Infectious disease risk factors of corneal graft donors.

OBJECTIVE: To determine how donor health status affects the risk of infection after corneal transplant. METHODS: An adverse reaction surveillance registry was used to conduct a matched case-control study among transplanted donor corneas from January 1, 1994, to December 31, 2003. Cases comprised 162 reports of endophthalmitis after penetrating keratoplasty including 121 with microbial recovery, of which 59 had concordant donor and recipient microbial isolates. Two controls were matched to each case by surgery date. Conditional logistic regression estimated adjusted odds ratios with 95% confidence intervals according to the premortem status of decedent donors. RESULTS: Postkeratoplasty endophthalmitis was associated with recent hospitalization (odds ratio, 2.84; 95% confidence interval, 1.61-4.98) and fatal cancer (odds ratio, 2.46; 95% confidence interval, 1.53-3.97) among donors. Endophthalmitis appeared more likely with tissues transplanted longer than 5 days after donation (odds ratio, 1.55; 95% confidence interval, 1.02-2.35). The prevalence of concordant microbial isolates from donors and recipients was greater among fungal endophthalmitis than among bacterial endophthalmitis (P < .001). CONCLUSIONS: Corneal grafts with eye tissue obtained from donors dying in the hospital or with cancer may have an increased risk of postsurgical endophthalmitis, possibly due to donor-to-host microbial transmission. Together with donor screening and processing, improvements in microbiological control may reduce infection associated with corneal transplant.

Quality assessment and microbiologic screening of donor corneas.

PURPOSE: To identify possible predictors of donor corneal contamination. METHODS: Relationships between eye-banking characteristics of donor corneas and surgical corneoscleral rim culture results were examined in a retrospective case-control study by using logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: Of 263 donor corneal rims, microbial recovery occurred from 23 (9%), including 6 yielding Clostridium perfringens. After adjusting for outdoor temperature and death-to-preservation duration, a positive rim culture occurred more often among tissues having an acceptable but less favorable biomicroscopic rating (OR, 4.22; 95% CI, 1.27-13.98). CONCLUSIONS: This exploratory study suggests that slit-lamp assessment of corneal appearance may correlate with subsequent microbiologic results. Ensuring optimal selection and preservation of the donor cornea may contribute to the safety of eye banking.

The prognostic role of donor corneoscleral rim cultures in corneal transplantation.

PURPOSE: To examine the discriminatory performance of donor corneoscleral rim cultures for predicting endophthalmitis after corneal transplantation. DESIGN: Systematic literature review. PARTICIPANTS: Studies that reported the prevalence of donor rim cultures after refrigerated preservation of donor corneas distributed for keratoplasty. METHODS: Random-effects meta-analysis estimated pooled sensitivity, specificity, likelihood ratios, and diagnostic odds ratios. Meta-regression and stratification explored study-level reasons for diagnostic performance. MAIN OUTCOME MEASURES: Incidence of postkeratoplasty endophthalmitis. RESULTS: Of 17,614 corneal grafts, 2459 (14%) had a positive donor rim culture and 31 (0.2%) developed endophthalmitis. Twenty-one had concordant donor and recipient isolates, including 10 with Candida species. The sensitivity of donor rim cultures among 10 studies reporting postsurgical endophthalmitis was 67% (95% confidence interval [CI], 47%-83%), and specificity averaged 85%. Endophthalmitis occurred 12 (95% CI, 5-29) times more often among recipients of a culture-positive donor cornea. With Bayesian analysis, a culture-positive donor cornea would raise the infection risk to 1%, whereas fungal isolation from the donor rim predicts a 3% probability of fungal endophthalmitis. Pooling of studies was limited by a significant discrepancy among reports that could not be explained by differences in antibiotic supplementation of the preservation medium, method of culture inoculation, or type of culture medium. CONCLUSION: Endophthalmitis after penetrating keratoplasty is more likely with a culture-positive donor rim, notably candidal endophthalmitis from fungal contaminants, but better evidence is needed to determine the prognostic value and manner of routine microbiological screening.

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.

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.

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.