pole are performed using indirect biomicroscopy.
Age-related macular degeneration (AMD) is a chronic, progressive, degenerative disease of the macula and is the leading cause of central vision loss among elderly people in the western world. ...Traditionally, clinical studies of AMD have described the impact of AMD, and treatments for AMD, in terms of the patient's visual acuity. However, visual acuity alone does not provide information about a patient's perception of his or her quality of life. Researchers have used a variety of instruments to measure quality of life. Several studies have shown that AMD can severely impair quality of life and that increasing vision loss is associated with increasing impairment of quality of life and frequently causes depression. Interestingly, patients with only one eye affected may become more depressed than those with both eyes affected, possibly because of uncertainty surrounding future vision loss in patients with one eye affected and a greater acceptance of the condition in those with both eyes affected. Studies also have provided some information on the possible quality of life benefits of therapy for AMD. By incorporating measurements of quality of life into the design of future prospective studies, clinical researchers may be able to obtain more comprehensive data on the impact of AMD on patients and the relative benefits of different therapies.
To determine whether differences in baseline lesion size and visual acuity might explain differing results found in three different lesion compositions (predominantly classic, minimally classic, and ...occult with no classic) among three placebo-controlled, randomized clinical trials evaluating photodynamic therapy with verteporfin (Visudyne, Novartis AG), also termed verteporfin therapy, in patients with subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD).
Exploratory analyses were conducted in patients with predominantly classic or minimally classic lesions at enrollment in the Treatment of AMD with Photodynamic Therapy (TAP) Investigation and in AMD patients with occult with no classic CNV in the Verteporfin In Photodynamic Therapy (VIP) Trial. Baseline characteristics of patients among these three lesion compositions were compared. In addition, multiple linear regression modeling was used to explore the effect of baseline lesion size, visual acuity, and lesion composition on mean change in visual acuity from baseline to 24 months.
At baseline, the mean size of predominantly classic lesions (3.4 disk areas) was smaller than that of minimally classic (4.7 disk areas) and occult with no classic lesions (4.3 disk areas). In the multiple linear regression model of individual lesion compositions, there was a significant treatment-by-lesion-size interaction for minimally classic and occult with no classic lesions, but not for predominantly classic lesions. Interaction between treatment and baseline visual acuity was not significant for any lesion composition. Small verteporfin-treated lesions lost less vision than large verteporfin-treated lesions in each lesion composition. In the multiple linear regression model that included all lesion compositions, lesion size was a more significant predictive factor for the magnitude of treatment benefit than either lesion composition or visual acuity. Smaller (4.0 disk areas or less) minimally classic and occult with no classic lesions had similar visual acuity outcomes to those observed in predominantly classic lesions.
Based on exploratory analyses, lesion size in the TAP Investigation and VIP Trial was an important predictor of the magnitude of treatment benefit with verteporfin therapy in occult with no classic and minimally classic lesion compositions. In patients with AMD, treating smaller rather than larger neovascular lesions, regardless of lesion composition, likely will result in a better level of visual acuity.
To assess photoreceptor morphology in patients with Stargardt's disease and fundus flavimaculatus using ultrahigh-resolution optical coherence tomography (UHR-OCT) and correlate it with visual acuity ...(VA).
This was a prospective observational case series. Fourteen patients with Stargardt's disease (nine women, five men; average age, 39 years; range, 27-53) were examined. A clinically viable UHR-OCT system employing a new, compact titanium sapphire laser was used, enabling a 3-microm axial resolution in the retina. All patients received a full ophthalmic examination, including fluorescein angiography. Outcome was judged by central transverse photoreceptor loss, central foveal thickness, VA, central atrophy according to fluorescein angiography, and fundus autofluorescence.
UHR-OCT was capable of visualizing and quantifying regions of central transverse photoreceptor (PR) loss. All Stargardt patients with central atrophy had a complete loss of the central photoreceptor layer in the foveal region (mean transverse photoreceptor loss, 4390 +/- 2270 microm; range, 530-9240 microm). Patients without clinically evident central atrophy had an intact photoreceptor layer centrally, but had small, focal parafoveal defects. A correlation was detected between VA and transverse PR loss (Spearman rho=-0.60, P=0.03), which was confirmed on logistic regression analysis (R2=0.49, P=0.0001). Central foveal thickness was reduced in patients with Stargardt's disease (85 +/- 40 microm; range, 58-280 microm). The correlation was statistically significant with VA (Spearman rho=0.43, P=0.04), but not with transverse PR loss (Spearman rho=-0.23, P >>0.05). Linear regression analysis showed a statistically significant association of central foveal thickness with VA (R2=0.51, P=0.0001), but not with transverse PR loss (P >>0.05). The extent of atrophy seen in fluorescein angiography correlated with VA and transverse PR loss (Spearman rho=-0.51, P=0.007; Spearman rho=0.77, P=0.0001). Similar correlations were found with the maximum transverse diameter of fundus autofluorescence (Spearman rho=-0.72, P=0.008; Spearman rho=0.77, P=0.003).
Ultrahigh-resolution OCT demonstrates excellent visualization of intraretinal morphology and enables quantification of the photoreceptor layer. Thus, for the first time, an in vivo visualization and quantification of transverse, central photoreceptor loss and correlation with visual function is possible. Lower VA corresponds to a greater transverse photoreceptor loss, which also correlates with the extent of changes seen in fluorescein angiography and in fundus autofluorescence. Furthermore, reduced retinal thickness (i.e., atrophy of retinal layers) does not correlate with the transverse extent of PR loss. Thus, it seems that although there may be progressive atrophy of intraretinal layers, an intact photoreceptor layer leads to better VA. UHR-OCT may present a viable alternative to the assessment of central visual function, due to the easy, objective, and noninvasive data acquisition. Therefore, UHR-OCT could be of future use in judging patients' prognoses in Stargardt's disease.
This article argues that as the United States attempted to salvage its image as a benevolent nation in the wake of the Vietnam War, a movement of Vietnamese refugees demanding repatriation challenged ...the notion that the evacuation of Vietnamese was a necessary rescue operation motivated by humanitarian concern. Via wire reports and communiqués, the Vietnamese government accused the United States of fabricating a humanitarian emergency in order to continue meddling in Vietnam’s affairs. In the broader picture of U.S. foreign relations, the repatriate issue threatened to undermine America’s efforts to rehabilitate its image of itself as a benevolent power at a time when the United States had lost credibility due to misguided policy decisions, atrocities committed by American troops during the Vietnam War, and the postwar embargo. Images of Americans embracing Vietnamese refugees served as a form of damage control as the United States sought to reclaim its moral authority, which had undergirded the benevolent image it had used to justify its intervention in Vietnam in particular and global dominance in general.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
8.
TTT and CNV ERGUN, ERDEM; STUR, MICHAEL
British journal of ophthalmology,
08/2001, Letnik:
85, Številka:
8
Journal Article
Recenzirano
Odprti dostop
...Newsom et al cannot compare their visual results adequately as the TAP study used a standardised testing procedure employing Early Treatment for Diabetic Retinopathy charts as well as masked and ...certified vision examiners in comparison to the Snellen values mentioned in the above study, which were obtained by unmasked, and therefore biased, examiners.
Imaging studies suggest that the choroidal vasculature may be altered in central serous chorioretinopathy. Little is known, however, about the regulation of ocular blood flow in patients with central ...serous chorioretinopathy (CSC). The hypothesis for the present study was that choroidal blood flow changes during an increase in ocular perfusion pressure induced by isometric exercise may be altered in CSC.
An observer-masked, two-cohort study was performed in 14 nonsmoking patients with chronic-relapsing but inactive CSC and in 14 healthy nonsmoking volunteers. Both groups were matched for age and sex. Subfoveal choroidal blood flow (CBF) was assessed with laser Doppler flowmetry, and ocular perfusion pressure (OPP) was calculated from mean arterial pressure (MAP) and intraocular pressure (IOP). Changes of CBF during isometric exercise over a period of 6 minutes were measured.
Whereas the increase of MAP, the pulse rate, and the OPP were comparable between the two study groups, subfoveal CBF increased significantly more in the group of patients with CSC (P < 0.001). IOP remained unchanged in both groups during isometric exercise. At an 85% increase in OPP, subfoveal CBF was approximately twice as high in the patients with CSC compared with the healthy control group.
The data indicate an abnormal subfoveal CBF regulation in patients with relapsing CSC compared with age-matched, nonsmoking, healthy volunteers during isometric exercise.
AIM A study was undertaken to investigate the correlation between colour discrimination tests and the presence of macular oedema in patients with type I diabetes to find a sensitive diagnostic tool ...for the detection of early functional changes. METHODS The study was performed in 39 type I diabetic patients, 10 with and 29 without macular oedema. The examination included biomicroscopy, fundus photography of the macula, videofluorescein angiography, the LogMAR visual acuity chart, Farnsworth-Lanthony desaturated D-15 test, and the new Mollon-Reffin “Minimalist” test for colour vision deficiencies version 6.0. RESULTS A highly significant correlation was found between the tritan value of the Mollon test and the presence of clinically significant macular oedema (p<0.0015), with a high sensitivity (88.9%) and specificity (93.3%). The DD-15 test was not significant (p=0.345) and showed low sensitivity for the presence of macular oedema (36%). All variables concerning the grading of macular oedema showed a highly significant association with the tritan values of the Mollon test (p<0.0001). CONCLUSION The results suggest that the Mollon-Reffin “Minimalist” test version 6.0 is the best colour discrimination test for detecting macular oedema, with higher specificity and sensitivity than the other methods used in the study.
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