摘要:

Purpose.To review the development and application of corneal topography in refractive surgery.Methods.Review of the literature and discussion of recent developments in corneal topography and wavefront technology.Results.Analysis of corneal topography provides critical information for the preoperative examination of patients before refractive surgery and for the evaluation and treatment of patients with complications after surgery.Conclusions.Corneal topography will continue to be a critical diagnostic modality for refractive surgery. Even with the advent of wavefront analysis designed to detect refractive error and aberrations of the eye, it will be necessary to have detailed corneal topographic information to understand the contribution the cornea makes to vision so that custom alteration of that surface can be used to optimize vision. This will be true of the normal eye, but it will be of special importance in eyes with abnormalities that were induced by corneal surgery.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To report the outcome of ipsilateral rotational autokeratoplasty performed for nonprogressive central corneal opacities.Methods.Medical records of 27 patients who underwent ipsilateral rotational autokeratoplasty between June 1995 and December 1998 were retrospectively reviewed. The etiology of corneal opacity, preoperative visual acuity, and size of the trephine used was noted. Any intraoperative and early and late postoperative complications were noted in all patients. The final outcome, visual acuity, and astigmatism at final correction were analyzed.Results.The main etiology of corneal opacity was trauma (44.4%), followed by resolved keratitis (29.6%). The size of the graft ranged from 6.5 to 9 mm. Fifteen patients underwent autokeratoplasty alone; additional procedures were combined in the remaining 12. Wound leak was the most common postoperative complication, which was seen in seven patients. The mean follow-up was 12.11 months (SD = 11.95 months). Five patients (18.5%) were lost to follow-up. Of the remaining 22, 19 (86.36%) had clear grafts and 3 (13.6%) had failed grafts. The mean astigmatism at final correction was 4.25 diopters cylinder (SD = 2.72). Final visual acuity of 20/80 or better was obtained in 13 cases (59.09%).Conclusions.Contrary to common belief, ipsilateral rotational autokeratoplasty is a safe and effective surgical procedure. It can be considered as an alternative procedure to penetrating keratoplasty in a scenario in which tissue scarcity exists, as well as in cases that have a high risk of developing immunologic allograft rejection. Further prospective studies with preoperative specular microscopy and postoperative corneal topography will provide greater insight into the usefulness of this procedure.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Objective.To report our experience in treatment and outcome ofNocardiakeratitis.Methods.Medical and microbiology records of seven cases of culture-provenNocardiakeratitis seen between January 1997 and March 1999 were reviewed retrospectively. In all patients, corneal scrapings were obtained for direct microscopic evaluation and culture. Drug sensitivity was determined by the Kirby–Bauer disk-diffusion method. The minimum inhibitory concentration of ciprofloxacin and amikacin for these isolates was determined by agar dilution method. Response to medical therapy and the end result were analyzed.Results.By the in vitro Kirby–Bauer disk-diffusion techniques, all isolates were sensitive to amikacin; six of these isolates were sensitive to gentamicin and four were sensitive to ciprofloxacin. The minimum inhibitory concentration (MIC) of amikacin for all isolates by the agar-dilution technique was well below the MIC breakpoint forNocardiaresistance, whereas the MIC of ciprofloxacin was above the MIC breakpoint forNocardiaresistance. All patients responded to medical therapy. The corneal infection resolved in three patients after treatment with ciprofloxacin, in one patient after fortified gentamicin, and in three patients after fortified amikacin. Outcome details were available for six patients. There was good visual recovery in four patients, with visual acuity of 20/25 or better in three. The cornea of two patients developed nonvascularized scars, and in four patients in whom the infiltrates were peripheral, vascularization was seen.Conclusions.Although patients ofNocardiakeratitis may respond to other antibiotics, amikacin appears to be a drug of choice. In this small series, when appropriate therapy was initiated,Nocardiakeratitis resolved promptly with good visual recovery.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To determine the levels ofAcinetobacterspecies associated with normal soft contact lens wear and to determine whetherAcinetobacterspecies are involved in adverse reactions that occur during contact lens wear.Methods.Patients wore soft contact lenses on an extended-wear basis. The bacteria on lenses and ocular swabs during asymptomatic and symptomatic lens wear were identified using standard microbiologic methods.Results.Acinetobacterspecies were isolated and identified from 16 (13%) of 126 patient samples. Greater numbers ofAcinetobacterspecies were isolated from lenses of patients experiencing adverse responses than from asymptomatic patients.Acinetobacterspecies were isolated from patients experiencing symptomatic adverse responses in 4 (13%) of 32 cases.Conclusion.It appeared thatAcinetobacterspecies colonized the eye of extended contact lens wearers at a time when the normal functioning of the eye was compromised by contact lens wear. WhenAcinetobacterspecies were in high numbers on a contact lens, an adverse response occurred. This may implicateAcinetobacterspecies as a contributing factor to adverse responses associated with contact lens wear.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Microbially contaminated contact lens cases are a predisposing risk factor forAcanthamoebakeratitis. Several findings have shown that microwave irradiation kills the six Food and Drug Administration test challenge microorganisms. We aimed to determine what effect microwave irradiation has onAcanthamoebatrophozoites and cysts.Methods.Different types of contact lens cases were contaminated with trophozoites and cysts of three differentAcanthamoebaspecies (A. comandoni, A. castellanii, A. hatchetti) and were exposed to microwave irradiation for 3, 5, and 8 minutes, respectively.Results.Trophozoites, as well as cysts of the differentAcanthamoebastrains, were effectively killed, even by only 3 minutes of microwave irradiation, and there were no negative effects of irradiation on the contact lens cases themselves.Conclusion.We demonstrate that microwave treatment is a very effective, easy, and cheap method to keep contact lens cases free ofAcanthamoeba,thus considerably reducing the risk of anAcanthamoebakeratitis.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To determine the benefit of bilateral penetrating keratoplasty with regard to binocular vision.Methods.We compared patients who underwent corneal transplantation bilaterally with patients who had successful corneal transplantation in one eye and corneal disease in the other eye. Specifically, changes in fusion, stereopsis, and binocular vision function were analyzed. A questionnaire regarding performance of daily tasks was given.Results.Patients with bilateral keratoplasty performed better in all the analyzed functions. Fusion was achieved by 81.25% in the unilateral group versus 100% in the bilateral group (p= 0.15). Stereopsis was present more in the bilateral group (100% vs. 62.5%,p= 0.008) and the quantity of stereopsis was significantly better in the bilateral group (121 seconds of arc vs. 1,284 seconds of arc,p= 0.014). 88.8% of the patients subjectively improved in daily activities after second eye surgery.Conclusion.There are objective and subjective improvements after bilateral penetrating keratoplasty.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Pennsylvania Act 102 implemented in March 1995 required all acute care hospitals in Pennsylvania to routinely refer all deaths to the Organ Procurement Organization for determination of suitability for organ/tissue donation. This study analyzed the effect of the law on eye donation.Methods.Retrospective analysis of the total number of referrals and the actual number of eye donations from 62 hospitals in Pennsylvania to the Lions Eye Bank of Delaware Valley was performed for the years 1993 to 1998. Information gathered included donor's age, gender, race, cause of death, referring institution, and result of referral.Results.From 1993 to 1998, the total numbers of referrals were 988, 1,647, 8,101, 21,123, 21,783, and 22,987, and the numbers of donors were 570, 574, 660, 644, 594, and 568, respectively. The increase in the number of donors after implementation of the law was not commensurate with the number of referrals. This was caused by a disproportionate increase in the number of referrals older than 70 years of age (from a mean of 33% to 52%), which exceeded the donor age limit of 69 years, and also to a lower family consent rate (from a mean of 48% to 24%).Conclusions.Well-designed state legislation with proper implementation greatly increased hospital referrals for eye donation. However, there was only a small increase in the number of eye donors because many of the referrals were beyond the acceptable upper age limit for eye donation. A small increase in the donor age limit would increase the number of eye donations without having to expand the potential donor pool. Education of the public may help to improve the family consent rate.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To determine the feasibility of optical coherence tomography (OCT) measurement of overnight corneal swelling and de-swelling and, specifically, to examine overnight changes in the corneal epithelium and recovery during the day.Methods.Ten healthy volunteers were recruited. Corneal OCT imaging was performed at 10:00 PM (baseline), 8:30 AM, and every 2 hours thereafter until 4:30 PM. Either the right or left eye was taped shut (using a gauze pad and surgical tape) until the 8:30 AM session of the next day. Measurements were made along a 1-mm strip centered on the visual axis.Results.At baseline, there were no differences in corneal or epithelial thickness between control and experimental eyes (allp> 0.05). Immediately after patch removal, corneal and epithelial thicknesses of patched eyes were higher than the baseline (allp< 0.05). In patched eyes, the cornea and epithelium swelled 5.5% and 8.1% overnight, respectively (p> 0.05). Two hours later, the epithelial thickness of the experimental eyes recovered to baseline level (p> 0.05), but corneal thickness did not reach to baseline level until 4 hours after patch removal. For control eyes, there were no differences compared with baseline (allp> 0.05).Conclusion.Both cornea and corneal epithelium experience proportionately similar amounts of overnight swelling. Recovery of overnight swelling may be slower for the cornea than for the epithelium. OCT provides valuable information about anterior segment morphometry.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To quantify the tear spreading velocity and stabilization time after blinks in healthy patients.Methods.Video recordings (magnification, ×130) were made of the movements of naturally occurring particles in the tear film while patients blinked naturally. After each blink, tear spreading velocity was computed every 40 milliseconds from particle displacements determined from a frame-by-frame analysis of the records.Results.After a blink, tears moved rapidly upward over the cornea. Forty milliseconds after passage of the lid, the velocity was 7.34 ± 2.73 mm/s (mean ± standard deviation,n= 20). The time to tear stabilization (i.e., zero velocity) was 1.05 ± 0.30 seconds. The decay of spreading velocity with time was well described by a logarithmic function for all individual patient data (R2range, 0.88–0.99;n= 20). We have shown that initial velocity and stabilization time are independent descriptors of tear spreading. Meibomian gland expression markedly reduced initial velocity leaving a normal stabilization time, whereas inhalation of an irritant reduced stabilization time leaving a normal initial velocity. In a patient with Sjögren syndrome, punctal plugs rapidly restored initial velocity and stabilization time from near zero values to normal values.Conclusion.We provide normal values for two descriptors of tear spreading, namely initial velocity and time to stabilization. These values can be modified by manipulations that alter tear constituents. Consequently, these descriptors may provide a basis for quantitative, noninvasive tear assessment.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Patients with severe limbal deficiencies are unable to maintain a stable corneal surface. If sheets of cultured allogeneic corneal epithelium could be prepared from eye banked corneal limbal rings, which are normally discarded after keratoplasty, the sheets may be beneficial for grafting onto patients with limbal stem cell deficiencies.Method.Biopsies of limbal tissue (2–3 mm2) removed from organ-cultured corneal limbal rings or from fresh whole globes were either trypsinized or set up as explants to assess their potential for corneal epithelial cell production.Results.Several biopsies were taken from each of 21 organ-cultured limbal rings and 10 fresh cadaveric globes. Cultures were generated from every cadaveric eye (10/10), although not all biopsies from the same eye gave rise to cultures. Confluent sheets of cultured cells were also produced successfully from limbal rings that had been in organ culture for up to 25 days, but the success rate from limbal ring material was variable (14/21). An analysis of parameters associated with each limbal ring was carried out in an attempt to identify the reasons for the different efficiencies of epithelial production. No obvious single parameter correlation was detected, although there was a trend to poorer efficiency with increased donor age.Conclusions.Confluent sheets of cultured corneal epithelial cells, suitable for grafting, can be produced from limbal tissue taken from eye bank organ-cultured corneas, although it takes longer, on average, to reach confluence (17–21 days) than an equivalent sample from a fresh eye (9–12 days).

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID