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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Preoperative contrast sensitivity functions (CSFs) were determined for 15 cataract patients using laser-generated patterns that effectively bypassed the optical components of the eye. These functions were compared with postoperative CSFs determined using traditional methods by transmission through the optics of the eye. Accurate prediction of postoperative contrast sensitivity occurred in 91% of the cases (ten of 11) for patients with preoperative visual acuity of 20/200 or better and in 67% of all the cases (ten of 15). Prediction failures occurred when the laser interferometer was not able to penetrate the cataract or when postoperative complications occurred. These results suggest that preoperative measurement of laser interferometric CSF is a useful predictor of postoperative CSF for patients with mild to moderate cataracts that can be bypassed by the laser and with better than 20/200 preoperative visual acuity. The problem of assessment when lens opacity is advanced is addressed in Part II.
J Cataract Refract Surg 1991 Jan
PMID:Assessment of potential contrast sensitivity. Part I: Preoperative prediction of contrast sensitivity following intraocular lens implantation. 200 57

The laser interferometer can effectively bypass the optics of the eye and measure retinal function in patients with immature cataracts. However, it is not known how much laser interferometric measurements are impaired by cataract density. In this study we compared objective lens opacity using the IntraOptics opacity lensmeter with contrast sensitivity (CS) measured by a Randwal He-Ne laser interferometer. Comparison of lens opacity with CS in the cataract population revealed an inverse linear relationship between objective lens opacity and retinal contrast sensitivity. Separation by cataract type showed correlation coefficients as high as -0.91 for nuclear sclerotic predominant cataracts and as low as no significant correlation for posterior subcapsular predominant cataracts. Comparisons of before and after implantation surgery contrast sensitivities (as measured by the laser interferometer) with preoperative lens opacities (as measured by the IntraOptics opacity lensmeter) quantified the extent to which laser interferometric measurements underestimated potential retinal function. We found that for all cataracts, other than posterior subcapsular predominant cataracts, potential contrast sensitivity (in decibels) was underestimated by about 0.2 to 0.3 times the opacity measured by this technique.
J Cataract Refract Surg 1991 Jan
PMID:Assessment of contrast sensitivity. Part II: The relationship between objective lens opacity and laser interferometric contrast sensitivity in the cataract patient. 200 58

We found a female cataractous DDD/1-nu/+ mouse and established a hairy mutant strain (DDD/1-Cti/Cti) with 100% incidence of cataract from it by repeating sibmating. Genetic studies demonstrated that a single autosomal semidominant gene controls cataractogenesis. This gene was named Cti. In homozygotes, DDD/1-Cti/Cti, the lenses began to opacify at 14 days of fetal life and were recognized clinically as cataract at 13-14 days of age when the eyes first open. The opacification became more and more intense with age and looked like mature cataract at 28-42 days of age. However, clarification of the opacified lenses commenced at the periphery after 56 days of age and expanded to the inside with time, and only an opaque spot was left at the center at 140 days of age. In heterozygotes, DDD/1-Cti/+, the lenses were recognizable as cataract after 28 days and became like mature cataract around 35 days of age. The opacity began to be lightened at 42 days and the lenses appeared normal at 56 days of age. Both lenses and eyeballs developed in similar courses in DDD/1(-)+/+, -Cti/+ and -Cti/Cti, although slightly retarded in the last. Microphthalmia was not accompanied even in DDD/1-Cti/Cti. The lens water content remained higher during the time when intense lens opacity continued in DDD/1-Cti/Cti and -Cti/+. Background genes appeared to affect the expression of Cti. DDD/1-Cti(-)+ mice may provide a model for researches into clarification of opaque lenses. A discussion concerning the possible allelism of Cti and Cts with Lop was made based on their phenotypic characteristics.
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PMID:[Characterization of dominant hereditary cataract in DDD/1 mice]. 204 67

Data collected from 3646 eyes in the Italian-American Natural History Study of Age-Related Cataract were used to investigate whether the reliability of the Lens Opacities Classification System II (LOCS II) by the severity of the opacity that is being graded or is influenced by the presence and severity of coexisting opacities. Reliability was assessed by comparing the slit-lamp gradings of two clinical examiners (346 eyes) and the gradings performed at the slit lamp with gradings of photographs (3646 eyes). The severity of cortical and nuclear opacities did not affect the reproducibility of slit-lamp gradings, but clinical grading of posterior subcapsular opacities became more reliable as the severity of the posterior subcapsular opacities increased. More advanced coexisting opacities decreased the agreement in the slit-lamp diagnosis of nuclear, but not cortical or posterior subcapsular, opacities. Comparisons of clinical and photographic gradings showed very good to excellent agreement for nuclear and cortical opacities, regardless of the severity of the specific opacity or the severity of the coexisting opacities. Agreement in diagnosing posterior subcapsular opacities was decreased in eyes with milder posterior subcapsular opacities and in eyes with more severe coexisting nuclear and/or cortical opacities. The effect of the severity of the opacity being graded and the severity of coexisting opacities on the reliability of the LOCS II must be considered in studies that use the system to classify and grade cataracts.
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PMID:The effect of cataract severity and morphology on the reliability of the Lens Opacities Classification System II (LOCS II). 207 51

This report presents the results of a study designed to verify the influence of lens opacities on the visual field indices. Four age-matched groups of subjects were considered: healthy volunteers, glaucomatous patients without lens opacities, cataractous patients without glaucoma and glaucomatous patients with lens opacities. The quantification of lens opacities was performed with the Lens Opacity Meter 701 instrument. The visual field indices were obtained automatically from the G1 program of the Octopus system. The statistical analysis of the results (coefficient of correlation) has shown that only the visual field indices that correspond to uniform and diffuse loss of light sensitivity were influenced by the presence of cataract. On the contrary, the visual field indices that indicate local irregularities of the threshold were not significantly influenced by the presence of lens opacities.
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PMID:Influence of lens opacities on visual field indices. 207 54

The present study was undertaken to determine whether the scattered light of lenses measured with the Opacity Lensmeter 701 can be used for objective, quantitative assessment of lens opacities, and how far pupillary diameter and the type of lens opacity affect the measurement. Visual acuity and scattered light were determined in 150 eyes with the Opacity Lensmeter set at 700 nm. In the group with nuclear cataract there was a significant correlation between visual acuity and the amount of scattered light measured by the Lensmeter. In the groups with cataracta scutellaris posterior and cortical cataract there was no significant correlation between visual acuity and scattered light measurements. While the Interzeag Opacity Lensmeter 701 is capable of furnishing data on fairly large populations with nuclear cataract, it is of limited value for assessing individual cases. The influence of pupillary diameter on the scattered light measurement was examined in 50 selected eyes. In all 30 of the eyes with cataract, significant correlations were found between pupillary diameter and scattered light measurements, while this was the case in only 10 of the 20 normal eyes. Therefore, when measuring stray light in cataract cases, the pupillary diameter should be stated.
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PMID:[Cataract diagnosis using scattered light at 700 nm]. 208 51

The Nakano mouse is a hereditary cataract model whose most characteristic change is a deficiency in lens Na+,K(+)-ATPase. Consequently, there is a change in lenticular sodium and potassium ion levels just before cataract formation. The amounts of calcium ion also change suddenly in the lens, with accumulated levels higher than any other type of cataract. Other biochemical changes coincide with the development of lens opacity, including decreases in the levels of reduced glutathione, ATP, biosynthetic activity of proteoglycans in epithelial cells, and the permeability of gap junction channels in fiber cells. The decrease in the activity of Na+,K(+)-ATPase results in changes in a number of key metabolic parameters, resulting in the eventual opacification of the Nakano mouse lens at approximately 30 days of age.
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PMID:Hereditary cataract of the Nakano mouse. 219 7

The Interzeag 701 Lens Opacity Meter was used to study the lenses of 122 cataract eyes and 73 healthy eyes with clear lenses. The readings taken separately in 67 eyes by two different operators did not significantly differ. Statistically significant differences were found between the readings taken by the same operator when the pupil size was different in all types of cataract and also in eyes with transparent lenses. Opacity Meter readings correlate well with the visual acuity of eyes with nuclear and mixed cataracts, but no correlation was found in eyes with cortical or posterior subcapsular cataracts. In healthy eyes with clear lens, a correlation was found between the instrument readings and age.
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PMID:Evaluation of the 701 interzeag lens opacity meter. 222 89

The contribution of cataract to the decrease of visual field in patients with glaucoma is difficult to ascertain. To attempt to quantitate the change in visual field due to cataract, we examined 27 eyes of 26 patients before and after cataract extraction. The examination consisted of measurement of best refraction with visual acuity, visual field testing with the pupil dilated, measurement of lens opacity, determination of the intraocular pressure, and evaluation of the character of the cataract before surgery and of the posterior capsule after surgery. The results reaffirmed the detrimental effect that cataract may have on the visual field but also showed that the heterogeneity of cataracts limits the usefulness of the lens opacity meter in quantitating the extent of visual field loss due to cataract.
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PMID:Lens opacity as a predictor of visual field impairment due to cataract. 224 64

The Hong Kong 1981 Census found a high prevalence of blindness in the age group aged 65 and above. Visual defects short of blindness are also a special problem among the elderly and cataract is one of the most important causes. We have studied the prevalence of cataract among 546 subjects living in homes or hostels for the aged in a New Town in Hong Kong. Cataract was defined as having a lens opacity and visual acuity worse than 20/100 in either eye. A prevalence of 45% among men and 32% among women was found. There was significant difference in prevalence between men and women aged below 75 but little sex difference was noted for the older age groups. Among the cataract cases detected on screening, about half had not had the diagnosis made previously. The results confirm the need for more epidemiological and health care studies on the visual problems among the aged.
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PMID:Prevalence of cataract among the institutionalized elderly in Hong Kong. 225 24


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