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At least 19 recordsLinked to original sources
PubMed1992

Analysis of IL-6 levels in human vitreous fluid obtained from uveitis patients, patients with proliferative intraocular disorders and eye bank eyes.

Several studies suggest a role for IL-6 in the pathogenesis of uveitis. Earlier we have shown that aqueous humour obtained from patients with uveitis contained raised levels of IL-6. In the study described here we investigated the IL-6 levels in vitreous fluid samples obtained from 75 uveitis patients with different uveitis entities. Vitreous samples from 14 patients with proliferative intraocular disorders (PID) and 29 eye bank eyes were used as controls. All the samples were tested in the IL-6 B9 bioassay as well as in a sensitive ELISA for IL-6. Raised IL-6 levels were detected in the vitreous fluid of uveitis patients as well as patients with PID, implicating IL-6 as a common inflammatory mediator. The highest mean level of IL-6 was found in the vitreous fluid of patients with acute retinal necrosis. The mean IL-6 levels measured by the ELISA were higher compared to the levels measured by the B9 bioassay. This may be caused by the presence of B9 bioassay inhibitory factors in the vitreous fluid of these patients.

Biological Assay↗
PubMed1978

The effect of suture depth on outflow facility in penetrating keratoplasty.

Outflow facility was measured in human eye bank eyes following penetrating keratoplasty (PKP) and cataract extraction. After measuring baseline outflow facility, a PKP and lens extraction was performed with the corneal button replaced by both interrupted "through-and-through" sutures and a conventional mid-to-deep stromal running suture. Outflow facility was unchanged from baseline with both sutures. However, following removal of through-and-through sutures outflow facility decreased 37%. This same suturing procedure was repeated in a second group of phakic eyes in which suture depth did not influence outflow facility.

Cataract Extraction↗
PubMed1979

Carbon dioxide laser scleral dissection and filtering procedure for glaucoma.

A comparison of eye bank eyes using continuous wave or rapid superpulsed carbon dioxide laser energy indicated that rapid superpulsed was the superior modality for scleral dissection, because there is less charring and puckering of tissue. The results of filtering procedures in five glaucomatous eyes by using rapid superpulsed carbon dioxide energy to perform the scleral dissection revealed the possible advantages of performing the procedure this way might be: (1) the technical ease by which the microdissection is performed under direct microscopic observation with the absence of blood or instruments in the field; (2) the safety factor of never having penetrated into the anterior chamber with a sharp instrument; (3) the possible advantage of the inhibition of healing at the wound margin because of coagulation of tissue at the wound edge by the laser beam; and (4) the bacteriocidal effect of thermal cutting.

Carbon Dioxide↗
PubMed1992

Age-related changes of sulfated proteoglycans in the normal human trabecular meshwork.

Ultrastructural changes in sulfated proteoglycans were studied in 12 pairs of normal eye-bank eyes (aged 1 day to 92 years), using the cationic dye, cuprolinic blue, in a 'critical electrolyte concentration'. Pretreatment of trabecular meshwork sections with various glycosaminoglycanases and nitrous acid served to characterize these proteoglycans. Three sizes of proteoglycan-cuprolinic blue (PG-CB) complexes were found in association with different extracellular matrix components. Small, thin PG-CB complexes were closely associated with collagen fibrils. Large, thick PG-CB complexes, although located close to collagen fibrils in a variety of places, were most commonly seen between the boundaries of the collagen bundles, where they were associated with fine filaments. Both types of collagen-associated PG-CB complexes contained chondroitin sulfate and dermatan sulfate, with dermatan sulfate predominant. Basal lamina-associated PG-CB complexes contained heparan sulfate. An age-related, progressive coalescence of collagen was found in normal trabecular meshwork in a statistically significant fashion; the regions of collagen coalescence were associated with a decrease of small, collagen-associated PG-CB complexes and an increase of a previously unrecognized matrix material. The measurement of areas of coalescence of collagen was used as an indirect indicator of small, collagen-associated PG-CB complex loss with age. Large collagen-associated PG-CB complexes and basal lamina-associated PG-CB complexes decreased from infant to young adult; no additional loss with age was found. Further studies will be needed to determine whether loss of sulfated PGs plays a role in increased aqueous outflow resistance that characterizes glaucoma.

Aging↗
PubMed1992

Trabeculectomy without conjunctival incision.

A trabeculectomy technique with conventional instruments, but without conjunctival incision or intracameral manipulation, was completed in 12 eye-bank eyes, two cat eyes, and in five patients with glaucoma. A partial-thickness limbal corneal flap provided access to an intrastromal limbal pocket through which the subconjunctival space was entered with an irrigating cystotome. The anterior chamber was entered at the surgical corneoscleral limbus beneath the corneal flap and the peripheral iridectomy was completed without difficulty. Full-thickness or guarded limbal fistulas could be created. Guarded limbal fistulas were completed in five of five patients with glaucoma. The technique produced low-lying, diffuse filtration blebs that persisted throughout the three-month postoperative period and reduced mean intraocular pressure from 33 to 12 mm Hg. Corneal trabeculectomy holds promise as a method for a filtration operation that does not require conjunctival incision, intracameral manipulation, or costly technology.

Aged↗
PubMed1992

Corneal topographic changes over time after radial keratotomy.

Radial keratotomy flattens the cornea, but in a nonuniform fashion. We used computer-assisted topographic analysis to examine curvature changes in different regions of the cornea. Within 45 days after surgery in human eyes, the central and midperipheral cornea flattens and the periphery steepens. Shortly after surgery, the central cornea (within 1-1.5 mm of the corneal light reflex) is steeper than the adjacent midperipheral cornea (1.5-3 mm peripheral to the light reflex). With time, however, the central cornea flattens more than the midperiphery, such that it is no longer relatively steeper. This regional variability in corneal curvature after radial keratotomy helps explain phenomena such as multifocal lens effect after radial keratotomy, and the changes with time account for the conflicting results observed clinically in human corneas and experimentally in human eye bank eyes.

Adult↗
PubMedDate not supplied

Intrastromal photorefractive keratectomy with a new optically coupled laser probe.

BACKGROUND: Intrastromal photorefractive keratectomy is a new procedure in which compact linear or area regions of the corneal stroma can be vacuolized, yielding changes in corneal curvature. METHODS: Diffraction-limited 1064-nanometer light pulses from a high rep rate Q-switched Nd-YAG laser were coupled through novel means into a probe with index-matched optical contact with the cornea. The resulting extremely reduced focal region initiated a plasma point that was free of shock front effects where tissue was reduced to liquid. This probe process was applied to the corneas of eye-bank eyes, and to living rabbit and primate eyes. The refractive effects were evaluated with slit-lamp microscopy, keratoscopy light and electron microscopy. RESULTS: Refractive effects similar to refractive keratotomy were observed immediately after treatment. Intrastromal highly localized vacuolized regions were observed at the depth of focus with variability of only 20 microns. The plasma point vacuoles were about 100 microns in diameter. Stromal material that occupied the vacuole space appeared completely reduced to liquid. The transition region between vacuole and normal tissue was less than 0.5 microns. The treatment vacuoles disappeared to the unaided eye 24 to 48 hours after treatment. CONCLUSIONS: Corneal refractive power can be achieved with intrastromal keratectomy.

Animals↗
PubMed1992

Corneal surface after deepithelialization using a sharp and a dull instrument.

Manual removal of the corneal epithelium currently precedes excimer laser photorefractive keratectomy. To assess the smoothness of the corneal surface following this procedure, six paired human eye-bank eyes (12 eyes) were manually deepithelialized using a blunt instrument (Paton spatula) on one eye and a sharp instrument (surgical blade) on the contralateral eye; all deepithelializations were done by the same surgeon. The 12 corneas were then resected and processed in an identical fashion for scanning electron microscopy. The microphotographs obtained showed that among the corneas deepithelialized with the blunt spatula, two had a smooth surface, and four had variable amounts of residual epithelial cells and basement membrane, confirmed by light microscopy. The surface of five corneas deepithelialized with the sharp instrument were slightly rougher than the former, with occasional linear scratches; one cornea retained a small amount of basement membrane. Removal of epithelium appears to be more complete when a sharp instrument is used. These findings may have clinical relevance, since residual epithelium and basement membrane after deepithelialization may influence the depth of ablation subsequently achieved with the excimer laser.

Basement Membrane↗
PubMed1992

Growth of human corneal endothelium on altered Descemet's membrane.

To determine whether Descemet's membrane (DM), which is altered by disease, interferes with endothelial cell growth, healthy human corneal endothelial cells were seeded onto DM from normal corneas and diseased corneal buttons from patients with Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy (PBK). DM was first peeled off the corneal specimens and the endothelial cells removed by trypsinization. A suspension of first-passage corneal endothelial cells (2,000 cells/microliters; obtained from donor eye bank eyes and grown in Dulbecco's minimal essential medium with 10% fetal bovine serum and 1.5% chondroitin sulfate) were seeded on DM. Epidermal growth factor (10 ng/ml) and insulin (1 U/ml) were added to the medium after seeding cells on the DM. The cells attached and flattened within 1 hour and reached confluency in 1 week on normal DM. Cells grown on DM from corneas of patients with Fuchs' endothelial dystrophy also flattened and grew to confluency in 1 week. Cells grown on DM from corneas of patients with PBK did not grow to confluency. Further studies with bovine and rabbit corneal endothelial cells showed similar growth pattern to human cells. These data indicate that DM from corneas of patients with Fuchs' dystrophy does not interfere with the growth of corneal endothelial cells but that DM from corneas of patients with PBK does interfere with cell growth.

Animals↗