Aims: In many countries the number of corneal donations is far too low to graft all patients on waiting lists within reasonable time. The aim of this study was to define specifically what practical changes are to be implemented to fully meet corneal graft demand. Methods: The list of potential donors drawn by the coordination team from 1 January to 31 December 1999 was compared with that of all patients who had died during the same period. In each identified record, the parameters which permitted or precluded effective collection of cornea specimens were analysed, and the reasons why other records were not identified were investigated. Results: Among the 1112 patients who died in 1999, coordinating nurses were able to identify 451 records (40.5 %) including 329 patients aged between 18 and 85 years (29.5%). After excluding 184 patients (55.9 %) who presented with medical contraindications, the coordinating nurses were able to meet the relatives of only 55 out of 145 patients (38%) and obtained their agreement in 39 cases (71% approval rate). Therefore, relatives' refusal was the cause for the absence of collection in only 5.5% of cases (16/290). The number of cornea procurements amounted to 11.8% of identified records and 3.5% of all deceased patients. Conclusion: French law and regulations regarding tissue collection are based on consent presumption but it requires that verifications be made with the relatives to ensure that potential donors were not, before their death, opposed to such tissue procurement. That provision implies a high degree of organisation on the part of coordinating teams. It was demonstrated that donation shortage is no longer the result of relatives' refusal but rather because of logistical difficulties (potential donors not identified and problems in reaching relatives). It appears necessary therefore to strengthen coordinating teams with sufficient staff levels for wider donor identification. Those teams should also find ways to keep closer contact with relatives, so as to meet the maximum transparency targets required by public opinion and regulations and to graft all patients awaiting corneal transplantation.

We demonstrate that a high positive response (71.5%) can be obtained from the donor's family when a trained and motivated group manages the post-mortem cornea donation request.

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For timed event graphs, linear models were obtained using Max-Algebra. This paper presents a method to control such systems. After describing the optimal solution of a model tracking problem, we propose a feedback control structure in order to take into account a possible modeling error. We present its construction, its main properties and an algorithm for its practical implementation. An illustrative example is provided.

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