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At least 793 records · Page 44Linked to original sources
PubMed1995

Prevalence of primary acquired melanosis and nevi of the conjunctiva and uvea in the dysplastic nevus syndrome. A case-control study.

PURPOSE: To investigate whether conjunctival and uveal nevi and primary acquired melanosis are more common in individuals with the dysplastic nevus syndrome than in control subjects derived from the general population. METHODS: Power calculations were used to determine the sample size. After invitation, 162 individuals with the dysplastic nevus syndrome and 119 control subjects, matched for sex and age but otherwise randomized from the Stockholm county census file, were entered into the study. All individuals were examined in a masked fashion by the same ophthalmologist, and the presence of conjunctival and uveal melanocytic lesions and the iris color, skin type, and hair color of each individual were recorded. Contingency tables and odds ratios were used for statistical evaluation. RESULTS: The proportions of individuals with the dysplastic nevus syndrome featuring primary acquired melanosis of the conjunctiva, or nevi of the iris and choroid were not significantly different from those of control subjects. However, individuals with the dysplastic nevus syndrome appeared to have a more sun-sensitive skin type and a reddish or blond hair color more often than control subjects. CONCLUSION: In contrast to previous reports, this study suggests that ocular melanocytic lesions are no more common in individuals with the dysplastic nevus syndrome than in the general population. Therefore, this work does not provide support that periodic ophthalmic surveillance of individuals with the dysplastic nevus syndrome for the purpose of detecting conjunctival or uveal melanomas, or their precursors, is meaningful.

Adult↗
PubMed1997

Assessing children's ultraviolet radiation exposure: the use of parental recall via telephone interviews.

OBJECTIVES: This study evaluated the validity of a parental report measure of children's solar protection behaviors. METHODS: Fifty-eight children had skin color assessed twice with a colorimeter. Between measurement sessions, parents were interviewed by telephone to assess children's indoor-outdoor status and solar protection across 40 hourly intervals. RESULTS: Parental report of child's indoor-outdoor status was significantly correlated with the colorimeter values, whereas the use of sunscreen and protective clothing was not. CONCLUSIONS: This measure was feasible for assessing ultraviolet exposure in young children. The component that assessed the number of intervals spent outdoors evidenced predictive validity.

Child↗
PubMed2005

[Genotypic and phenotypic markers in patients with chronic obstructive bronchitis].

The study included examination of 120 patients with chronic obstructive bronchitis (COB) and 70 healthy people. The following genotypic and phenotypic markers were evaluated: blood group, Rhesus factor, earwax type, constitution, height, iris color, hair color, signs of functional asymmetry and some minimal signs of embryogenesis disturbances. The relative risk of the disease development was counted for each parameter. The study found the highest COB morbidity in short normosthenics people with short neck, wet earwax type, nasal septum deviation and B (III) blood group. Such markers as light brown hair and dry earwax type were shown to be associated with COB-protective activity. The signs discussed in the article may be used to determine predisposition to COB.

Adolescent↗
PubMed2000

Iris color and age-related changes in lens optical density.

PURPOSE: Epidemiologic evidence indicates that dark iris color increases risk of age-related cataract. No information is currently available, however, on the effects of iris color on the lens prior to cataract development. In this study, we relate iris color to lens optical density (OD) in individuals without frank cataract. METHODS: 90 subjects with blue or green irises (light color) were compared with 87 subjects having hazel, brown, or black irises (dark color). Lens OD was measured psychophysically by comparing scotopic thresholds obtained at 410 (measuring) and 550 nm (reference). Stimuli were presented in Maxwellian view. RESULTS: The groups with light and with dark iris color did not differ significantly in smoking habits, dietary patterns, or age. Despite other similarities between the groups, lens OD was significantly (p < 0.024) higher in the group with dark irises. The higher OD of the dark iris group was due to differences in the older subjects (> 45 years, p < 0.005), rather than the younger subjects (20-45 years) who showed no differences in lens OD. CONCLUSION: Our data indicate that iris pigmentation may be directly related to age-associated increases in lens OD.

Adult↗
PubMedDate not supplied

Characteristics of the iris in 100 neonates.

To better characterize the appearance of the iris at birth, we studied certain iris features of 100 normal newborns with slit lamp biomicroscopy. We noted the iris color, crypt-structure, and vascularity of the collarette and periphery of the iris. These features were considered in light of the child's birthweight, postnatal days of age, sex, and race. Iris vascularity correlated significantly with postnatal age at examination, and stage of crypt development was more advanced in males, and more evident in the blue and gray irides. Males also had a more advanced stage of iris development. In addition to our previous finding that iris vessels of cocaine intoxicated neonates were more tortuous and dilated than a control group, this study suggests that such vessels may also be more commonly found in sickly infants.

Aging↗
PubMed1977

[To some aspects of iris morphology in vertebrates (author's transl)].

The multiplicity of colorations and patterns in the irides as well as the pupillary polymorphism in vertebrates are impressing. They show the iris as an ocular part especially inclined to evolutional modifications. Species from different classes of vertebrates not uncommonly show very similar characteristics of iris morphology provided their mode of life is comparable with regard to relevant factors. On the other hand there exist many examples of very differing iris characteristics in spite of seemingly well corresponding habits of life. These cases often enough pose problems concerning the biological value of a specific variant form. They point however to a multifactorial conditioning of these phenotypic characteristics indicating simultaneously possibilities to create identical effectivities by differing means.

Amphibians↗
PubMed2002

[Variables related to the first presbyopia correction].

PURPOSE: We carried out a prospective study based on variables related to the age of appearance of presbyopia (AAP): refraction defect, sex, iris color, profession and pupil diameter. METHOD: Our sample population was made up of 179 persons who present consecutively for the first optical correction of presbyopia as sole reason, having a refractive defect equal to 1 diopter or less. RESULTS: In our series the AAP was not influenced by the small refraction defect, neither by sex or iris color. Different professions showed a significant AAP difference later in life (farmers, x = 51.76 D.E. 5.47 years) or earlier (services workers, x = 46.15 D.E. 3.55 years) (p<0.000003, ANOVA), than other professions such as housewife (48.42 D.E. 4.71 years) and construction workers (47.54 D.E. 3.93 years). We found significant differences in AAP among subjects with intense miosis (<2,5 mm, x = 51 D.E. 5.39 years) and without miosis (3 to 7 mm, x = 47.47 D.E. 4.71 years) (p<0.02 t Student). CONCLUSIONS: The variables which determine a significant delay in the AAP are: profession (farmer and housewife) and miosis, a 1 mm pupilar diameter reduction, in near vision, could contribute to a delay of 1.53 years in AAP.

Adult↗
PubMed1993

Theoretical effect of refractive error and accommodation on longitudinal chromatic aberration of the human eye.

Simple formulas based on reduced eyes have been developed to predict the variation in longitudinal chromatic aberration with variation in ametropia or accommodation. Two formulas were developed, one for axial ametropia and one for refractive ametropia. The latter also served as a model for accommodation. The results using the formulas are in close agreement with results obtained using raytracing through more sophisticated models. Combining the results of different methods gives the following predictions of change in chromatic difference of focus, between wavelengths of 400 and 700 nm, with change in each diopter of refractive error or accommodation: axial ametropia 0.012 to 0.017 D (0.6 to 0.9%), refractive ametropia 0.05 D (2.2 to 2.4%), and accommodation 0.04 to 0.05 D (2.1 to 2.6%). The chromatic aberration effects of correcting lenses with low dispersion are intermediate in effect and opposite in sign to the effects of corresponding degrees of axial ametropia and refractive ametropia.

Accommodation, Ocular↗
PubMed1999

Iris color as a prognostic factor in ocular melanoma.

BACKGROUND: Ocular melanoma may be more prevalent among patients with light irises than those with dark irises. OBJECTIVE: To examine a large clinical series of patients with intraocular melanoma to determine if light irises are associated with increased risk of death from these tumors. METHODS: A total of 1162 patients treated with proton irradiation between 1984 and 1996 were observed through 1997. RESULTS: Iris color in the patients was blue or gray in 48%, green or hazel in 30%, and brown in 23%. Tumors in patients with blue or gray irises were less heavily pigmented (P<.001) and closer to the optic disc and macula (P<.001). Five- and 10-year metastasis-related death rates were 0.14 and 0.21, respectively, for those with blue or gray irises and 0.10 and 0.15, respectively, for those with darker irises (P = .02). In a Cox proportional hazards regression controlling for tumor characteristics, patients with blue or gray irises died of metastatic disease at a rate 1.90 times (95% confidence interval, 1.26-2.85) that of patients with brown irises. The rate of metastatic death was not significantly elevated for those with green or hazel irises (relative risk, 1.43; 95% confidence interval, 0.91-2.23). CONCLUSION: Patients with blue or gray irises appear to be at increased risk of metastatic death from choroidal melanoma, independent of other risk factors.

Boston↗
PubMed2003

Determinants of skin sensitivity to solar irradiation.

BACKGROUND: Acute effects of UV irradiation include UV-induced erythema. Sunlight plays an important role in the development of skin cancer. Several predictive factors of UV-induced erythema could also be predictive for skin cancer. OBJECTIVE: Our objective was to quantitatively assess phenotypical and nutritional determinants of sensitivity to UV irradiation, as assessed by the minimal erythema dose (MED). DESIGN: We conducted a cross-sectional study among 335 volunteers. Sensitivity to UV irradiation was established through assessment of the MED. Phenotypical determinants, including skin melanin content, hair color and iris color were determined by skin reflectance spectrometry, a subjective questionnaire and an objective classification system, respectively. Furthermore, dietary exposure was measured by carotenoids, vitamin C, retinol and alpha-tocopherol in serum. RESULTS: Male subjects were found to be more sensitive to UV irradiation; that is, the MED was significantly lower compared to female subjects. Skin melanin content, which was positively associated with iris color in both sexes and with hair color in men, was the main phenotypical determinant of sensitivity to UV irradiation. No associations were found between serum carotenoids and MED in the total study group. Vitamin C was inversely associated with MED. However, associations between carotenoids concentrations and MED showed a positive trend in subjects with melanin values above and a negative trend in subjects below the median after adjustment for gender and total cholesterol. CONCLUSIONS: Skin melanin content and gender are important determinants of sensitivity to UV irradiation. No relation was found between serum carotenoids and MED in the total study group. The inverse association between vitamin C and MED was against our hypothesis. For the modifying effect of melanin on the association between carotenoids and MED, we do not have a clear biological explanation.

Adolescent↗
PubMed1990

[The complex study of the iris in transformed light].

Complex investigations of the iris in a transformed light by methods of iridochromoscopy, iridochromophotography, examination in a polarized light, transillumination in red light and fluorescence angiography was conducted in 25 eyes of patients with open-angle glaucoma, 10 eyes of patients with anterior flaccid uveitis and in 23 healthy eyes (a control group). It was found that in patients with open-angle glaucoma and anterior flaccid uveitis trophic and vascular changes in the iris predominated, as compared with control. The most typical for open-angle glaucoma changes in the iris were atrophy of the stroma with predominant involvement of the pupillary zone, exogenic pigmentation of the pupillary and ciliary zones, destruction of the pigment margin of the pupil, thickening of the anterior border layer, pseudoexfoliation of the pupillary margin, defects in the posterior pigment layer, being more extensive in the pupillary zone, as well as disturbances in permeability of the iris in a combination with hypoperfusion and rare bundles of microneovascularization in the area of a lesser arterial circle and the ciliary zone. In case of flaccid uveitis, the most frequent changes were diffuse atrophy of the iris, efflorescence of the pupillary margin, destruction of the pigment rim of the pupil, multiple defects in the posterior pigment layer along its whole length, increased permeability of vessel, microneovascularization of the iris stroma in a form of a thin vascular network.

Adult↗
PubMed2000

Close genetic similarity between two sympatric species of tephritid fruit fly reproductively isolated by mating time.

Two sibling species of tephritid fruit fly, Bactrocera tryoni and B. neohumeralis, occur sympatrically throughout the range of B. neohumeralis in Australia. Isolation between the two species appears to be maintained by a difference in mating time: B. tryoni mates at dusk, whereas B. neohumeralis mates during the middle of the day. A morphological difference in humeral callus color also distinguishes the two species. Despite clear phenotypic evidence that B. tryoni and B. neohumeralis are distinct species, genetic differentiation as measured by four markers--nuclear DNA sequences from the white gene and the ribosomal internal transcribed spacer (ITS2), and mitochondrial DNA sequences from the cytochrome b (cytb) and cytochrome oxidase subunit II (COII) genes--is very small. Minor fixed differences occur in the ITS2 sequence, however, in all other cases the two species exhibit a high level of shared polymorphic variation. The close genetic similarity suggests either that speciation has occurred very rapidly and recently in the absence of any mitochondrial DNA sorting or that the sharing of polymorphisms is due to hybridization or introgression. A third species within the tryoni complex, B. aquilonis, is geographically isolated. Bactrocera aquilonis is also genetically very similar, but in this case there is clear differentiation for the mitochondrial loci. The three species form a group of considerable interest for investigation of speciation mechanisms.

Amino Acid Sequence↗
PubMed2001

Contrast-enhanced ultrasound Doppler examination of the retrobulbar arteries.

PURPOSE: To evaluate the diagnostic usefulness of an ultrasound contrast agent in examination of the retrobulbar arteries. MATERIAL AND METHODS: Ten healthy volunteers received a galactose-based echo-contrast medium (Levovist) by i.v. infusion. The ophthalmic, central retinal, the nasal and the temporal posterior ciliary arteries and the short ciliary arteries were studied in 19 eyes by color and spectral Doppler ultrasonography before and after contrast administration. Peak systolic and end diastolic velocities and spectral Doppler indices (pulsatility and resistive) were assessed. The quality of the spectral and color Doppler imaging of the arteries were visually graded on a 5-point scale. RESULTS: There were significant differences in pre- and post-contrast peak systolic velocities in the ophthalmic arteries (p<0.05), but not in the other retrobulbar arteries, or in any of the spectral Doppler indices. After contrast administration the mean spectral Doppler score for vessels poorly visualized before contrast increased from 2.2 (+/-0.4) to 3.1 (+/-0.9). The number of short ciliary arteries with sufficient spectral Doppler quality increased from 7 prior to contrast to 14 following contrast. Prior to the infusion of Levovist, 62 (73%) out of 85 retrobulbar arteries could be evaluated with a sufficient spectral Doppler quality. Following the administration of contrast 66 (78%) arteries had sufficient spectral Doppler quality. However, by combining the results of the pre- and post-contrast examinations, sufficient spectral Doppler quality was obtained in 77 (91%) of the 85 retrobulbar arteries. CONCLUSION: Contrast enhancement increased the number of detectable retrobulbar vessels. However, in the case of good quality pre-contrast imaging of the retrobulbar vessels, the use of Levovist did not add any substantial diagnostic information. The optimal spectral Doppler results were obtained when both pre- and post-contrast examinations were performed.

Adult↗
PubMedDate not supplied

Prevalence of unilateral and bilateral deafness in border collies and association with phenotype.

BACKGROUND: Congenital sensorineural deafness (CSD) occurs in Border Collies, but its prevalence and inheritance are unknown. This study estimated the prevalence of CSD in Border Collies and investigated its association with phenotypic attributes linked to the merle gene, including coat pigmentation and iris color. HYPOTHESIS: Deafness in Border Collies is associated with pigmentation patterns linked to the merle gene. ANIMALS: A total of 2597 Border Collies from the United Kingdom. METHODS: A retrospective study of Border Collies tested, during 1994-2002, by using brainstem auditory evoked responses. Associations between deafness and phenotypic attributes were assessed by using generalized logistic regression. RESULTS: The prevalence of CSD in puppies was estimated as 2.8%. The corresponding rates of unilateral and bilateral CSD were 2.3 and 0.5%, respectively. Adjustment for clustering of hearing status by litter reduced the overall prevalence estimate to 1.6%. There was no association between CSD and sex (P = .2). Deaf Border Collies had higher rates of merle coat pigmentation, blue iris pigment, and excess white on the head than normal hearing Border Collies (all P < .001). The odds of deafness were increased by a factor of 14 for Border Collies with deaf dams, relative to the odds for dogs with normal dams (P = .007), after adjustment for phenotypic attributes. CONCLUSIONS AND CLINICAL IMPORTANCE: Associations between CSD and pigmentation patterns linked to the merle gene were demonstrated for Border Collies. Evidence for an inherited component to CSD in Border Collies supports selective breeding from only tested and normal parents to reduce the prevalence of this disease.

Age Factors↗
PubMed1992

[The color and structure of the human iris. 2. Studies of 200 twins].

Subject of the present report is an investigation of the heredity of 30 iris characteristics. The material basis of this sample of twins (100 monozygotic and 100 dizygotic pairs), the largest ever taken as a basis for the purpose of iris research, consists of standardized colour photographs of the examined persons' irises and iris-microscopic observations. The pairs of twins are compared to 100 non-related casual pairs in order to render a better estimation of the degree of heredity of the features possible. On every occasion several classes were constituted for the concordance verification. These classes result from the number of the classes of the forms of markedness and present different levels of similarity. The different distribution of the twin pairs and the control pairs on the concordance classes are always examined for their statistical significance, and for each group of pairs a concordance value is computed. The intervals between the concordance values of the monozygotic and dizygotic pairs and the control pairs indicate the degree of heredity of the investigated feature. Taking all the compiled factors and conditions into consideration, an evaluation of the features as heredity features is made. Though a hereditary component can be observed for all iris characteristics, only about a third could be called heredity features. Quantity of pigment and the hitherto undescribed limiting layer folds were evaluated as "very good", whereas pigment colour in the fine analysis, quality of the anterior stroma leaf, frequency of iris crypts and iris frill position were judged as "good". Tone of blue, markedness of Woelfflin nodules, quantity and markedness of contractional rings could be evaluated as "moderately good" as to their heredity. On the basis of the prior concordance investigations for each of the 300 pairs, a "similarity index" and a "concordance index" were computed in order to arrive at evidence as to the degree of similarity of the single pairs; i.e. in order to detect the limits of the similarity between non-identical twins and the dissimilarity between identical twins. This concluding investigations lead to the question of the possibility of a diagnosis of genetic identicalness solely on the basis of the comparison of irises.

Adolescent↗
PubMed2001

Clinical investigation of a true color scanning laser ophthalmoscope.

OBJECTIVE: To show true color scanning laser ophthalmoscope (SLO) images produced by simultaneously imaging the retina with red, green, and blue lasers. METHODS: Low-power red, green, and blue lasers were combined using fiber optics. By rapidly pulsing the lasers, each point on the fundus is illuminated by the 3 colors in quick succession, with the total power level being similar to that from a single laser. The reflected light is then decoded to extract the red, green, and blue color information and the true color fundus image is displayed live on a computer monitor. RESULTS: Comparison was made between the color SLO images from 5 patients and their digitized fundus photographs. The background fundus and retinal vasculature showed a similar appearance. The SLO gave better quality information in patients with ocular histoplasmosis, macular dystrophy, and optic disc drusen. By operating the color SLO in the indirect mode, macular edema could be clearly seen as lines and ridges surrounding the fovea. CONCLUSION: The color SLO offers all the advantages of the present commercially available monochromatic device, with the added advantage of true color representation of the fundus without increasing either imaging time or the level of exposure.

Adult↗