The astigmatic meridian can also be identified using corneal wavefront technology or paraxial curvature matching. Radial and astigmatic keratotomies, epikeratophakia and the first steps on laser refractive procedures. This will compensate for the astigmatic aberration of the eye. The Fourier transform of an astigmatic image is usually elliptically shaped. Clinical studies support vector planning both in healthy astigmatic eyes and in eyes with keratoconus. Astigmatic, distorted surfaces potentially introduce serious degradations in optical system performance. Compact disc players use an astigmatic lens for focusing. Systems in which the two astigmatic surfaces coincide are termed anastigmatic or stigmatic. In addition to conical and cylindrical pencils, optics deals with astigmatic pencils as well. New phenomena unique to rings appeared, including lock-in, pulling, astigmatic beams, and special polarizations. This method is however problematic, especially for astigmatic prescriptions. Hal is astigmatic, and requires special glasses. Astigmatic is a studio album by Polish jazz pianist and composer Krzysztof Komeda.