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At least 595 records · Page 33Linked to original sources

Color Doppler imaging of the eye and orbit. Technique and normal vascular anatomy.

Color Doppler imaging is a recent advance in ultrasonography that allows simultaneous two-dimensional imaging of structure and blood flow to be performed. Doppler information is superimposed in color over a conventional gray-scale ultrasound image. Using this technique, we examined 40 normal eyes. The central retinal artery, posterior ciliary arteries, ophthalmic artery, and central retinal vein could be located in all patients. Using the color image as a guide, Doppler spectral analysis allows quantitative assessment of blood flow velocity in these vessels. Color Doppler imaging is a new modality for the study of ocular and orbital hemodynamics.

Adult↗

Assessment of potential macular function using a color saturation discrimination test in eyes with cataract.

PURPOSE: To study the efficacy of a color saturation discrimination test (CSDT) in assessing potential macular function in eyes with cataract. SETTING: Yamanashi Medical University and Nirasaki City Hospital, Yamanashi, Japan. METHODS: In this prospective study of 200 consecutive eyes with cataract, the thresholds of color saturation discrimination on 6 hues were measured with the CSDT. The CSDT program was run on a personal computer and cathode-ray tube color monitor. The preoperative CSDT scores and postoperative visual acuities were compared. In addition, preoperative laser interferometry (LI) and postoperative CSDT were performed on selected patients and the results compared with their preoperative CSDT results. RESULTS: Patients who had a CSDT score of 11 or more had a significantly lower postoperative visual acuity (P < .0001). The prevalence of neuroretinal abnormality postoperatively increased with the preoperative CSDT score. The CSDT score was not correlated with preoperative visual acuity (P = 1409). Cataract severity had little influence on the CSDT score. The preoperative results of the CSDT and Ll were correlated with the postoperative acuity, with the correlation coefficient being stronger with the CSDT (r = -0.338 and 0.276 for CSDT and Ll, respectively). CONCLUSION: The CSDT was effective in evaluating neuroretinal pathology and predicting postoperative acuity.

Cataract↗

Melanin in human irides of different color and age of donors.

Melanin is the main chromophore of the human iris. This pigment is considered to be the most important factor that determines the color of the irides. Previous studies based mainly on chemical degradation methods showed that brown irides contain more melanin than blue ones. In our study, we used electron spin resonance (ESR) spectroscopy to detect and characterize melanin free radical centers and associated iron in human irides. Based on this method, we determined the amount of melanin in the irides and the relative content of iron in iridial melanin as a function of their color, shade, and the age of their donors. Chemical degradation of iridial homogenates enabled us to characterize the structure of eumelanin and determine the content of pheomelanin present in human and bovine irides. The ESR amplitude, the normalized intensity obtained by double integration of the ESR signal of melanin, and the content of the pigment in the irides depended on color and shade of the eyes being 40% higher in the brown group of the irides compared with all other groups. On the other hand, the relative iron content normalized to the melanin content in light blue irides showed a small decrease with age of donors. Melanin in human and bovine irides was mostly composed of eumelanin, and pheomelanin content was of the order of a few percent. Although some differences in the structure of eumelanin present in the human and bovine irides are possible, the results obtained in this study suggest that human irides contain eumelanin with very similar chemical properties.

Adolescent↗

Iris-color change developed after topical isopropyl unoprostone treatment.

PURPOSE: To present a case in which iris pigmentation developed after treatment with isopropyl unoprostone, an analogue of a prostaglandin metabolite. METHODS: Case report. RESULTS: A Japanese man with dark brown irises, treated unilaterally with isopropyl unoprostone, developed iris-color change in the treated eye after a 20-month treatment. CONCLUSIONS: Isopropyl unoprostone can induce iris pigmentation as does latanoprost.

Administration, Topical↗

[Evaluation of circulatory flow in vessels of the eye and orbit using color duplex ultrasonography].

Duplex ultrasonography is recent imaging, that allows simultaneous 2-dimensional imaging (B-scan) and Doppler evaluation of the blood flow. Information on blood flow is obtained by pulsed Doppler spectral analysis. The blood flow in vessels of our interest is colour coded. Using this technique we examined 140 eyes. 81 eyes in 48 healthy persons were examined. Based on this examinations, the blood velocity standards were calculated for age groups 19-40 and 41-76 y. There are demonstrated pathologic findings by intraocular tumor, tractional retinal detachment and various failures of blood flow in bulbar and orbital vessels.

Adult↗

Rayleigh matches and unique green.

There are recurrent reports that Rayleigh matches are bimodally distributed in the colour-normal male population. Similar claims have been made for the distribution of the spectral locus of unique green. Moreover, a positive correlation has sometimes been reported between Rayleigh matches and unique green. Using a computer-controlled Maxwellian colorimeter and bias-free psychophysical methods, we measured both variables for 97 colour-normal male observers. We do not find a bimodal distribution either of Rayleight matches or of settings of unique green. Nor do we find any correlation between the two variables. However, we do observe a very significant relationship between the lightness of the subject's iris and the wavelength that he judges to be unique green.

Adaptation, Ocular↗

Three-dimensional modeling of the human eye based on magnetic resonance imaging.

PURPOSE: A methodology for noninvasively characterizing the three-dimensional (3-D) shape of the complete human eye is not currently available for research into ocular diseases that have a structural substrate, such as myopia. A novel application of a magnetic resonance imaging (MRI) acquisition and analysis technique is presented that, for the first time, allows the 3-D shape of the eye to be investigated fully. METHODS: The technique involves the acquisition of a T2-weighted MRI, which is optimized to reveal the fluid-filled chambers of the eye. Automatic segmentation and meshing algorithms generate a 3-D surface model, which can be shaded with morphologic parameters such as distance from the posterior corneal pole and deviation from sphericity. Full details of the method are illustrated with data from 14 eyes of seven individuals. The spatial accuracy of the calculated models is demonstrated by comparing the MRI-derived axial lengths with values measured in the same eyes using interferometry. RESULTS: The color-coded eye models showed substantial variation in the absolute size of the 14 eyes. Variations in the sphericity of the eyes were also evident, with some appearing approximately spherical whereas others were clearly oblate and one was slightly prolate. Nasal-temporal asymmetries were noted in some subjects. CONCLUSIONS: The MRI acquisition and analysis technique allows a novel way of examining 3-D ocular shape. The ability to stratify and analyze eye shape, ocular volume, and sphericity will further extend the understanding of which specific biometric parameters predispose emmetropic children subsequently to develop myopia.

Adult↗

[Color sensation of pseudophakic eye from a viewpoint of electrophysiological study].

Monochromatic ERG b-waves were recorded in normal eyes, cataractous eyes and pseudophakic eyes implanted with non-UV or UV IOLs. ERG b-waves were elicited by fourteen monochromatic stimulus lights ranging from 400 to 660 nm under white light adaptation, and spectral response curves were obtained from b-wave amplitudes. Compared with normal eyes or cataractous eyes, the relative b-wave amplitude of pseudophakic eyes was significantly larger in the short wavelength range from blue to green. Except for 400 nm, the spectral response curve of the eyes implanted with UV IOLs was similar to that of eyes implanted with non-UV IOLs. These results suggested that dyschromatopsia might not only occur in eyes implanted with non-UV IOLs but in eyes with UV IOLs.

Aged↗

[Color differences between light-cured composite resin made shade guides and manufactured shade guides].

The purpose of this study was to investigate color differences between shade guides and light-cured composite resins. Resin specimens were made with resins and opaque resins of Silux Plus and Silux (3 M Co.) in a shade-guide metal mold. The resin specimens and the shade guides therefore were identical in shape and size. The sample resin specimens were compared with the shade guides provided with Silux Plus and Silux light-cured composite resins. Color measuring was performed with the Murakami Color Research Laboratory Fast Spectrophotometer C M S -500 and the Flexible Sensor F S -1. Specimens were placed on a plastic disc fixed to the top of the flexible sensor, and identical areas of their incisal, central, and cervical parts were measured. Conclusions. 1) The delta E*ab values between all shade guides and resin specimens showed color differences detectable to the naked eye. 2) Color differences between shade guides and resin specimens were great for the incisal colors (I, X L) and the deep and dark colors (D G, D Y, Y B, D G O, D Y O, Y B O, D D Y O). Color differences were relatively small, however, for the general colors (U, Y, G, U O, Y O, G O). 3) The L* values of shade guides ranged more widely than those of resin specimens. For many colors, L* values of the shade guides were lower than those of the resin specimens. 4) The a* values of shade guides and resin specimens were much more limited. The a* values of all colors showed minus values. The magnitude of a* values of shade guides were lower than those of resin specimens. 5) The b* values of shade guides were higher for some colors and lower for some colors than those of resin specimens.

Bisphenol A-Glycidyl Methacrylate↗