The search for improved optical fiber glasses with the potential for losses lower than those of fused silica-based composition could be expedited if the relevant optical parameters could be calculated. This is particularly important for the magnitude and wavelength of the minimum in the loss curve, since these values have been experimentally established only for fused silica. Details are given of a way of estimating such data. A summary is also given of a way of calculating the wavelength at which the material dispersion parameter is zero and of calculating the material dispersion slope at that wavelength. A listing is given of calculated and some experimental values of the material dispersion slope. The availability of these parameters should expedite the search for new and improved glasses.