Association between positive corneal rim cultures and microbiology screening protocols in Ontario.

OBJECTIVE: (i) To assess the rate of positive microbiological cultures of corneas prepared by the Eye Bank of Canada (Ontario Division) between January 1, 2012, and December 31, 2013; (ii) to review the microbiology protocols at the 5 major transplant centres in Ontario; and (iii) to assess the incidence of endophthalmitis during the study period. DESIGN: Retrospective chart review. PARTICIPANTS: A total of 4186 consecutive cultured corneal tissues prepared by the Eye Bank from January 1, 2012, to December 31, 2013. METHODS: Rates of culture-positive cornea rims and incidence of postkeratoplasty endophthalmitis at 5 surgical centres in Ontario were determined, and the protocols used to culture rims at each site were concurrently reviewed. Culture results were analyzed via logistic regression for positive cultures. RESULTS: The rate of positive cultures at each sites were as follows: centre A, 3.74%; centre B, 3.26%; centre C, 0.51%; centre D, 0.48%; and centre E, 0.04%. Centres A, B, and D were noted to have significantly higher positive rates than centre E. In comparing microbiology protocols, longer incubation period (11 days) was 12 times more likely to be associated with higher positive culture rates than shorter period (4-5 days). Six-month follow-up of all keratoplasties revealed zero reported cases of endophthalmitis. CONCLUSIONS: A literature review regarding the predictive value of routine culturing reveals conflicting data. Our findings suggest that differences in the microbiology protocols directly influence the rates of positive rim cultures. Without a standardized protocol, it is not possible to evaluate the predictive value of routine corneal rim culturing in predicting postkeratoplasty endophthalmitis.

Evolving surgical techniques of and indications for corneal transplantation in Ontario: 2000 - 2012.

OBJECTIVE: To evaluate trends in indications for and preferred surgical techniques of corneal transplantation in Ontario over a 12-year period. DESIGN: Retrospective review of recipient information forms collected by Eye Bank of Canada (Ontario Division). PARTICIPANTS: Patients who received corneal transplantation in Ontario between 2000 and 2012, totaling 11,725 corneal transplants performed. METHODS: Database containing information collected from recipient information forms maintained by the Eye Bank of Canada (Ontario Division) was reviewed. Corneal transplants performed between July 1, 2000, and June 30, 2012, in Ontario were analyzed. Surgeons complete recipient information forms at the time of corneal transplant surgery. Of the 11,725 available recipient information forms, 10,906 (93%) were sufficiently complete to meet the inclusion criteria and were included in the study. RESULTS: Since 2009, Fuchs endothelial dystrophy overtook pseudophakic corneal edema as the leading indication for corneal transplantation. Since the shift toward lamellar keratoplasty in 2006, there has been a significant decrease in number of corneal transplants performed with penetrating keratoplasty (PKP; p = 0.0016) and a significant increase in Descemet stripping automated endothelial keratoplasty (DSAEK; p = 0.0069) and deep anterior lamellar keratoplasty (p = 0.0108). The gap between number of PKPs and DSAEKs performed each year is progressively narrowing. From July 1, 2011, to June 30, 2012, 514 PKPs were performed compared with 420 DSAEKs. From 2011 to 2012, 83% of corneal transplants indicated by Fuchs endothelial dystrophy were performed with DSAEK, whereas only 13% were performed with PKP. CONCLUSIONS: Six years since initial implementation, partial thickness transplantation continues to increase in popularity. Corneal tissue supply and demand will need to reflect these changes in the field of corneal transplantation.

Sustainability of Routine Notification and Request legislation on eye bank tissue supply and corneal transplantation wait times in Canada.

OBJECTIVE: To assess whether provinces with Routine Notification and Request (RNR) legislation have sustained increases in corneal tissue supply and decreases in wait times for corneal transplantation surgery. DESIGN: Cross-sectional survey of Canadian corneal transplant (CT) surgeons and eye banks. PARTICIPANTS: Canadian CT surgeons and representatives from the 10 Canadian eye banks. METHODS: Voluntary and anonymous surveys were distributed between July and October 2009. Eligible CT surgeons were defined as ophthalmologists who practice in Canada; currently perform Penetrating keratoplasty (PKP), Deep anterior lamellar keratoplasty (DALK), Deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), or Descemet membrane endothelial keratoplasty (DMEK); and have obtained tissues from a Canadian eye bank. RESULTS: From 2006 to 2009, for provinces with RNR legislation and where data are available, mean wait times from date of diagnosis to date of CT surgery have increased: in Ontario, from 31 ± 34 weeks to 36 ± 27 weeks; in British Columbia, from 39 ± 20 weeks to 42 ± 35 weeks; in Manitoba, from 32 ± 23 weeks to 49 ± 36 weeks. In addition, the amount of corneal tissue in RNR provinces suitable for transplant, with the exception of British Columbia, has declined between 2006 and 2008: in Ontario, 1186 tissues to 999 tissues (16% decline); in Manitoba, 92 tissues to 83 tissues (10% decline); in New Brunswick, 129 tissues to 98 tissues (24% decline). CONCLUSION: Although initially effective, RNR legislation has not sustained an increase in corneal tissue availability nor has it shortened wait times in most provinces. Incorporation of community hospitals into the RNR catchment, improved enforcement, and continued education of hospital staff regarding the RNR process may be effective in making this legislation more sustainable in the long term.

Evolving surgical techniques of and indications for corneal transplantation in Ontario from 2000 to 2009.

OBJECTIVE: To determine the changes in the leading indications for and the preferred surgical techniques of corneal transplantation in Ontario over a 9-year period. DESIGN: Retrospective review of Eye Bank of Canada (Ontario Division) records. PARTICIPANTS: Recipients of corneal transplants performed in Ontario between 2000 and 2009, totaling 6240 patients. METHODS: Records of all corneal tissues sent for transplantation in Ontario by the Eye Bank of Canada (Ontario Division) from July 1 2000 to June 30 2009 were reviewed. The records consist of recipient information forms completed by surgeons at the time of corneal transplant surgery. Of the 8186 available recipient information forms, 7755 (94.7%) were sufficiently complete to meet the inclusion criteria. RESULTS: The leading indications for corneal transplantation were pseudophakic corneal edema (28.3%), regraft (21.5%), Fuchs dystrophy (16.6%), and anterior keratoconus (13.8%). Beginning in 2006, there has been a shift in the proportion of corneal transplants performed using Descemet's stripping automated endothelial keratoplasty (DSAEK) and deep anterior lamellar keratoplasty, from 2.4% to 36.1% of all corneal transplants. Concomitantly, DSAEK has replaced penetrating keratoplasty (PKP) as the technique of choice when corneal transplantation is indicated for Fuchs' dystrophy (139 DSAEKs vs. 68 PKPs in 2009) and for pseudophakic corneal edema (118 DSAEKs vs. 115 PKPs in 2009). CONCLUSION: The indications for PKP in this study agree with the North American literature. In recent years, partial-thickness transplants have gained favor over PKP for select indications in Ontario. These changes reflect the future direction of corneal transplantation and will have implications on the supply of and demand for tissues.

In situ versus whole-globe harvesting of corneal tissue from remote donor sites: effects on initial tissue quality.

PURPOSE: There are 2 methods of corneal tissue procurement currently in widespread use: in situ extraction of the corneal button directly to preservation media and whole-globe enucleation of eyes with removal of the button to preservation media at a later time. This study evaluates the effects of these 2 procurement procedures on the initial quality of donor corneal tissue. METHODS: Slit-lamp examination results and endothelial cell counts were compared for a total of 468 donor corneas harvested at 2 remote locations: one where in situ procurement was practiced and the other that used whole-globe enucleation procedures. RESULTS: In both univariate and multivariate analysis, in situ corneas were found to have a lower incidence of moderate or severe haze and folds in Descemet membrane. No differences in mean endothelial cell counts were noted between the 2 populations of donated tissue. CONCLUSIONS: In situ procurement of corneal tissue results in higher initial corneal tissue quality than whole-globe procedures.