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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Fluorescein is perhaps the most commonly used substance to visualize tear film thickness and dynamics; better understanding of this process aids understanding of dry eye syndrome which afflicts millions of people. We study a mathematical model for tear film flow, evaporation, solutal transport and fluorescence over the exposed ocular surface during the interblink. Transport of the fluorescein ion by fluid flow in the tear film affects the intensity of fluorescence via changes in concentration and tear film thickness. Evaporation causes increased osmolarity and potential irritation over the ocular surface; it also alters fluorescein concentration and thus fluorescence. Using thinning rates from in vivo measurements together with thin film equations for flow and transport of multiple solutes, we compute dynamic results for tear film quantities of interest. We compare our computed fluorescent intensity distributions with in vivo observations. A number of experimental features are recovered by the model.
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PMID:Computed flow and fluorescence over the ocular surface. 2903 9

Tear film thinning, hyperosmolarity, and breakup can cause irritation and damage to the human eye, and these form an area of active investigation for dry eye syndrome research. Recent research demonstrates that deficiencies in the lipid layer may cause locally increased evaporation, inducing conditions for breakup. In this paper, we explore the conditions for tear film breakup by considering a model for tear film dynamics with two mobile fluid layers, the aqueous and lipid layers. In addition, we include the effects of osmosis, evaporation as modified by the lipid, and the polar portion of the lipid layer. We solve the system numerically for reasonable parameter values and initial conditions and analyze how shifts in these cause changes to the system's dynamics.
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PMID:Duplex Tear Film Evaporation Analysis. 2909 37

Introduced in 2008 and subsequently popularized in South Korea, cosmetic eye whitening has been offered as a treatment of chronic conjunctival hyperemia. Patients undergo conjunctivectomy with topical mitomycin C (MMC) 0.02% application to achieve a whitened appearance from bleaching of avascular sclera. Much speculation has arisen from this procedure given the limited available evidence on its efficacy and safety. A literature search was performed to review common complications of cosmetic eye whitening, including chronic conjunctival epithelial defects, scleral thinning, avascular zones in the sclera, dry eye syndrome, and diplopia requiring strabismus surgery. Informing the general public of the risks of this procedure is of great importance for dermatologists and other cosmetic surgeons.
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PMID:Complications of cosmetic eye whitening. 2912 Nov 40