摘要:

We examined the surface epithelium of 30 eyes with color specular microscopy at 3-month intervals 1–18 months following penetrating keratoplasty. At least three examinations were performed on most eyes. We found a vortex keratopathy to be present in 70% of these eyes. In nine eyes, this vortex pattern was present at every examination, and in 12 eyes, it was present at some examinations and not at others. There was no vortex pattern seen at any examination in nine eyes. We also found alterations in the normal epithelial morphology around sutures and at the wound margin, with palisading parallel to the sutures and perpendicular to the wound edge. This altered morphology was also demonstrated by digitization of cells for shape and size, which showed significant differences compared with normals. We conclude that the morphology of the epithelial cells on the surface of the cornea remains abnormal for up to 18 months following penetrating keratoplasty.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The incidence of ulceration and perforation in the cornea of alkali-injured eyes is significantly reduced by treatment with trisodium citrate or sodium ascorbate. Topical citrate reduces the inflammatory response in the cornea by inhibiting polymorphonuclear leukocytes. Topical ascorbate elevates the depressed level of this vitamin in the alkali-injured cornea, reversing a scorbutic condition. The purpose of the current study was to determine whether combined treatment with topical citrate and ascorbate has an additional therapeutic value when compared with citrate alone. Adsorbotear without EDTA was used as the vehicle for both medications. Rabbit eyes were injured with IN NaOH for 35 s using a 12-mm well and were rinsed. Group I (47 eyes) received two drops of 10% citrate every hour on the hour and Adsorbotear on the half-hour for 14 h/day. Group II (48 eyes) received two drops of 10% citrate every hour on the hour and 10% ascorbate every hour on the half-hour for 14 h/day. The citrate/ascorbate group had significantly fewer ulcerations during the experiment than did the group receiving citrate alone (2 of 48 versus 10 of 47, 0.01 < p < 0.02). Both anterior ulcers in the citrate/ascorbate group and five ulcers in the citrate group healed to no ulcer by the end of the experiment (0 of 48 versus 5 of 47, 0.02 < p < 0.05). The average depth of ulceration was significantly less for the citrate/ascorbate group (p < 0.001). No descemetoceles or perforations were observed in either group. No differences were observed between the two groups with respect to the onset of ulceration or the number of total vascularizations. We conclude that the combined therapy of citrate and ascorbate was a significant improvement over citrate treatment alone and almost eradicated corneal ulceration.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

We compared the distribution of HLA-ABC (Class I) and HLA-DR, -DQ, and -DP (Class II) antigens in fresh, nonlyophilized human cornea with that of rehydrated lyophilized epikeratoplasty lenticules. Class I antigens were detected at similar levels in both the control corneas and the epikeratophakia lenticules. Class II antigens, which were limited to cells at the limbus of control corneas, were absent from the epikeratophakia lenticules. Although epikeratophakia lenticules are not necessarily immunogenic, these results clearly demonstrate that they are antigenic and express selected major histocompatibility antigens. In the context of these findings, we discuss the lack of reports of immunologic rejection following epikeratoplasty.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Corneal stromal fibroblasts play an important role in wound healing. Proteins from all three cytoskeletal classes (microfilament, microtubule, and intermediate filament) are involved in the control of various cellular events, such as motility, cell adhesion, shape changes, intracellular transport, and mitosis. By epifluorescent light microscopy, we studied the intracellular distributions of actin (microfilament), tubulin (microtubule), and vimentin (intermediate filament), as well as vinculin (a junctional protein connecting microfilaments to the cell membrane), in cultured corneal fibroblasts. Mutual positional relationships between actin and the other cytoskeletal proteins were investigated by double-labeling. Particular attention was paid to the leading edge of spreading or migrating fibroblasts and to their cell-to-cell contacts.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Persistent donor corneal epithelial defects following penetrating keratoplasty may lead to graft failure. We herein describe a method for providing corneal protection using a temporary suture tarsorrhaphy. This technique is simple and completely reversible, and it allows continued observation and instillation of topical medication during the postoperative period.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Elastofilcon A silcone rubber contact lenses induce less corneal swelling than no lens wear during sleep, and increasing the central thickness and volume of the lens does not influence its overnight performance. We sought to elucidate whether a silicone rubber lens can promote the distribution of atmospheric O2on the cornea through a small interpalpebral opening under closed-eye conditions. Three groups of rabbit eyes comprised 12 eyes wearing Silflex (Dk 79.8 barrer) lenses, 12 with elastofilcon A (Dk 340 barrer) lenses, and 12 without lenses. All eyes were surgically closed overnight; six eyes in each group had a complete lid closure and six eyes had a partial tarsorrhaphy that left a small, central gap ~3 mm in length. When the lids were opened the next morning, the partially closed elastofilcon A eyes showed less corneal swelling (6.2 ± 1.4%) than the partially closed no-lens eyes did (9.6 ± 1.3%) (p<0.01), whereas the partially closed Silflex eyes were significantly more swollen (12.8 ± 2.1%) (p=0.01) than the other two partially closed groups were. The completely closed eyes showed no significant difference in corneal swelling among the groups. These results indicate that small lid gaps during sleep may lead to less corneal swelling when elastofilcon A lenses are used than with no lenses.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Wedge resections have been demonstrated to have significant effects on the curvature of the cornea in the meridian of the resection. This paper describes two complimentary, noninvasive, circumferential wedge keratectomy techniques for the correction of spherical ametropia. Eleven eye bank eyes were studied. Four eyes underwent the circumferential anterior-based wedge (ABW) keratectomy technique in an attempt to induce steepening of the cornea. Seven eyes underwent the circumferential posterior- based wedge (PBW) keratectomy in an attempt to flatten the cornea. The mean steepening of 4.86 ± 1.79 diopters in the ABW group was statistically significant (p<0.01). The mean flattening of 7.47 ± 4.46 diopters in the PBW group was also found to be significant (p<0.01). These techniques are presented as viable alternatives to relaxing incision techniques such as radial keratotomy. Further refinement of the technique and improved technology will make these techniques more predictable and reliable.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Local and systemic tumor necrosis factor (TNF) have been shown to have marked tumorcidal effect on VX2 intraocular tumors. Complete ablation or remission of the experimental ocular tumor was not achieved in doses employed. TNF is a potent immune modulator of acute and chronic inflammation. Local toxic effect of TNF to the eye was severe and occurred only in the presence of tumor. Intravitreal TNF will cause severe necrosis of the normal eye. This toxic effect was not seen when intravitreal TNF was injected into a tumor-bearing eye. Chronic perfusion and low doses of TNF in combination with other antitumor agents may be tried in future studies to avoid local and systemic toxicity.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The ability to successfully transplant human corneal endothelium would offer a significant advance in the treatment of many corneal diseases. To investigate the feasibility of this, we established cultures of endothelial cells derived from neonatal human corneas. Eye bank donor corneas were either enhanced with a suspension of cultured endothelial cells or underwent endothelial cell removal and subsequent replacement with cultured endothelium. Following a 48-h incubation, the corneas were transplanted into the eyes of nonhuman primates. Over a 12-month period, 67% of the corneas with complete endothelial cell replacement thinned and remained clear, with a mean corneal thickness of 0.57 mm. Enhanced corneal buttons demonstrated a significantly lower success rate (35%), with opacified and thickened corneas. Control eyes in which the native endothelium was removed demonstrated advanced corneal edema and vascularization, with a mean corneal thickness in excess of 1 mm. By utilizing established tissue-culture techniques, we have demonstrated that human corneal endothelium, when cultured and subsequently transplanted, retains its in vivo pump function. Although further studies are warranted, these results indicate that transplanted human corneal endothelial cells can function normally and suggest the possibility of endothelial cell replacement for therapeutic purposes.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Scanning electron microscopy was used in a morphometric analysis of the surface cells of the young (1.9–2.4 kg) female albino rabbit. A complete survey of the corneal surface was made (115 micrographs at ×500), and cell area, and longest and shortest dimensions were measured. The cell population, on the basis of electron reflex (light, medium, and dark), was resolved into three overlapping populations of cells. The light cells tended to show the smallest area and the smallest dimensions, whereas the opposite was found for dark reflex cells: Medium reflex cells had intermediate areas and cell dimensions. However, no clear-cut resolution simply by size (small, medium, large) was observed.

ISSN:0277-3740    

出版商:OVID    

年代:1991

数据来源: OVID