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)

In a double-blind study a non-invasive method of examining the stability of the precorneal tear film was used to record tear thinning time on a population of 34 independently diagnosed dry eye patients. The results were compared with those for tear output, as inferred from the standard Schirmer tear test, and a correlation coefficient of 0.20 determined. The mean tear thinning time and Schirmer results for the population sample were 6.87 +/- 2.97 sec, and 5.62 +/- 5.69 mm wetting in 5 min, respectively. From a plot of tear thinning time against Schirmer a simple classification for dry eyes can be made. A Type A with normal tear stability and low output accounting for 14.70% of the dry eyes. A Type B with low tear stability and normal output, also accounting for 14.70% of the dry eyes. A Type C with low stability (less than 9.84 sec), and low output (less than 11.31 mm wetting in 5 min) accounting for 70.60% of the dry eyes.
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PMID:A classification for dry eyes following comparison of tear thinning time with Schirmer tear test. 163 98

Blinking involves high rates of shear within the tear film, requiring a low tear viscosity to avoid damage to epithelial surfaces. Conversely, in the open eye, a higher viscosity is desirable to resist drainage and film break-up. Samples of human tears were collected with moderate stimulation from 5 adult males, 3 with normal and 2 with marginally-dry eyes. The apparent viscosity at 22 degrees C was found using a Couette-type rheometer over the range of shear rate 2-160 sec-1. Marked shear-thinning was apparent in all samples, with little apparent difference between normal and dry-eye tears. Although a power-law equation could be fitted over part of the range, analyses according to either the Casson plastic model as used for rabbit tears (with a low yield-point indicative of some very loose initial gel-like structure) or the Steiger-Ory model (a true pseudoplastic model with no initial yield point) were inconclusive over the range of shear rate studied. The descriptive model of Cross gave zero-shear viscosity values of 4.4, 7.1 and 8.3 mPa.sec for normal tears, and 27.1 and 31.1 mPa.sec for dry-eye tears; the corresponding time constants were 0.13, 0.27 and 0.38 sec for normal tears, and 2.7 and 2.9 sec for dry-eye tears. These time-constants can be considered as an approximate relaxation time, indicating the time taken for the tear film to stabilise after a blink.
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PMID:The viscosity of human tears. 177 67

The major histopathologic changes seen in the eyes of patients undergoing bone marrow transplantation involve the conjunctiva, cornea, choroid, and lacrimal gland. The major finding in the conjunctiva is keratinization. The major findings in the cornea are epithelial thinning and keratinization. Keratinization of the conjunctiva and cornea is associated with graft-v-host disease (GVHD) and may be either a primary manifestation of GVHD or be secondary to the "dry eye" syndrome that develops in patients with GVHD. Corneal epithelial thinning is probably secondary to the chemotherapy used in the preparative regimen. An unusual histiocytelike infiltrate is present in the choroid and appears to be associated with GVHD. In acute GVHD, lacrimal gland stasis occurs and is the probable cause of the dry eyes seen in these patients.
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PMID:The eye in bone marrow transplantation. II. Histopathology. 634 Jun 49

The dry eye syndrome is a chronic disease which can become a serious threat to useful vision. However, there is only a limited understanding regarding effective treatment or prevention of this disease. Establishing an effective mode of treatment requires the use of a satisfactory animal dry eye model. Ideally, such a model should rapidly determine the effectiveness of agents that inhibit the damaging effects of this syndrome. This paper presents a short-term dry eye model using rabbits, which combines mechanical prevention of blinking and methylene blue staining. This model is not intended to be a precise representation of the dry eye syndrome, since this disorder has recently become recognized to involve a primary pathological process of the corneal and conjunctival epithelium. However, by using this model, clinical signs of dry eye can be observed after a few hours in the form of acute desiccation. Corneal damage can easily be evaluated both qualitatively by methylene blue staining scores, and quantitatively by chronic assay. Visually observed corneal epithelial thinning was confirmed by scanning electron microscopy (SEM) to be due to loss of epithelial integrity. Using a 3% chondroitin sulfate solution, an already proven effective agent for dry eye, this model effectively demonstrated an 80% inhibition in the development of methylene blue positive lesion after a period of only 2 hours. This short term dry eye model is valuable in primarily screening the efficacy of potential therapeutic agents in the prevention and treatment of dry eye.
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PMID:Establishment of a rabbit short-term dry eye model. 857 13

The mucin secretagogue 15(S)-HETE was found to stimulate glycoprotein secretion in human ocular tissue at submicromolar concentrations in the present studies. Therefore, the ability of topically applied 15(S)-HETE to preserve corneal integrity was investigated in a rabbit model of desiccation-induced corneal defect. Desiccation-induced corneal injury was elicited in anesthetized rabbits by maintaining one eye open with a speculum. Corneal staining and corneal thickness changes were determined immediately following desiccation. 15(S)-HETE dose-dependently reduced corneal damage (ED50 = 120 nM) during a two-hour desiccation. Corneal staining was unchanged relative to control using a 1 microM dose of 15(S)-HETE. Through four hours of desiccation, 15(S)-HETE (500 nM) decreased corneal staining by 71% and completely prevented corneal thinning. 15(S)-HETE (1 microM) was significantly more efficacious than an artificial tear product over the 4-hour desiccation period. There was no evidence of tachyphylaxis following repeated topical ocular dosing of 15(S)-HETE. These studies demonstrate that 15(S)-HETE stimulates ocular mucin secretion in vitro and effectively protects the cornea in a rabbit model of desiccation-induced injury. The results suggest that the ocular mucin secretagogue 15(S)-HETE may have therapeutic utility in dry eye patients, alleviating corneal injury and restoring corneal integrity.
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PMID:Corneal protection by the ocular mucin secretagogue 15(S)-HETE in a rabbit model of desiccation-induced corneal defect. 1222 65

Dry eye is an ocular disease clinically associated with corneal epithelium damage and arises acutely or chronically from dehydration of the ocular surface. We provide herein a novel in vivo model of corneal epithelium damage, in which the corneal surface was entirely covered with a sugar powder to provoke the rapid removal of corneal surface liquid. In this animal model, such corneal damage as can be fluorometrically detected was observed immediately after 20-minute hyperosmotic treatment, reached a maximum 6 hours later, and then gradually declined to complete recovery at Hour 126. Recovery of the damaged corneas produced by hyperosmotic stress was significantly accelerated by treatment with 0.1% sodium hyaluronate, a dry eye remedy in Japan. Thinning or partial erosion of the epithelial cell layers was histopathologically demonstrated in and around the sugar powder-applied area but the posterior stromal cell layer remained intact, indicating that the present rabbit in vivo model may be used to conveniently screen therapeutics against acute ocular diseases with corneal epithelium damage. In addition, microscopic observations of TUNEL-stained thin-sections of the damaged corneas indicated that apoptotic cell death, but not any inflammatory reactions, may be at least partially responsible for the hyperosmolarity-induced destruction of the corneal epithelium.
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PMID:A convenient rabbit model of ocular epithelium damage induced by osmotic dehydration. 1282 46

A 33-year-old woman had progressive blurred vision 2 weeks after uneventful laser in situ keratomileusis surgery. Initial satisfactory uncorrected visual acuity (UCVA) was complicated by postoperative dry eye and drug toxicity. Slitlamp biomicroscopy revealed diffuse punctate epithelial keratitis and inferior corneal epithelial defect with rolled-up epithelium on the flaps and the inferior unoperated cornea in both eyes. Diffuse inflammatory cell infiltrates were evident in the stroma. Stromal thinning was evident on serial Orbscan (Bausch & Lomb) and pachymetry examinations, and a hyperopic shift of almost +6 diopters was observed in the refractive error in both eyes. These examinations showed a gradual recovery of stromal thickness after copious hydration with balanced salt solution. The UCVA was 1.0 in both eyes after corneal rehydration.
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PMID:Toxic keratopathy-related corneal dehydration after laser in situ keratomileusis. 1612 7

A method is described for recording interference images from the full thickness of the precorneal tear film (PCTF). Simultaneous images are recorded by two video cameras. One camera responds to broadband spectral illumination and records interference from the superficial lipid layer of the tear film. The other camera uses narrowband illumination and records interference from both the lipid layer and the full thickness of the PCTF. Thus the full-thickness interference fringes are derived from the difference between, or ratio of, narrowband broadband images. This method has the potential for evaluating the role of both tear film flow and evaporation in tear film thinning and breakup. It therefore may be applied to the analysis of dry eye disease.
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PMID:Interferometric imaging of the full thickness of the precorneal tear film. 1691 36

To describe a case of bilateral cicatrizing keratoconjunctivitis in a patient with lichen planus and review the literature. Conjunctiva cicatrization with symblepharon formation, dry eye, corneal infiltration and neovascularization and thinning were the most observed prominent signs. Diagnosis was based on clinical findings and biopsy, after exclusion of typical causes of cicatricial keratoconjunctivitis.
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PMID:[Lichen planus leading to bilateral cicatrizing keratoconjunctivitis: case report]. 1916 27

This paper reviews current knowledge of the pathophysiology of dry eye and predicts that the clinical picture in late disease differs in both severity and quality from that in early disease. It is hypothesized that hybrid forms evolve, in which aqueous-deficient dry eye (ADDE) takes on features of evaporative dry eye (EDE) and vice versa. As a consequence, early and late forms may require different diagnostic criteria and respond to different therapeutic regimes. Tear hyperosmolarity plays a key role in the damage mechanism of dry eye, and ADDE is recognized to be a low-volume, hyperosmolar state. As ADDE advances, a progressive decrease in lacrimal secretion occurs, exacerbated by loss of the corneal reflex. This causes a decrease in tear volume, thinning of the aqueous tear film, and retarded spreading of the tear film lipid layer. The latter is hypothesized to cause an increase in evaporative water loss and an added evaporative component to the dry eye. Thus, in advanced disease, the hybrid state would be an organic ADDE, accompanied by a functional EDE in the absence of meibomian gland dysfunction. This functional EDE would respond to agents that expand the tear volume, restore corneal sensitivity, or provide an artificial tear film lipid layer.
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PMID:Predicted phenotypes of dry eye: proposed consequences of its natural history. 1938 77


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