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Biomedical subjects

Kirk R Wilhelmus

Publications and source records attributed to Kirk R Wilhelmus.

At least 19 recordsLinked to original sources
PubMed2006

Ecologic effects on eye banking.

PURPOSE: To examine the climatic conditions at corneal donation for microbial categories of postkeratoplasty endophthalmitis that have been reported to a national surveillance registry. DESIGN: Retrospective case-control study. METHODS: Local weather information on the date of donor corneal procurement was tabulated for reported cases of endophthalmitis after penetrating keratoplasty and then compared between candidal endophthalmitis and postsurgical endophthalmitis that yielded bacteria or no microorganisms or that were not cultured. RESULTS: Compared with other postkeratoplasty endophthalmitis, candidal endophthalmitis after corneal transplantation occurred significantly (P < .001) more often when outdoor afternoon temperatures exceeded 75 F at the source eye bank than on cooler days. CONCLUSION: Higher exterior temperatures at donation may be associated with an increased relative risk of candidal transmission by keratoplasty, but a chain of causation that links the donor's environment to the recipient's infection remains to be elucidated.

Body Temperature↗
PubMed2006

Adult-onset syphilitic stromal keratitis.

PURPOSE: To characterize the clinical features and therapeutic outcome of stromal keratitis associated with syphilis in adults. DESIGN: Observational case series. METHODS: We examined the clinical and laboratory records at a single center of individuals with active stromal keratitis who had serological evidence of syphilis by a treponemal specific test. RESULTS: Five patients, 36 to 81 years of age, developed stromal keratitis during late syphilis. One patient with developmental signs of congenital syphilis had bilateral stromal keratitis. The others were otherwise healthy when they presented with unilateral, nonulcerative, infiltrative keratitis with stromal edema of the peripheral or paracentral cornea and mild to moderate corneal vascularization. All had an appropriate response to topical corticosteroid therapy, and two recovered good vision. Stromal keratitis recurred in two patients months to years later. CONCLUSIONS: Nonulcerative stromal keratitis presents in adults with syphilis as marginal, central, or multifocal stromal inflammation with neovascularization that responds to corticosteroid therapy but occasionally recurs.

Administration, Topical↗
PubMed2006

The incidence and risk factors for developing dry eye after myopic LASIK.

PURPOSE: To determine the incidence of dry eye and its risk factors after myopic laser-assisted in situ keratomileusis (LASIK). DESIGN: Single-center, prospective randomized clinical trial of 35 adult patients, aged 24 to 54 years, with myopia undergoing LASIK. METHODS: setting and study population: Participants were randomized to undergo LASIK with a superior or a nasal hinge flap. They were evaluated at 1 week and 1, 3, and 6 months after surgery. intervention: Bilateral LASIK with either a superior-hinge Hansatome microkeratome (n = 17) or a nasal-hinge Amadeus microkeratome (n = 18). main outcome measures: The criterion for dry eye was a total corneal fluorescein staining score > or =3. Visual acuity, ocular surface parameters, and corneal sensitivity were also analyzed. Cox proportional-hazard regression was used to assess rate ratios (RRs) with 95% confidence intervals. RESULTS: The incidence of dry eye in the nasal- and superior-hinge group was eight (47.06%) of 17 and nine (52.94%) of 17 at 1 week, seven (38.89%) of 18 and seven (41.18%) of 17 at 1 month, four (25%) of 16 and three (17.65%) of 17 at 3 months, and two (12.50%) of 16 and six (35.29%) of 17 at 6 months, respectively. Dry eye was associated with level of preoperative myopia (RR 0.88/each diopter, P = .04), laser-calculated ablation depth (RR 1.01/microm, P = 0.01), and combined ablation depth and flap thickness (RR 1.01/microm, P = 0.01). CONCLUSIONS: Dry eye occurs commonly after LASIK surgery in patients with no history of dry eye. The risk of developing dry eye is correlated with the degree of preoperative myopia and the depth of laser treatment.

Adult↗
PubMed2006

ESCRS study of prophylaxis of postoperative endophthalmitis after cataract surgery: Case for a European multicenter study.

PURPOSE: To present the development and design of the European Society of Cataract & Refractive Surgeons multicenter study of the prevention of postsurgical infective endophthalmitis after phacoemulsification and to describe the process for its successful implementation and conduct. SETTING: Twenty-four ophthalmology units and eye clinics in Austria, Belgium, Germany, Italy, Poland, Portugal, Spain, Turkey, and the United Kingdom, with an administrative office in Ireland, coordinating center in England, and data management and statistical unit in Scotland. METHODS: This partially masked randomized placebo-controlled multinational clinical study was designed to evaluate prospectively the prophylactic effect of intracameral cefuroxime and/or perioperative topical levofloxacin on postoperative endophthalmitis after cataract surgery. Random allocation was based on a 2 x 2 factorial design that included participating centers as a class variable. Real-time electronic data collection monitored study progress and provided weekly outcome tables, monthly recruitment summaries, and quarterly analytical reports for the study's Data Monitoring Committee, which evaluated the safety and efficacy by Internet-based conferences. RESULTS: A 2-year lead time was required to meet harmonized standards of clinical research in the European Union, obtain ministerial authorization in 3 countries, gain institutional approvals at 24 hospitals, and procure indemnity insurance for surgical centers. Informed consent instruments, designed to comply with national health policies, were translated into 8 languages. The use of information technology to collect study data enabled the organizers to evaluate individual eligibility at enrollment, adherence with study medications during and after surgery, and postoperative status during follow-up. CONCLUSION: This international cooperative study provided the opportunity to estimate the current incidence of endophthalmitis after cataract surgery in Europe and determine whether 1 or both of 2 antimicrobial regimens reduces the risk for postsurgical intraocular infection.

Administration, Topical↗
PubMed2005

Eye-banking risk factors for fungal endophthalmitis compared with bacterial endophthalmitis after corneal transplantation.

PURPOSE: To track the relative frequency and explore possible risk factors of fungal compared with bacterial endophthalmitis after corneal transplantation. DESIGN: Case-comparison study nested in a surveillance registry. METHODS: We examined, among recipients who underwent surgery from January 1991 through December 2003, demographic and eye-banking characteristics of postkeratoplasty endophthalmitis cases that were reported to the Eye Bank Association of America by US eye banks. Potential predictors of fungal compared with bacterial endophthalmitis were examined using multiple logistic regression. RESULTS: Of 234 reported cases of postkeratoplasty endophthalmitis reported by US eye bank, 46 cases (19.7%) were fungal, and 130 cases (55.6%) were bacterial. Concordant cultures of the residual donor corneoscleral rim or preservation medium occurred significantly more often with fungal than bacterial endophthalmitis (P = .009). After the introduction of Optisol-GS, the odds of bacterial relative to fungal endophthalmitis decreased by 77% (95% confidence interval, 44% - 91%). After adjustment for the preservation method and other eye-banking variables, the odds of fungal endophthalmitis was 3.4 (95% confidence interval, 1.6 - 7.4) times that of bacterial endophthalmitis, when donor corneal preservation was 4 days or longer. CONCLUSIONS: The frequency of postkeratoplasty bacterial endophthalmitis compared with fungal endophthalmitis fell after widespread use of a corneal preservation medium supplemented with gentamicin and streptomycin. Further improvements in corneal preservation procedures are needed.

Aged↗
PubMed2005

Climatology of dematiaceous fungal keratitis.

PURPOSE: To explore how seasonal climate patterns may influence the epidemiology of human keratomycosis. DESIGN: Retrospective ecological study. METHODS: The seasonality of 52 episodes of dematiaceous fungal keratitis occurring along the Gulf of Mexico from 1972 to 2004 was examined. The temperature and relative humidity on the date of onset of 36 eyes with Curvularia keratitis was then compared with regional atmospheric conditions. RESULTS: A relative increase in the diagnosis of dematiaceous fungal keratitis occurred during late summer and persisted throughout autumn. The onset of Curvularia keratitis clustered in warm, humid months. CONCLUSIONS: Ocular phaeohyphomycosis, including curvulariosis, varies with seasonal weather in the subtropics.

Ascomycota↗
PubMed2005

Pathways of corneal and ocular surface inflammation: a perspective from the cullen symposium.

The goal of this symposium was to coalesce information presented by 22 investigators in the field of corneal and ocular surface inflammation into common pathways of inflammation. The perspective elucidated in this article defines the components of the normal ocular surface immune architecture and describes the consensus reached on the mechanisms/pathways involved in 1) acute inflammation; 2) late-stage (chronic) response; and 3) allergic disease. Seven diagrams didactically illustrate mechanisms. This paper is the introductory article in a supplement containing 18 articles by the symposium participants.

Journal Article↗
PubMed2005

Inflammatory response to fungal keratitis.

Ocular fungal infections occur worldwide and are important contributors to vision loss. While many aspects of the microbe and host interaction involved in fungal keratitis remain undefined, two aspects known to affect susceptibility are disruption of the epithelial barrier and immunosuppression of the host. Our recent pathogenesis studies using an experimental murine model have provided insight into the influence of these factors on keratomycosis. Increased susceptibility was associated with greater neutrophilic infiltration, greater fungal invasion of the corneal stroma, up-regulation of matrix metalloproteinase-9, and morphogenic switching from yeast to hyphae. Understanding the pathogenic events of fungal keratitis will identify potential targets for therapeutic intervention of these sight-threatening infections.

Journal Article↗
PubMed2005

Acanthamoeba keratitis during orthokeratology.

PURPOSE: To report an infectious complication of overnight rigid gas-permeable contact lenses. METHODS: Case report and medical literature review. RESULTS: A 16-year-old girl developed laboratory-confirmed acanthamoebic keratitis during orthokeratology for myopic reduction. Recent case reports suggest that Acanthamoeba is a cause of microbial keratitis associated with gas-permeable contact lenses among teenagers and young adults undergoing orthokeratology. CONCLUSIONS: Acanthamoeba keratitis is an emerging complication of orthokeratology in young myopes.

Acanthamoeba Keratitis↗
PubMed2004

Immunosuppression affects the severity of experimental Fusarium solani keratitis.

We have established a mouse model of corneal fusariosis that permits the evaluation of fungal infection and pathogenesis. Corneas of immunocompetent and cyclophosphamide-treated adult BALB/c mice were topically inoculated with Fusarium solani after corneal scarification. Eyes were scored for corneal involvement daily for 8 days and at 2 weeks after infection. Eyes were enucleated at various time points for quantitative fungal recovery and histopathological examination. An inoculum-dose response was observed in cyclophosphamide-treated mice, and fungi were recovered from the infected eyes by quantitative microbial culturing. Treatment with cyclophosphamide increased disease severity and delayed fungal clearance. Fungal hyphae, inflammatory cells, and stromal edema were histologically evident within corneal tissue and correlated with disease severity. Although the mouse cornea resists fungal infections, F. solani keratitis could be induced in immunosuppressed mice after surface scarification, which resulted in infection and clinical disease that could be evaluated both in vivo and in vitro.

Animals↗
PubMed2004

The effect of off-the-visual-axis retinoscopy on objective refractive measurement.

PURPOSE: To determine the effect of off-axis retinoscopy on objective refractive measurement. DESIGN: Prospective experimental study. METHODS: Eight volunteers underwent cycloplegic retinoscopy of their right eye on-the-visual-axis, and 5, 10, 15, and 20 degrees off-the-visual-axis in adduction. A single masked examiner performed all retinoscopy with random order of the patient and axis refracted. RESULTS: The average spherical retinoscopic value at 0, 5,10,15, and 20 degrees of off-axis alignment was -0.40, -0.90, -1.00, -1.38, and -1.80 diopters, respectively. The average spherical equivalent retinoscopic value obtained for each of the above positions of eye alignment was -0.02, -0.59, -0.45, -0.64, and -0.98 diopters, respectively. The induced cylinder power increased by an average of 3% for each degree of off-axis retinoscopy, though the axis of the cylinder was not predictable. CONCLUSION: Objective refractive measurement by retinoscopy is significantly altered by off-the visual-axis retinoscopy. The induced error may be clinically important even with small degrees of eccentricity.

Adult↗
PubMed2004

Herpes simplex virus keratitis in children.

PURPOSE: To describe the spectrum and recurrence of herpes simplex virus (HSV) keratitis in children and adolescents. DESIGN: Retrospective cohort study. METHODS: Twenty-three patients younger than age 16 years were diagnosed with HSV keratitis at one institution. RESULTS: All children presented with dendritic or punctate epithelial keratitis, and stromal keratitis occurred concurrently with epithelial keratitis in 14 patients (61%). Six patients (26%) had bilateral HSV keratitis. Eleven patients (48%) developed recurrent HSV keratitis at a median of 15 months after the first documented episode. Amblyopia occurred in three children. CONCLUSION: Children with herpetic keratitis may have bilateral ocular involvement and are at risk for recurrent keratitis and amblyopia.

Acyclovir↗
PubMed2004

Corneal thickness in children.

OBJECTIVE: To determine normal central and paracentral corneal thickness measurements in the pediatric population and to determine if these measurements are consistent across different pediatric age groups and different racial groups. DESIGN: Prospective observational case series. METHODS: Pachymetry measurements were performed on 198 eyes of 108 children. The measurements were taken centrally as well as at four paracentral sites 3 mm from the corneal center at the 3, 6, 9, and 12 o'clock positions. The two-tailed t test was used for comparison of the continuous means for values of corneal thickness. Analysis of variance (ANOVA) was performed to determine differences among age and ethnic groups RESULTS: The mean central corneal thickness (CCT) was 549 +/- 46 microm. Paracentral corneal thickness mean values, as measured 3 mm from the corneal center, were as follows: superior, 575 +/- 52 microm; nasal, 568 +/- 50 microm; inferior, 568 +/- 51 microm; and temporal, 574 +/- 47 microm. The mean CCT values were significantly thinner than at each of the mean paracentral points (P < .05 for each comparison, paired t test). Paracentral corneal thickness measurements demonstrated no significant differences between locations (P > .05, variance analysis). The mean CCT +/- SD for each age group was as follows: 6 to 23 months, 538 +/- 40 microm; 2 to 4 years, 546 +/- 41 microm; 5 to 9 years, 566 +/- 48 microm; and 10 to 18 years, 554 +/- 35 microm (ANOVA P = .012). ANOVA performed on central pachymetry values demonstrated no significant differences among racial subgroups. CONCLUSIONS: Pediatric central and paracentral corneal thicknesses increase slowly over time and reach adult thicknesses at 5 to 9 years of age.

Adolescent↗