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Results for “CORNEAL OPACITY”

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At least 127 records · Page 7Linked to original sources
PubMed2000

Corneal opacity in lumican-null mice: defects in collagen fibril structure and packing in the posterior stroma.

PURPOSE: Gene targeted lumican-null mutants (lum(tm1sc)/lum(tm1sc)) have cloudy corneas with abnormally thick collagen fibrils. The purpose of the present study was to analyze the loss of transparency quantitatively and to define the associated corneal collagen fibril and stromal defects. METHODS: Backscattering of light, a function of corneal haze and opacification, was determined regionally using in vivo confocal microscopy in lumican-deficient and wild-type control mice. Fibril organization and structure were analyzed using transmission electron microscopy. Biochemical approaches were used to quantify glycosaminoglycan contents. Lumican distribution in the cornea was elucidated immunohistochemically. RESULTS; Compared with control stromas, lumican-deficient stromas displayed a threefold increase in backscattered light with maximal increase confined to the posterior stroma. Confocal microscopy through-focusing (CMTF) measurement profiles also indicated a 40% reduction in stromal thickness in the lumican-null mice. Transmission electron microscopy indicated significant collagen fibril abnormalities in the posterior stroma, with the anterior stroma remaining relatively unremarkable. The lumican-deficient posterior stroma displayed a pronounced increase in fibril diameter, large fibril aggregates, altered fibril packing, and poor lamellar organization. Immunostaining of wild-type corneas demonstrated high concentrations of lumican in the posterior stroma. Biochemical assessment of keratan sulfate (KS) content of whole eyes revealed a 25% reduction in KS content in the lumican-deficient mice. CONCLUSIONS: The structural defects and maximum backscattering of light clearly localized to the posterior stroma of lumican-deficient mice. In normal mice, an enrichment of lumican was observed in the posterior stroma compared with that in the anterior stroma. Taken together, these observations indicate a key role for lumican in the posterior stroma in maintaining normal fibril architecture, most likely by regulating fibril assembly and maintaining optimal KS content required for transparency.

Animals↗
PubMed1979

Crystalline corneal opacities in the Siberian Husky.

Bilaterally symmetric opacities were detected in the corneal stroma of 78 (14%) of 560 Siberian Huskies, aged 7 months to 12 years, examined in ophthalmology screening clinics. The opacities were round or horizontally oval and consisted of a diffuse gray homogeneous haze in the anterior stroma or an array of fine polychromatic crystals in the posterior stroma, or both. The corneas were not inflamed. The frequency of occurrence and density of the opacities increased with age. Several affected dogs were closely related, but a specific inheritance pattern could not be established. Light and electron microscopy disclosed clusters of extracellular, thin, needle-shaped, crystalline clefts. Histochemical stains on frozen sections identified neutral fats, phospholipids, and cholesterol as components of the crystals.

Animals↗
PubMed1989

Corneal opacity in canine MPS I. Changes after bone marrow transplantation.

Corneal opacification associated with glycosaminoglycan (GAG) deposition occurs in canine mucopolysaccharidosis I (MPS I), a deficiency of the lysosomal enzyme alpha-L-iduronidase. In affected dogs corneal lesions appear similar to those in children with the same disease. Transplantation of bone marrow from unaffected littermates was performed in 5 MPS I affected dogs at 5 months of age. In three recipients that became long-term survivors corneal clouding was largely alleviated compared to affected control dogs. In no case, however, did the corneas remain totally clear throughout the course of the study (594, 628 and 1425 days). Light and electron microscopic findings correlated with the clinical impression of partial improvement. Glycosaminoglycan analysis of corneal tissue from two transplant recipients, one normal littermate, and one MPS I-affected, untransplanted dog showed quantitative and qualitative changes in stored GAG following bone marrow transplantation.

Animals↗
PubMed1989

Late corneal opacities in the syndrome of interstitial keratitis and vestibulo-auditory symptoms.

Progressive clouding of the cornea may be a delayed complication of the interstitial keratitis-vestibuloauditory syndrome. Two illustrative cases are presented. The first case illustrates progressive opacification about aberrant vessels in the deep stroma presenting a characteristic dendritiform pattern. The second case shows that the opacification is due, in this case at least, to formation of connective tissue with inclusion of lipid crystals and fat along with the blood vessels. Descemet's membrane is also thickened several fold.

Adult↗
PubMed1997

[The effect of tranilast on subepithelial corneal opacity after excimer laser keratectomy].

Recent studies have reported that tranilast inhibited in vitro the proliferation of keratocytes from corneal subepithelial opacities (haze) and collagen synthesis in cultured corneas after excimer laser photorefractive keratectomy (PRK). In this study 0.5% tranilast eye drops, 0.1% betametazone phosphate eyedrops, and a 0.5% tranilast base solution (control) were administered four times daily to rabbits which had undergone PRK. Weekly evaluation of the inhibitory effect of these drugs on haze began two weeks after surgery according to Fantes' classification. 0.5% tranilast suppressed haze from six weeks to thirteen weeks after PRK (p < 0.05). 0.1% betametazone phosphate showed no effect. These results suggested that 0.5% tranilast had a satisfactory therapeutic effect on haze after PRK.

Animals↗
PubMed2003

Corneal opacity and cataract: triple procedure versus secondary approach.

PURPOSE: To determine the efficacy of planned secondary cataract surgery after keratoplasty. METHODS: Twenty patients (22 eyes) with simultaneous corneal pathology and cataract were enrolled in a prospective, interventional, case-matched, nonrandomized comparative trial. Penetrating keratoplasty (PKP) and extracapsular cataract extraction (ECCE) with IOL insertion (triple procedure) were performed in 11 eyes, and planned phacoemulsification (PEA) with IOL insertion after PKP was performed in 11 case-matched eyes. RESULTS: There were 10 eyes (91%) within +/-2.0 D of expected values in the secondary PEA group versus 5 patients (45%) in the triple procedure group. No difference was observed in endothelial cell density after 1-year follow-up. CONCLUSIONS: Planning for secondary PEA in PKP patients with cataracts is a safe and reliable procedure to obtain less post surgical refractive error. Performing a two-stage intervention has no effect on corneal endothelial viability after 1 year.

Adult↗