Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Specimens of a cornea, conjunctiva and iris were removed at the time of penetrating keratoplasty in a case of nephropathic cystinosis. Immunohistochemical studies revealed the presence of class II antigens on the stromal keratocytes of the cornea and the vascular endothelial cells, pericytes and fibroblasts of the conjunctiva. In addition, there were thinning and focal breaks in Bowman's membrane. Both of these findings may have contributed to the severe photophobia and blepharospasm seen in patients with longstanding cystinosis.
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PMID:Nephropathic cystinosis: immunohistochemical and histopathologic studies of cornea, conjunctiva and iris. 358 80

Our computer-based corneal topography analysis system was used to study the keratoscope photographs (keratograms) from two patients with classic pellucid marginal degeneration and a third patient with no inferior corneal thinning, whose keratoscope mire pattern was suggestive of the condition. All three patients showed marked flattening of the central cornea along a vertical axis and marked steepening of the inferior corneal periphery, which also extended into mid-peripheral inferior oblique corneal meridians. The mid-peripheral cornea gradually decreased in power above the inferior oblique meridians.
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PMID:Corneal topography of pellucid marginal degeneration. 360 67

In the prospective Basel longitudinal study on aging (1955-1978) 123 men (age at entry from 6-61 years) were investigated in 2 year (average) intervals. Complete case histories are available on 67 subjects over the entire period (19.6 +/- 0.85 years). Part I of the study was to confirm the hypothesis of Bernstein and of Steinhaus, according to which life expectancy can be estimated from the speed of development of presbyopia. Parallel to the measurement of accommodation range (after preliminary determination of refraction and visual acuity), the development of height, body weight, vital capacity, expiratory volume, chest circumference, abdominal circumference, blood pressure, ECG and pulse wave velocity were measured. Invasive investigations were not undertaken. Only when hypertension was combined with obesity was the diminution of accommodation range striking (Fig. 10c; however there were only 3 subjects in this risk group). Taking everything into consideration there was a concomitance between decrease of accommodation range and changes of medical parameters (Table 6). Intercurrent illness did not influence the accommodation range. Longitudinal measurements and cross-sectional comparisons (data averaged to the same point as of the same age) were carried out. The results did not always coincide. We could not confirm the hypothesis of Bernstein and of Steinhaus. In Part II the results of the objective measurements are given. Apparently growth of the skull does not stop entirely. The increase of interpupillary distance can be complete at 17 years of age, but also can continue to the 30th year. The palpebral fissure increases an average of 3 mm more horizontally between the 6th and the 20th year of life. The corneal diameter remains constant in all age classes, that is, the growth of the cornea should be complete before the 6th year of life. Early arcus senilis changes are found already in the 20-year-old. The increase in the course of time of arcus senilis is obvious, it is most pronounced in obese hypertensives. Still there are persons who at 65 years of age show no arcus senilis. In the 20th year degenerative deposits in the conjunctiva begin. They increase in number and above the 60th year all subjects showed degenerative deposits. Aqueous veins are less visible in younger subjects. With increasing age--as a result of degenerative thinning of the conjunctiva--they are recognizable in ever greater numbers. The depth of the anterior chamber attains its greatest extent between the 20th and the 30th year.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The Basel longitudinal study on aging (1955-1978). Ophthalmo-gerontological research results. 362 22

The endothelial cells of the C57BL/6J mouse cornea show a progressive age-related increase in cell area, and an increasing departure from the initial hexagonal form. Mean endothelial surface areas were 304, 386, 458, 499, and 653 micron2 for mice of ages 1, 4, 11, 22, and 27 months, respectively. Increasing cell areas are interpreted to represent a spreading and thinning of surviving cells to compensate for cell loss. These age-related changes correspond to those previously observed in the rat, although the rat endothelial cells tend to have smaller cell areas and show less variation at each age studied.
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PMID:Age-related changes in the corneal endothelium of the mouse. 374 74

Pairs of rabbit corneas were perfused and corneal thickness monitored. The epithelial side of the preparation, and after stabilization also the endothelial side, was covered with silicone oil. A constant thinning of the cornea was observed at a rate of 11.1 microns hr-1 (= 1.0 micron L h-1 cm-2) S.D. 2.1, n = 9. This thinning was also present after endothelial removal: 12.3 microns hr-1, S.D. 1.6 (n = 5). Epithelial abrasion virtually abolished the thinning (2.5 microns hr-1, S.D. 1.89, n = 4), as did cooling from 34 to 0 degrees C. When the preparation was perfused with a Cl-free solution (SO4(2-) instead of Cl-, corrected for osmolarity with sucrose) no significant thinning of the preparation was observed (2.4 microns hr-1, S.D. 2.49, n = 4) after covering both surfaces with silicone oil. This simple set of experiments quantified the epithelial pump mechanism. The epithelial pump rate of about 1.2 microns L hr-1 cm-2 has to be taken into account when endothelial pump rates are measured in the in vitro preparation with intact epithelium.
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PMID:Corneal epithelial Cl-dependent pump quantified. 380 57

The effects of long-term extended wear of soft contact lenses on the human cornea were determined by examining 27 patients who had worn a high water content hydrogel contact lens in 1 eye only for an average of 62 +/- 29 months (mean +/- SD). The other eye, which was either emmetropic or amblyopic, acted as a control. The lens-wearing eye showed a 14.8% reduction in epithelial oxygen uptake (P less than 0.001), a 5.6% reduction in epithelial thickness (P less than 0.05), a 2.3% reduction in stromal thickness (P less than 0.05), the induction of epithelial microcysts, and a 22.0% increase in endothelial polymegathism (P less than 0.001). Endothelial cell density was unaffected by extended lens wear. No interocular differences in any of these physiological characteristics were found in a matched control group of anisometropic and amblyopic subjects who did not wear contact lenses. The patients ceased lens wear for up to one month and recovery of corneal function was monitored during this period. Epithelial oxygen uptake and thickness recovered within 33 days of lens removal. The number of microcysts increased over the first 7 days, but decreased thereafter; some microcysts were still present 33 days after lens removal. Recovery from stromal thinning had not occurred after 33 days following lens removal. There was a slight reduction in polymegathism in some patients, but overall this was not statistically significant. These findings establish (1) that the extended wear of hydrogel lenses induces significant changes in all layers of the cornea; (2) that lens wear suppresses aerobic epithelial metabolism, which may compromise the epithelial barrier to infection; and (3) that changes to the stroma and endothelium are long-lasting. Lens-induced effects on corneal physiology can be minimized by fitting lenses that have greater oxygen transmissibility (are thinner), are more mobile, more frequently removed, and more regularly replaced.
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PMID:Effects of long-term extended contact lens wear on the human cornea. 386 8

Keratoglobus is a bilateral corneal disease characterised by thinning and protrusion of the entire corneal surface. The cornea is of normal size and usually transparent. Acute corneal edema due to rupture of Descemet's membrane and perforation even from minimal trauma are the most frequent complications. Keratoglobus may be associated with blue sclera, hyperextensibility of the joints or auditory problems. Most often it is a congenital disease with autosomal recessive transmission, but it may be secondarily acquired to an advanced keratopathy (keratoconus), to trauma or to exophthalmos. We report 5 cases of keratoglobus. 4 patients underwent penetrating keratoplasty. The anatomical abnormalities of congenital keratoglobus (3 cases) are constants : an absent Bowman's membrane, a disorganized stroma containing granular material, a thickened, striated Descemet's membrane with breaks, folds and verrucosities. On the other hand, acquired keratoglobus (1 case) shows localised breaks in Bowman's membrane resembling those of keratoconus. The anatomopathological differences are discussed.
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PMID:[Keratoglobus]. 388 24

A 70-year-old female developed a bacterial ulcer in a previously rejected corneal graft. Cultures identified the pathogen as Enterobacter cloacae. Intensive topical antibiotic therapy arrested the progress of the ulcer, and the epithelial defect healed in one week; there was no resultant stromal thinning. Factors which may have predisposed the cornea to ulceration by this organism of relatively low virulence include chronic oedema following graft rejection, topical corticosteroid therapy, and tear insufficiency.
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PMID:Enterobacter cloacae ulceration in a failed corneal graft: a case report. 389 27

Specular microscopy was used to measure thickness changes of stroma-endothelium preparations from rabbit corneas in vitro. The preparations were first bathed on both sides for 90 min with different bicarbonate-Ringer solutions (2 to 50 mM bicarbonate) maintained in equilibrium with 5% CO2-air (pH 6.2 to 7.9). During this equilibration, the stroma attained a stable thickness that was inversely related to the hydrostatic pressure (20 to 100 cm H2O) applied to the endothelial surface. After equilibration and at 20 cm H2O pressure, covering the anterior stromal surface with silicone oil (Dow Corning 200 dielectric fluid, 20 cs viscosity) resulted in stromal thinning. The rate of this deturgescence increased (from 5 to 75 micron/h) as the equilibration solution bicarbonate level increased from 2 to 30 mM. The net size of the thickness change was also related to the equilibration bicarbonate level. However, indirect studies on the cornea using phenol red indicator and pH electrode measurements of solutions revealed that the stromal bathing solutions became more alkaline under the silicone oil layer. CO2 is soluble in silicone oil. Implications of these CO2 and pH effects on mechanisms of corneal deturgescence are discussed.
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PMID:New observations on bicarbonate-pH effects on thickness changes of rabbit corneas under silicone oil in vitro. 393 62

Intraocular silicone oil tamponade is being used with increasing frequency as an adjunct to conventional vitrectomy techniques in the treatment of proliferative vitreoretinopathy. When used in patients with aphakia, corneal decompensation is a common long-term complication. In this study, we evaluated the clinical and morphologic changes that occurred in the corneas of 14 rabbits and seven cats when the anterior chamber was filled with silicone oil. Within six days, wide-field specular microscopy showed a 40% reduction in endothelial density in the area of the silicone oil bubble in both groups. Progressive stromal thinning occurred in the rabbit cornea, with gradual development of a retrocorneal membrane at the junction of silicone-endothelial cell contact. In contrast, persistent stromal edema, peripheral vascularization, irregular plaques on the endothelium, and eventual epithelial ulceration and corneal thinning occurred in cat eyes.
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PMID:The effect of silicone oil on the cornea. 397 81


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