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At least 685 records · Page 38Linked to original sources
PubMed2002

Effects of C-nitropyrazoles and C-nitroazoles on ocular blood flow and retinal function recovery after ischemic insult.

AIM: Effects of C-nitropyrazoles and C-nitroazoles on ocular blood flow and retinal function recovery after ischemia have been studied. METHODS: The compounds were tested on ocular blood flow of ocular hypertensive (40 mmHg) rabbit eyes with colored microsphere technique. They were also tested on the retinal function recovery after ischemia of rat eyes with electroretinography. RESULTS: All compounds (DC-1 through DC-17) showed significant increase in retinal function recovery after ischemia in the range of 26 % to 120 % (P<0.05). Among five compounds (DC-1 through DC-5) studied, four compounds (DC-2 through DC-5) increased the blood flow in choroid, iris, and ciliary body, but not in retina. DC-1 did not show significant increase of blood flow in any of these ocular tissues. CONCLUSION: C-Nitropyrazoles can facilitate significant retinal function recovery after ischemic insult through the increase of ocular blood flow. Since rabbit's retina is scarce in vasculature, it did not show significant change in blood flow by C-nitropyrazoles as expected. Among all 17 compounds, DC-5 seems to be the most potent compound.

Animals↗
PubMed1983

The effects of the pink-eyed unstable gene on the retinal pigment epithelium of the mouse.

Pink-eyed unstable (pun), an autosomal gene in the mouse, causes variegation of the coat. In some melanocytes it functions as the normal allele p+, producing dark pigment, and in others as the mutant p, producing light pigment. As a study of another unstable gene at a different locus had shown that the instability was strongly influenced by the tissue environment, it seemed desirable to find out whether this also applied to pun. An examination of the retinal pigment epithelium, the only structure in mammals in which it is practicable to determine the position of individual melanocytes, showed that the distribution of dark and light cells in pun pun animals was not random. The dark cells increased in frequency with the distance from the optic nerve, suggesting that the tissue environment was a factor in the instability of the gene (i.e. in its rate of mutation), although the increase was less striking than in the other mutant. It is generally assumed that when pun behaves as p+ it is a case of reversion, and that reversion can also occur in germ cells, the revertant p+ allele subsequently behaving as a stable gene. It is here argued that it is unlikely to be a case of reversion, and that the evidence for the involvement of the germ line is inconclusive. Further, it is suggested that the phenotype of pun pun animals is probably an instance of Position Effect variegation, the instability resulting from some chromosomal alteration, which is too small to be cytologically detectable.

Alleles↗
PubMed2004

Analysis of irises with a latanoprost-induced change in iris color.

PURPOSE: To study the histologic aspects of irises subjected to extended latanoprost treatment. DESIGN: Prospective, observer-masked study. METHODS: Iris biopsies of eyes treated with latanoprost were analyzed (all had a photographically documented increase in iris pigmentation) plus control eyes (untreated with prostanoids) using optical microscopy. PATIENT OR STUDY POPULATION: There were 14 study eyes treated with latanoprost and 8 untreated control eyes. MAIN OUTCOME MEASURE: The morphologic characteristics of the irises. RESULTS: The irises treated with latanoprost had an increased number of melanocytes with nuclear inclusions, granules of melanin in the vascular walls and the melanocytes and free granules in the stroma compared with control eyes (P = .001, P = .01, P = .004, P = .01, respectively, by the chi(2) test). CONCLUSIONS: Chronic therapy with latanoprost appears to induce more changes in the iris than a simple increase in the melanin content of the melanocytes.

Aged↗
PubMed1995

Noninvasive assessment of the ocular circulation: color Doppler imaging.

BACKGROUND: Color Doppler Imaging (CDI) has become instrumental in the noninvasive study of vascular disorders. CDI provides information about presence and direction of blood flow, flow velocity and flow disturbances in real-time with anatomical localization. METHODS: The medical and ophthalmic literature was reviewed to gather information about color Doppler technology and its application in ocular disease. RESULTS: Resolution limits of conventional ultrasound have previously prevented reliable noninvasive imaging of small vessels in the eye. CDI now permits the reliable identification of small blood vessels and measurements of blood flow within the eye. CONCLUSIONS: Color Doppler technology remains prohibitively expensive and therefore is not widely available. How this technology can be used for ophthalmic application is still a relatively new area of research and more studies are needed to determine the reliability and limitations of CDI when it is used to image the eye and how it compares to other imaging techniques that are currently in use.

Blood Flow Velocity↗
PubMed1991

Peripheral color contrast. A new screening test for preglaucomatous visual loss.

A new test of peripheral color contrast is described. A high-definition color monitor driven by a personal computer with a graphics interface card displays an annulus subtending 25 degrees at the eye. The color contrast between the annulus and the background can be varied. Forty-five degrees of the annulus is randomly removed in one of four quadrants. Patients are asked to identify the position of the gap while fixating a central spot. The minimum color contrast between annulus and background at which the identification is possible is between 13-16% for the protan, deuteran, and tritan axis in normal subjects. This threshold value changes little with age, refractive error, or pupillary aperture, and test-retest variability is low. Testing one eye takes only 1-2 min. The test was applied to ocular-hypertensive and glaucomatous patients. All patients with glaucoma had thresholds greater than two standard deviations (SD) above the normal mean. In addition, 97% of glaucoma patients had thresholds greater than four SDs, and 95% had thresholds more than five SDs above the normal mean. Most patients with ocular hypertension and clinical signs indicating a low or medium risk of conversion to glaucoma had thresholds under the upper limit of normal. High-risk patients with ocular hypertension fell into two groups. One approximated to normal; the other had elevated thresholds, which in many cases were more than four SDs above the normal mean. The epidemiologic consequences of this test are discussed.

Adult↗
PubMed2001

The Age-Related Eye Disease Study system for classifying age-related macular degeneration from stereoscopic color fundus photographs: the Age-Related Eye Disease Study Report Number 6.

PURPOSE: To describe the system for grading age-related macular degeneration from fundus photographs in the Age-Related Eye Disease Study. This is a prospective multicenter cohort study of the course of age-related macular degeneration and a placebo-controlled clinical trial of the effect of high-dose vitamin and mineral supplements on development of advanced age-related macular degeneration. METHODS: Standardized stereoscopic 30-degree color fundus photographs are taken at 11 clinical centers and evaluated by graders at a reading center for quality and age-related macular degeneration abnormalities. Macular subfields are defined by a grid, and presence and severity of various age-related macular degeneration abnormalities are graded using standard/example photographs and measuring circles. Advanced age-related macular degeneration abnormalities (presence/absence) include retinal pigment epithelial detachment, serous (or hemorrhagic) sensory retinal detachment, hard exudates, subretinal/subretinal pigment epithelial hemorrhage, subretinal fibrous tissue, and photocoagulation scars. Other abnormalities (multistep scales) include retinal pigment epithelial abnormalities (geographic atrophy, depigmentation, and increased pigment), and drusen (size, type [hard versus soft distinct or indistinct], and total area). Contemporaneous variability is tested by having different graders evaluate samples of photographs, and temporal variability by annual regrading of a dedicated subset. RESULTS: In a cumulative sample of 1230 eyes for contemporaneous reproducibility, agreement on advanced age-related macular degeneration was 96% (kappa = 0.88) and for four-step age-related macular degeneration level was 83% (kappa = 0.77). Agreement was moderate for pigment epithelial detachment (kappa = 0.54) and substantial for serous sensory retinal detachment, hard exudates, subretinal/subretinal pigment epithelial hemorrhage, subretinal fibrous tissue, and central geographic atrophy (kappa = 0.73-0.82). For pigment abnormalities, agreement was substantial for geographic atrophy (kappa = 0.63; kappa(weighted) = 0.71, 0.75 weight for one-step disagreements), and moderate for depigmentation (kappa = 0.41, kappa(weighted) = 0.51) and increased pigment (kappa = 0.54, kappa(weighted) = 0.71). For drusen, agreement was moderate to substantial for presence/maximum size (kappa = 0.50, kappa(weighted) = 0.68), type (kappa = 0.61, kappa(weighted) = 0.69), and area (kappa = 0.56, kappa(weighted) = 0.77). Six annual regrades of 119 eyes showed little temporal drift in grading of various age-related macular degeneration abnormalities, except for drusen type. CONCLUSIONS: The Age-Related Eye Disease Study has demonstrated satisfactory reliability for detecting onset of advanced age-related macular degeneration in a cohort, and moderate to substantial agreement on various abnormalities across the age-related macular degeneration spectrum. The Age-Related Eye Disease Study system for classification of age-related macular degeneration is suitable for longitudinal multicenter studies.

Cohort Studies↗
PubMed1992

Quantitative determination of the melanin contents in ocular tissues from human blue and brown eyes.

This paper deals with our findings on the quantities of melanin in the tissues from blue and brown eyes. The amount of melanin in the iris, ciliary body and retinal pigment epithelium-choroid was separately determined. The results are expressed as the amount of melanin in mg tissue as well as the amount of melanin in the whole tissue. The results showed that there was no statistically significant difference between the melanin content of the iris in blue and brown eyes. However the ciliary body and retinal pigment epithelium-choroid from brown eyes had more melanin than the corresponding tissues from blue eyes. Blue and brown eyes with higher colour intensity had more melanin than the corresponding eyes with lesser intensity of colour. It is suggested that the differences between brown and blue eyes in their melanin content may have relevance to the pharmacokinetics of drugs that bind to melanin. This would mean that the larger amounts of melanin would decrease the initial levels of the drugs and would increase the drug levels after prolonged periods.

Choroid↗
PubMed1999

Grating and plaid chrominance motion influences the suppressed ocular following response.

Involuntary eye movements to foveal stimulation were measured in a monkey while it performed a fixation task. Second-order plaid motion generated higher velocities of eye movements than did first-order gratings, yet the latency of the early following response was no different for grating or plaid motion. Nevertheless, early suppressed ocular following responses to isoluminant motion continue to be titrated by stimulus velocity and spatial frequency. Motion defined by 60% luminance contrast gratings and plaids generated a motion signal gain of 60% over chrominance motion. The 20% longer latency of eye movements to chrominance motion may reflect the longer conduction latency of the parvocellular channel and an additional stage in cortical processing en route to motion areas and eye movement control.

Analysis of Variance↗
PubMed1991

Correlation of some ocular and hematologic factors and intraocular pressure in an aged population.

Ocular status including gonioscopy was performed on 833 volunteers in the Kuopio Eye Survey (KEYS). Some systemic factors including arterial blood pressure, body mass index, blood hemoglobin and glucose were also screened. In regression analysis only systolic blood pressure, grade of trabecular meshwork pigmentation and sex had a statistically significant correlation to intraocular pressure.

Aged↗
PubMed1996

Visual pigment gene structure and the severity of color vision defects.

Rearrangements of the visual pigment genes are associated with defective color vision and with differences between types of red-green color blindness. Among individuals within the most common category of defective color vision, deuteranomaly, there is a large variation in the severity of color vision loss. An examination of specific photopigment gene sites responsible for tuning photopigment absorption spectra revealed differences that predict these variations in the color defect. The results indicate that the severity of the defect in deuteranomalous color vision depends on the degree of similarity among the residual photopigments that serve vision in the color-anomalous eye.

Blotting, Southern↗
PubMed1980

The 1976 accident experience of civilian pilots with static physical defects.

The 1974 and 1975 aircraft accident experiences of civilian pilots with eight selected static physical defects have been examined and reorted previously. Three categories--blindness or absence of either eye, deficient color vision with a waiver, and deficient distant vision--had significantly more accidents than were expected on the basis of observed-to-expected ratios. In 1975, accident rates were calculated. The rates for air men with blindness or absence of an eye were still found to be significantly higher. Observed-to-expected ratios for 1976 were 1.91 for deficient color vision with a waiver, 1.28 for contact lens users, 1.37 for blindness or absence of either eye, and 1.62 for deficient distant vision. The accident rates per 100,000 h of cumulative and last 6 months' flying experience were significantly greater for contact lens users and monocular pilots than for the active airman population. The other groups had no consistently significant differences.

Accidents, Aviation↗
PubMed2026

Additional PAX3 Variants for Dominant Blue Eyes in Cats.

Since the recent publication of the first feline variant of the PAX3 (Paired Box&#xa0;3) gene associated with blue eyes and minimal white spotting (DBE, Dominant Blue Eyes), three further variants of PAX3 have been reported in felines. However, these four variants do not account for all the different feline lines that exhibit DBE. Whole-genome sequencing using short-read and long-read technologies identified a large complex structural variant involving two deletions and an inversion in a purebred line of British shorthair and longhair cats. All 39 British cats with a BDE phenotype were heterozygous for the variant, that was absent in 47 non-DBE cats and 16 DBE cats from other breeding lines. The purebred British shorthair founder female named Nadeya was also heterozygous for the variant, and the segregation of the variant is consistent with dominant inheritance. We named this NC_058375.1:g.[205097674_207411974del;207411975_211290497inv;211290498_211387174del] variant the DBENAD (Nadeya Dominant Blue Eyes) allele. In addition, a candidate gene approach identified a nonsense variant, XM_019838731.3:c.784C>T, in the fifth exon of PAX3 in a second breeding line originating from a female named Marusya. The segregation of this nonsense variant is consistent with dominant inheritance, and a perfect genotype-phenotype correlation was observed in the 16 cats from this line, so we propose that this sixth variant of PAX3 represents the DBEMARU (Marusya Dominant Blue Eyes) allele in the domestic cat. Our study has identified two further variants of the PAX3 gene associated with DBE in domestic cats, which will help to improve genotyping of the breeding stock.

Animals↗