摘要:

The Collaborative Corneal Transplantation Studies (CCTS) is a set of two multicenter clinical trials designed to investigate the efficacy of donor-recipient human leukocyte antigen matching and crossmatching. High-risk penetrating keratoplasty patients were enrolled through six clinical centers for either the Antigen Matching Study or the Crossmatch Study. All patients were subject to a common set of examinations, treatments, and evaluation procedures. Standard procedures for the identification of high-risk patients, administration of postoperative medications, and recognition and treatment of immunologic allograft reactions were developed and used successfully. These procedures may serve as guidelines for studies in corneal transplantation. Adoption of these methods by other investigators would facilitate evaluation and comparison of results.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Two donor cornea preservation methods, moist chamber and chondroitin sulfate-containing medium, were prospectively compared clinically. Paired corneas from 11 donors were divided into two groups: moist chamber group (mean preservation time 9.1 h) and Optisol (Chiron Co., Irvine, CA, U.S.A.) group (mean preservation time 70.8 h). They were compared in terms of their clinical course, corneal thickness, and endothelial density. Recipient age, sex, and diseases were matched between the groups. Nine of 11 corneas in the moist chamber group, and 10 in the Optisol group remained clear at 6 months after surgery. Decreases of the endothelial density were 28.4% in the moist chamber group, and 30.1% in the Optisol group at 6 months after surgery. No differences were found in either endothelial density or corneal thickness throughout the observation period. It was shown that the corneoscleral preservation using chondroitin sulfate-containing medium was as useful as the conventional moist chamber preservation. Considering the requirement for longer donor preservation time, corneoscleral preservation should be adopted in areas other than the United States.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Hydrogen peroxide (H2O2) has potent oxidant properties due to the action of free radicals (OH) induced from its degradation. The free radicals specie derived from H2O2are extremely toxic to the corneal endothelium and quickly induce corneal edema. In the present work, in order to ascertain the endothelial cell protection from viscoelastic substances, we have studied experimental corneal endothelial cell damage caused in the rabbit eye after intracameral injection of different H2O2concentrations, with and without previous filling and washing out of two widely used viscoelastic substances from the anterior chamber such as 1% sodium hyaluronate (Healon) and hydroxypropylmethylcellulose (HPMC). We observed a dose-dependent endothelial damage in the controls. The experimental groups protected with Healon or HPMC showed statistically fewer corneal endothelial cell lesions than the control group (ρ <0.001) for all of the concentrations used. Healon showed superior protective properties than HPMC at higher H2O2concentrations (100 mM). However, HPMC was superior with 1 and 10 mM peroxide. From this experimental evidence, we conclude that Healon and HPMC are effective as protectors against the corneal endothelial lesions caused by free radicals. This finding may explain some of the beneficial effects of these viscoelastic substances.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

In severe dry eye syndromes the corneal epithelium is compromised with development of punctate erosions and increased permeability. In the present study the ability of artificial tear solutions to promote recovery of the corneal epithelial barrier was determined by measurement of corneal uptake of 5,6 carboxyfluorescein (CF). Corneas of anesthetized rabbits were exposed to 0.01% benzalkonium for 5 min to increase epithelial permeability. The cornea was then exposed to an artificial tear solution for 1.5 h followed by measurement of CF uptake. During exposure to three commercial isotonic, nonpreserved solutions and a solution preserved with polyquaternium-1, CF uptake decreased significantly but did not return to control. No recovery of the epithelial barrier occurred during exposure of corneas to nonpreserved hypotonic solutions. During exposure to an experimental tear solution with an electrolyte composition similar to human tears, buffered with bicarbonate, CF uptake returned to control levels. Bicarbonate is an essential component of this solution because the same formula buffered with borate or without buffer was ineffective in promoting recovery of the damaged corneal epithelium.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The process of recruitment and screening of volunteers for clinical research studies has not been thoroughly evaluated in the ophthalmic literature. The data for the current report were derived from a double-masked randomized clinical trial designed to evaluate and compare the effective tear level concentrations of three topical ophthalmic medications. Subjects were recruited from the general population and were healthy volunteers on no medications. Tear volume was measured by the Schirmer test with anesthesia; acceptable results were in the range of 10-25 mm/5 min. Study enrollment was limited to 32 subjects per week, with a total sample size goal of 320. The study population, 18-45 years of age, consisted primarily of white male college students. Nine hundred fiftyseven volunteers were recruited. Of the 498 of these subjects that reported for screening (52%), 459 (48%) were actually screened, and 320 (33%) were enrolled. The overall prevalence of an abnormal Schirmer test (<10 or >25 mm/5 min in either eye) in the screened population was 22%. The frequency of decreased tear production (13%) was slightly greater than that of increased tear production (9%). An abnormal Schirmer test was the primary reason for ineligibility. The completion rate for those enrolled was 96%. This type of information is valuable when designing a clinical trial, especially with regard to budgetary, time table, and sample size estimations.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Twelve adult patients with keratoglobus are described. Associated ocular conditions included orbital pseudotumor, vernal keratoconjunctivitis in three patients, chronic marginal blepharitis with chronic eye rubbing, and glaucoma after penetrating keratoplasty surgery. Hydrops occurred in 19 of the 21 eyes with keratoglobus. Surgical procedures to treat keratoglobus included large-diameter lamellar and penetrating keratoplasty, and limbus-to-limbus epikeratoplasty.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

This article describes the histopathology, immunohistochemistry, and varicella zoster virus DNA in situ hybridization of 14 corneal buttons obtained from 14 patients (average age 69.0 years) after perforating keratoplasty (four patients) or surgical enucleation (10 patients) at different times after the clinical onset of herpes zoster ophthalmicus (average 58.7 months). The main histopathologic features were intense stromal vascular scarring (12 patients) and granulomatous reaction to Descemet's membrane (nine patients). Using the peroxidase-antiperoxidase method, varicella zoster virus (VZV) antigen could be detected by immunohistochemistry in two patients within epithelial cells of the cornea and in the limbal episclera during the active phase of herpes zoster ophthalmicus. For in situ hybridization we used the 35Slabeled HindIll A and C fragment of VZV and identified viral DNA in five corneal buttons obtained 1 day to 8 years after the clinical onset of infection. Viral DNA was mainly found in mononuclear cells with eosinophilic intracytoplasmic inclusions within vascular stromal scars, in keratocytes, and in epithelial cells of the cornea. Our results show that VZV DNA is detectable in human cornea even 8 years after the clinical onset of herpes zoster ophthalmicus and may indicate VZV persistence in a latent form in corneal tissue or reactivation of the virus from an endogenous or exogenous source causing a severe and often recurrent keratitis in the progress of herpes zoster ophthalmicus.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

To compare the efficacy of ciprofloxacin hydrochloride ointment with that of ciprofloxacin drops for treatment of experimental ρseudomonas keratitis, rabbit eyes were infected by intrastromal injection of 103colony-forming units (CFU) log-phaseP.aeruginosa. Infected and uninfected eyes were treated with either 0.3% ciprofloxacin ointment applied hourly for 6 h or 0.3% ciprofloxacin drops applied every 15 min for 6 h. Infected eyes treated with the ointment or drop vehicle alone served as placebo controls. Ciprofloxacin ointment significantly reduced the number of viable bacteria (CFU) per cornea more than four logs compared to the placebo control (ρ<0.0001). Ciprofloxacin drops significantly reduced the number of bacteria (CFU) per cornea >7 logs as compared with placebo-treated controls (ρ<0.0001). Ciprofloxacin ointment may be a useful adjunct to conventional topical drops for therapy of bacterial keratitis.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Ophthalmological examination was made for 447 hypercholesterolemic middle-aged Eastern Finnish men participating in the Kuopio Atherosclerosis Prevention Study (KAPS) in order to evaluate the prevalence of corneal arcus, its risk factors, and possible association with atherosclerosis. The degree of atherosclerosis was assessed by ultrasonographic examination of carotid and femoral arteries. Corneal arcus in either eye was observed in 51.4% of the participants. Old age and high LDL cholesterol concentration were associated with the presence of corneal arcus. Corneal arcus had a close relationship with ultrasonographically assessed atherosclerosis.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

In this study we investigated the properties of corneal aldehyde dehydrogenase (ALDH) in keratoconus corneas using various electrophoretic techniques combined with immunochemical and zymographic identification. Normal corneas and other pathologic corneal buttons obtained during keratoplastic surgery were used as a control. A significant (p<0.001) lower enzymatic activity was found in keratoconus epithelial extracts (3.1 ± 2.1 IU/mg protein) compared with normal controls (5.5 ± 2.6 IU/mg protein), whereas no significant differences were observed in the stromal and endothelial extracts. No significant differences were observed for the corneal ALDH thermolability behavior, nor did any marked changes occur in the position of the 54- and 88-kDa species when comparing the pathologic corneas and normal controls. On the other hand, isoelectric focusing analysis showed a different pattern for the pathologic corneas as compared with controls. Moreover, native-polyacrylamide gel electrophoresis analysis showed that normal corneas exhibit three bands, whereas keratoconus and other pathologic corneas only show two bands. The shift from the three-band pattern to the two-band pattern could be reproduced in vitro using reducing agents, such as glutathione

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID