摘要:

PurposeTo review from a historical perspective the recent epidemic ofAcanthamoebakeratitis and its association with the use of contact lenses and to provide a summary of recent techniques that have allowed earlier diagnosis and treatment.MethodsThe authors reviewed available literature onAcanthamoebakeratitis from 1973 to the present, with emphasis on the history of the epidemic and its association with contact lenses, identification of risk factors, preventive measures, and current diagnostic techniques. We also estimated the annual incidence ofAcanthamoebakeratitis during 1985 through 1987 from available data.ResultsBefore the popularization of soft-contact-lens wear,Acanthamoebakeratitis was extremely rare; however, an epidemic began in the early 1980s, and the number of cases increased dramatically beginning in 1984. By 1985, the association of this infection with the use of contact lenses was firmly established, and in 1987, the infection was shown to occur more commonly among men, as well as in contact-lens wearers who failed to disinfect their lenses as frequently as recommended, swam while wearing lenses, or used homemade instead of commercially prepared saline solution. Adoption of “disposable” contact lenses in the late 1980s did not decrease the risk ofAcanthamoebakeratitis, and concerns remain regarding the effectiveness of some contact-lens disinfectants; however, recent advances in diagnosis and treatment have improved the prognosis. The annual incidence during 1985 through 1987 was conservatively estimated at 1.65 to 2.01 cases per million contact-lens wearers. It is unclear whether the incidence is declining.ConclusionAcanthamoebakeratitis has now been recognized worldwide, and there are clear associations of this infection with improper contact-lens hygiene, particularly contact with water. Recent methods allow earlier diagnosis and thus improved outcomes. The epidemic provides a valuable lesson on how a new technology can be associated with unforeseen complications and exemplifies how rapid dissemination of epidemiologic information can aid in controlling an emergent epidemic.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo review the available treatment modalities forAcanthamoebakeratitis and to assess the most effective regimens.MethodsThe efficacy of therapeutic modalities and chemotherapeutic agents used in the treatment ofAcanthamoebakeratitis was reviewed. Potential synergistic or additive drug interactions were documented both in vitro and in vivo.ResultsEarly diagnosis ofAcanthamoebakeratitis plays a crucial role in successful medical treatment. The cationic antiseptic agents, chlorhexidine and polyhexamethylene biguanide (PHMB) have the lowest minimal amoebicidal concentrations. Synergistic effects are seen when used with pentamidine, and additive effects are seen with propamidine or neomycin. Penetrating keratoplasty should be deferred if at all possible until a medical cure has been achieved.ConclusionEarly diagnosis and wide epithelial debridement are important elements in the successful treatment ofAcanthamoebakeratitis. Recommended therapy would include the cationic antiseptic agents, chlorhexidine or PHMB in combination with propamidine isethionate and neomycin as part of triple therapy. Surgical intervention should be avoided until a medical cure has been achieved.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo present the clinical profile, laboratory results, and outcome of treatment in 16 patients withNocardiakeratitis.MethodsA retrospective review of 16 culture-proven cases ofNocardiakeratitis was done. Clinical and microbiologic data were analyzed.ResultsNocardiaconstituted 1.7% of laboratory-confirmed bacterial keratitis and was seen predominantly in male subjects (13 of 16) with a mean age of 39.1 years. Although the predisposing factor was unknown in the majority, a definite history of trauma was present in four (25%) cases. Patchy stromal infiltrates were seen in 12 patients. Wreath pattern of infiltrates (six of 16) and hypopyon (nine of 16) were notable features.Nocardiawas detectable in corneal scrapings of 10 patients with Gram stain and all patients with 1% acid-fast preparation (six of six).Nocardia asteroideswas the causative agent in all except one (N. caviae). All isolates were sensitive to gentamicin; however, topical 30% sulfacetamide was the preferred drug for treatment. Favorable outcome (healed scar) was achieved in 11.ConclusionAlthoughNocardiakeratitis is a rare condition, a high index of clinical suspicion should be kept in agricultural workers or in patients with trauma who have patchy stromal infiltrates. Sulfonamides are the initial drug of choice, and gentamicin could be an effective alternative. If recognized early,Nocardiakeratitis responds to medical treatment with good visual recovery.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo determine the effect of successful pterygium surgery on astigmatism and other corneal topographic indices.MethodsPreoperative and postoperative refraction and corneal-topography analysis were performed on 16 consecutive eyes of 12 patients who underwent successful pterygium surgery, with statistical comparison of the pre- and postoperative visual acuity, refractive astigmatism, topographic astigmatism, Surface-Regularity Index, and Surface-Asymmetry Index.ResultsSuccessful pterygium surgery caused statistically significant improvements in visual acuity, refractive and topographic astigmatism, the Surface-Regularity Index, and the surface asymmetry index.ConclusionCorneal-topography analysis is an important component of the evaluation of patients with pterygium, revealing significant abnormalities that are improved by successful removal of the pterygium.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeBefore invasion of the visual axis, pterygia typically induce with-the-rule astigmatism, which can be visually significant. In this study, we attempted to assess the quantitative relation between pterygium size and induced corneal astigmatism using corneal topography and digital imaging.MethodsThirty-three eyes of 25 patients with primary pterygia were evaluated using corneal topography (TMS), slit-lamp photography, and digital imaging to correlate parameters of pterygium size with induced corneal astigmatism at the 3- and 6-mm optical zones.ResultsPterygia induce asymmetric with-the-rule astigmatism. Lesions extending >45% of the corneal radius or within 3.2 mm of the visual axis produce increasing degrees of induced astigmatism.ConclusionOnce pterygia reach a critical size, they induce visually significant central with-the-rule astigmatic changes that may not be apparent by subjective refraction. This finding helps to identify those patients who may benefit from surgical intervention.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo describe a group of patients with limbal stem cell (SC) deficiency without prior diagnosis of a specific disease entity known to be causative of SC deficiency.MethodsWe performed a retrospective review of the records of all patients with ocular surface disease seen at the University of Minnesota between 1987 and 1996. Patients were categorized according to origin of limbal deficiency. Patients who did not have a specific diagnosis previously described as being causative of limbal deficiency were analyzed. Risk factors, clinical findings, and sequelae were evaluated.ResultsFourteen eyes of 12 patients with SC deficiency not caused by a known diagnosis were described. All eyes had prior ocular surgery involving the corneoscleral limbus. Eleven eyes had been receiving long-term topical medications, and all eyes had concurrent external disease such as pterygium, keratoconjunctivitis sicca, rosacea, herpes simplex virus keratitis, or aphakic or pseudophakic corneal edema. All eyes had superior quadrants affected, corresponding to areas of prior limbal surgery. Sequelae of disease included corneal scarring and neovascularization, with seven eyes having visual acuity of 20/150 or worse.ConclusionBecause the epitheliopathy started peripherally and extended centrally in all patients, we believe it represents an SC deficiency. The fact that all patients were affected superiorly, at sites of a prior limbal surgical incision, points to surgical trauma to the SC as the likely major etiologic factor for the deficiency. The surgical trauma to the limbal SC probably made these cells more susceptible to damage from other external disease influences and toxicity from long-term topical medications. Because the SC deficiency is the result of prior ocular surgery and long-term topical medications, we propose the term “iatrogenic limbal stem cell deficiency.”

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo determine which subjective assessments and objective tests have clinical utility as diagnostic tools in ocular irritation associated with Sjögren's syndrome—related aqueous tear deficiency (ATD), non-Sjögren ATD, inflammatory meibomian gland disease (MGD) associated with rosacea, and atrophic MGD.MethodsForty adults with ocular irritation and 10 with normal ocular surfaces were enrolled in a nonrandomized, nonblinded clinical trial. Symptoms were evaluated. Tests included biomicroscopy; evaluation of tear-film integrity, production, and clearance; fluorescein and rose bengal staining; and serum autoantibody screening.ResultsSymptoms were similar among groups and most severe in the Sjögren's group. Fluorescein tear break-up time was significantly faster in the ATD and MGD groups than that in controls. Schirmer scores were significantly lower in the ATD group than those in MGD and control groups. Tear clearance was delayed in the ATD and atrophic MGD groups. Xeroscope grid distortion was noted only with ATD. The Sjögren's group had greater loss of nasolacrimal reflex, slower fluorescein clearance, and greater ocular-surface fluorescein and rose bengal staining than did the others. More MGD subjects had meibomian gland orifice metaplasia and acinar dropout than did those with Sjögren-related ATD and controls. Schirmer scores correlated inversely with rose bengal staining, corneal fluorescein staining, and grid distortion. Rose bengal staining correlated with grid distortion and loss of nasal—lacrimal reflex, but not with MGD.ConclusionSubjective assessments and objective diagnostic tests have clinical utility as diagnostic tools in tear-film disorders. ATD is correlated with ocular-surface disease. An algorithm summarizing the diagnostic utility of these tests is included.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeClinical research addressing the issue of donor globe decontamination is yet to establish convincing data for the optimal choice of an antimicrobial agent.MethodsIn a donor-globe decontamination study, the antimicrobial effectiveness of a fluoroquinolone antibiotic (ciprofloxacin, 0.3%) was evaluated for the first time and compared with povidone—iodine (P-I, 5%) and gentamicin (0.3%).ResultsCiprofloxacin and gentamicin were found to be less effective than P-I (p< 0.05) in converting culture-positive donor globes to culture negative. In eliminating coagulase-negative staphylococci that predominated the bacterial spectrum, again P-I scored better than ciprofloxacin (p= 0.003) and gentamicin (p= 0.006). Overall, P-I performed better than the other two in the 3-min decontamination procedure. Decontamination was carried out with the same agent for 15 min to assess the effect of duration of decontamination on the antimicrobial activity of P-I. With time, there was no significant increase in the antimicrobial efficacy of the agent except forCorynebacteriumspecies.ConclusionP-I continues to be the preferred agent for decontaminating donor globes. Whereas a contact of 3-min duration between P-I and donor globe remains satisfactory in decontamination procedures, corneal tolerance of this procedure needs investigation.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeCorneas are usually stored for a maximum of ∼30 days in European cornea banks. Although attempts are being made to prolong culture periods, data on their success are extremely limited to date. The following study was carried out to describe the capacities and limits of the established system.MethodsThirty-seven human corneas were stored for less than equal to12 weeks under standard eye bank conditions [modified minimal essential medium (MEM), 31°C, closed system]. Twenty-one fresh human corneas served as control. Both the adenylate nucleotides and the glucose and lactate concentrations were measured in the tissue (all cellular layers) by using the bioluminescence technique. The endothelial-cell densities also were determined.ResultsEndothelial-cell densities decreased from 2,963.4 ± 58.7 cells/mm2(fresh) to 2,649 cell/mm2after 4 weeks and to 2,087 cells/mm2after 6 weeks. Storage for periods >6 weeks led to total endothelial necrosis. Biochemical studies showed improving values during the first 4 weeks and acceptable conditions for less than equal to6 weeks.ConclusionFrom these data, we conclude that long-term organ culture in a closed system is limited to ∼6 weeks and thereby confirm the clinical results of Früh and Böhnke.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo report a surgical technique for the removal of limbal dermoids.MethodsWe propose a method of deep excision and lamellar keratoplasty for limbal dermoid removal.ResultsThis technique achieves near-normal postoperative appearance and function in patients with limbal dermoids.ConclusionThis method appears to offer an effective means of limbal dermoid removal.

ISSN:0277-3740    

出版商:OVID    

年代:1998

数据来源: OVID