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Cindric Boris, Serdarevic Muhammed, Duriau Jean. Après la guerre, la reconstruction comme opportunité : L'expérience d'Europan à Sarajevo. In: Les Annales de la recherche urbaine, N°91, 2001. Villes et guerres. pp. 61-64.

The probability method of analysis of astigmatism variations respects both astigmatism components, quantity and axis. The two random variable model that we introduce here analyses cylinder variations and axial variations. After describing the contingency table and the probability table. Expectation of each component and its confidence interval are calculated together with the variance and the standard deviation. Covariance and correlation are calculated. If we want to compare different groups we test cylinders with cylinders and axes with axes. This method does not distort reality and is applicable to the semi meridians from 0 degree to 360 degrees. Only large samples of patients can be studied by this method.

Several studies have analysed postoperative or spontaneous variations in astigmatism. The methods of quantification of these variations, frequently used in these studies, are based on different ways of calculating: subtraction, vectorial or polar methods: Naylor, Jaffe and Clayman, Cravy, Naeser, Russell et al. and recently, Holladay et al. Although these methods have the advantage of taking into account the axial component of astigmatism and are useful for a single patient, they have many problems and they are more and more numerous (five in the last three years). We have computerized these formulae on a personal computer and studied their performances when the cylinder power decreases without modification of the axes, when the axes are modified without modification of the cylinder power and when the two axes change with the same angular difference. These calculations demonstrate that these formulae are not linear and introduce statistical errors before the statistical decision tests. Moreover, their application is only possible for evaluation of astigmatism axes between 0 degree to 180 degrees and not for semi meridians and corneal topography.

We compared histologically and ultrastructurally donor buttons and recipient beds trephined mechanically with those trephined by the Excimer laser at 193 nm. The laser allowed for superior cutting precision and perfect centering. This non-contact method obviated the need for any pressure or suction during trephination, thereby eliminating problems associated with distortion of corneal topography. We studied wound healing after penetrating keratoplasty with mechanical and laser trephination in an animal model. The laser did not adversely affect wound healing processes.