ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To measure endothelial cell and keratocyte densities in transplanted corneas and the changes in these densities with time.Methods.The endothelia of 500 consecutive penetrating corneal transplants were studied longitudinally by specular microscopy for 10 to 20 years. The keratocytes of 36 corneal transplants that varied in postoperative times from 1 month to 20 years were studied cross-sectionally by clinical confocal microscopy. The keratocytes of five transplanted corneas were studied longitudinally by confocal microscopy at 1 day, 1 week, and 1 month postkeratoplasty.Results.Endothelial cell density decreased progressively at an accelerated rate for 20 years after transplantation, with concurrent increases in the coefficient of variation of cell area and corneal thickness and decreases in the percentage of hexagonal cells. Grafts with insufficient endothelial cells developed late endothelial failure, which was the primary cause of graft failure after the first 5 postoperative years. The grafts with late endothelial failure did not lose endothelial cells faster than grafts that did not fail, but instead had fewer cells immediately after transplantation, diminishing to a critically low cell density earlier. The keratocyte density was also decreased in transplanted corneas. Keratocytes became “activated” during the first week after keratoplasty and in grafts with late endothelial failure.Conclusion.It should be possible to prevent or delay late endothelial failure, the primary cause of graft failure, by increasing the number of endothelial cells on transplanted corneas. The status of the keratocytes appears to affect corneal transparency and, thus, visual quality in the grafted eye.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.This study was designed to evaluate the effect of anterior stromal puncture to treat patients with symptomatic bullous keratopathy.Methods.Fourteen patients with bullous keratopathy who had decreased vision and were or were not awaiting penetrating keratoplasty were evaluated before and 1, 4, 12, and 24 weeks after anterior stromal punctures with a 25-gauge needle. The patients were questioned about pain intensity, foreign-body sensation, and photophobia. Biomicroscopy, esthesiometry, and pachymetry results were evaluated. The results before and after the punctures were compared using the McNemar test, Friedman test, and multiple comparison tests.Results.The comparisons among before and 1, 4, and 12 weeks after the anterior stromal puncture of pain (p= 0.00000556), photophobia (p= 0.0252), foreign-body sensation (p= 0.0000743), and esthesiometry (p= 0.0243) showed significant statistical differences in terms of decreasing symptoms and corneal sensitivity. The average pachymetry did not show statistical difference among before and 1, 4, 12, and 24 weeks after the procedure (p= 0.956). We did not find important differences in terms of corneal neovascularization.Conclusion.Anterior stromal puncture is an effective, simple, and low-cost alternative for treating patients with symptomatic bullous keratopathy.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.We report our experience of anterior stromal puncture (ASP) in symptomatic chronic corneal edema patients awaiting penetrating keratoplasty (PK) and hypothesize the mechanism of action of ASP in bullous keratopathy (BK).Methods.We reviewed the medical records of 28 patients with BK who underwent ASP between November 1996 and September 1999 with at least 1 month of follow-up. In all these patients, approximately 200 punctures were given with a bent 26-gauge needle sparing the peripheral cornea. Patients were examined on days 1 and 7, 1 month, and every 3 months after the procedure. The symptoms, corneal findings, and visual acuity of the patients at last follow-up were noted and compared with the preprocedure findings. For 11 patients who underwent PK, histopathologic study of corneal buttons was performed and a clinicopathologic correlation was attempted.Results.Of the 28 patients, there were 15 men and 13 women with a mean age of 61.1 years. The clinical diagnosis was pseudophakic BK in 11 (39.3%), aphakic BK in 11 (39.3%), Fuchs' dystrophy in 4 (14.3%), failed graft in 1 (3.6%), and chronic corneal edema of unknown etiology in 1 (3.6%). The follow-up ranged from 1 to 33 months with a mean of 9.5 ± 7.5 months. Symptomatic relief was noted in all. Twenty patients (71.4%) had complete relief, whereas eight patients (28.6%) experienced mild symptoms such as tearing and occasional pain. Visual acuity improved in 7 patients (25%), decreased in 12 (42.8%), and remained the same in 9 (32.4%). Objective evidence of scarring after ASP was noted in all patients. Complete regression of epithelial bullae and epithelial edema was found in 10 (35.7%) and partial regression in 18 (62.25%) patients. There was no progression or appearance of new blood vessels except in one patient (3.6%). Histologically, puncture marks and superficial stromal scarring were noted in all corneal buttons. Adhesion of epithelium with varying degrees of subepithelial fibrosis was seen in six, whereas in the remaining five buttons, there was complete denudation of the epithelium. Vascularization was seen in five and inflammation in two buttons. Clinicopathologic correlation revealed that symptomatic patients had persistent edema and loose adhesion of the epithelium to the stroma, resulting in detachment.Conclusions.ASP is a simple, safe, and cost-effective outpatient procedure for symptomatic relief in patients with BK. The possibility of decreased visual acuity after the procedure should be explained to all patients. Although ASP promoted subepithelial fibrosis in all cases, its subsequent adhesion is variable and probably has clinical relevance. Further studies could be directed toward identifying specific mediators that promote epithelial–stromal interaction and firm anchoring of epithelium to the underlying stroma.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.We evaluated the clinical results of nonsimultaneous penetrating keratoplasty, cataract extraction, and intraocular lens (IOL) implantation (two-stage surgery) for combined corneal disease and cataract.Methods.Twenty-six eyes of 24 patients with an average age of 46 years who underwent two-stage surgery were studied retrospectively. Variables included visual acuity, refractive status, specular microscopy before and after IOL implantation (6 months), and the occurrence of graft failure. Astigmatism was corrected by suture removal and relaxing incision. The mean follow-up after IOL placement was 16 months.Results.Unaided visual acuity was 20/100 or better in 22 (83%) eyes after the second procedure. Twenty-one (81%) eyes had an aided visual acuity of at least 20/40. The mean refractive and absolute errors were −1.49 ± 1.39 diopters (D) and 1.55 ± 1.30 D, respectively. The mean keratometric and refractive cylinders were 3.50 D and 2.26 D, respectively. Nineteen (73%) eyes had a spherical equivalent refraction within 2 D of emmetropia. Anisometropia (≥3 D) occurred in four (15%) eyes. The endothelial cell density, the coefficient of variation, and the percentage of hexagonal cells documented by specular microscopy were not significantly different before and after IOL implantation. Complications included three rejections, two cases of herpetic recurrence, and one late decompensation. Two graft failures (8%) occurred after secondary surgery.Conclusion.The two-stage surgery is a safe and effective modality.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To assess the utility of donor corneoscleral rim cultures.Methods.A retrospective review of the culture results of 774 corneoscleral rims that remained after trephination of corneas for transplantation into patients at our academic medical center between January 1992 and November 1997.Results.Forty-one (5.3%) corneoscleral rim cultures yielded microorganisms, mostly coagulase-negative staphylococci. Two patients developed endophthalmitis (one withStaphylococcus aureusand one withPseudomonas aeruginosa) within 3 months after transplantation; each had a negative corneoscleral rim culture and neither patient's infection was temporally related to the transplant procedure.Conclusions.Preoperative donor corneoscleral rim cultures are unreliable predictors of endophthalmitis complicating corneal transplantation and, therefore, are not useful in the clinical management of patients having corneal transplants. Moreover, the discrepancy between the results of corneoscleral rim cultures and subsequent endophthalmitis renders them invalid as a quality assurance procedure. Instead, for patients with suspected endophthalmitis after corneal transplantation, we recommend that corneal surgeons select antimicrobial therapy based on current guidelines and the results of directed sampling. Furthermore, eye banks should prospectively track recipients who develop clinical endophthalmitis, immediately notify the corneal surgeon who transplanted the matched cornea of that used for the index case, and, in selected situations, attempt to identify a possible source of contamination.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To study the outcome of corneal transplants performed with cryopreserved tissue.Methods.Maisonneuve-Rosemont Hospital medical records of all corneal transplantations performed with cryopreserved tissue by one surgeon (M.L.F.) between March 1978 and April 1991 were reviewed. The Kaufman–Capella cryopreservation technique was used. Corneas were cryopreserved for periods of 3 days to 16.8 years (mean, 4.6 years) before transplantation.Results.We report a mean follow-up of 54 months (range, 2.8–151.3 months). Survival analysis showed the probability of a clear graft to be 76% at 1 year and 73.2% at 2 years. At the time of the last visit, visual acuity was 20/40 or better in 61 eyes (49.2%). The mean postoperative pachometry was 0.58 mm (range, 0.50–0.75 mm). Specular microscopy performed in 57 eyes showed a mean endothelial cell count of 938 cells/mm255.1 months (range, 2.9–151.3 months) after surgery. For comparison purposes, the outcome of a subgroup of cryopreserved (n= 33) and noncryopreserved (n= 26) corneas transplanted by the same surgeon between April 1986 and April 1990 was studied.Conclusion.Despite an increase in the primary failure rate and higher initial endothelial cell loss, cryopreserved transplants are viable. Although we do not recommend cryopreservation of corneas for elective surgery, we consider that cryopreserved corneas can be very useful in emergency situations when tissue availability is a problem.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To report the acute effects of laser in situ keratomileusis (LASIK) on the corneal endothelium.Methods.Twenty eyes of 10 consecutive patients (mean age, 38.1 ± 10.84 years) underwent bilateral simultaneous LASIK for myopic astigmatism (spherical equivalent ranging from −1.75 to −7.13 diopters) without any complications. Each eye was evaluated by slit-lamp biomicroscopy and noncontact specular microscopy preoperatively, within 15 minutes after LASIK and 1 day after surgery. Specular microscopy images were then analyzed to calculate endothelial cell density (ECD), coefficient of variation (CV) of cell size, and percentage of hexagonal cells.Results.All corneas demonstrated marked alterations in endothelial cell morphology by slit-lamp biomicroscopy within 15 minutes after surgery that resolved by the first postoperative day. Central corneal endothelial analysis by noncontact specular microscopy confirmed pleomorphism with definite loss of hexagonality. Mean ECD was calculated to be 2,816.3 ± 286.02 cells/mm2preoperatively, 2,750.85 ± 327.95 cells/mm2on day 0 (p= 0.395), and 2,810.55 ± 218.48 cells/mm2on day 1 (p= 0.461). Mean CV was 32.65 ± 7.29 preoperatively, 34.4 ± 6.19 on day 0 (p= 0.412), and 30.9 ± 5.54 on day 1 (p= 0.067). Mean percentage of hexagonal cells was 63.35 ± 10.76 preoperatively, 47.55 ± 9.69 on day 0 (p= 0.000009), and 60 ± 9.3 on day 1 (p= 0.00003).Conclusion.Qualitative and quantitative changes in endothelial cell morphology (i.e., decreased endothelial cell hexagonality) demonstrate that LASIK does induce an acute effect on the corneal endothelium that may represent transient endothelial cell edema.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To identify changing trends in penetrating keratoplasties (PKs) performed at the Hotel-Dieu Hospital in Paris between January 1980 and December 1999 and to explain the reasons for the changes.Methods.We retrospectively reviewed 3,736 of the 3,836 PKs performed between January 1, 1980, and December 31, 1999, and classified them into diagnostic categories.Results.The most common indications for PK were keratoconus (28.8%), herpetic infections (10.9%), graft failures (9.9%), aphakic and pseudophakic corneal edema (9.9%), Fuchs' endothelial dystrophy (9.4%), and nonherpetic leucoma (7.7%). Other indications represented 23.4% of the cases. The incidence of aphakic and pseudophakic corneal edema progressively increased between 1980 and 1991, became the most frequent indication in 1991 (21.4%), and then progressively decreased. The annual number of PKs increased between 1980 and 1986, decreased between 1987 and 1997, and increased again after September 1997. The decrease was caused by both a shortage of corneal buttons, and, in 1987, the fear of transmitting diseases through corneal transplantation, particularly human immunodeficiency virus. Beginning in 1992, decreases were also associated with stringent governmental regulations of eye bank tissue.Conclusion.Changes in the incidence and management of corneal disorders were the primary factors leading to modifications of grafting until 1987. After 1987, corneal button shortage probably corresponded to the acquired immune deficiency syndrome epidemic. Governmental regulations of eye banking led to a severe corneal button shortage between 1992 and 1997. Despite an increase in the number of PKs performed after 1997, corneal buttons are still preferentially allocated to patients in whom there is a high probability of graft success.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To evaluate the utility of Etest in choosing the appropriate treatment of fungal keratitis.Methods.Etest was used to determine the drug sensitivities of isolates from the eyes of three patients with fungal keratitis, and the clinical outcomes of treatment with selected drugs were evaluated.Results.In all cases, drug sensitivity demonstrated by Etest accorded with clinical efficacy of the drugs.Conclusion.The results in these cases suggest that evaluating drug sensitivities with Etest is an efficient means of selecting optimal pharmacotherapy for fungal keratitis.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID