Besides the monochromatic Seidel aberration there are also axial or longitudinal chromatic aberration (LCA) and lateral or transversal chromatic aberration that affect the focus as a function of the wavelength of the illumination light. Zernike polynomials that are widely used in analysis of the aberrations in the human eye. The Zernike polynomials have one important limitation: their coefficients are only correct for a specific pupil diameter. Therefore, the pupil diameter must be included in all reports of measurements of wavefront aberrations that are based on the Zernike polynomials. Adaptive optics is a technology to compensate for wavefront distortions. A concise description of how the Hartmann-Shack Aberrometer is used to analyze aberrations in the patient’s eye is given. The aberrations of the wavefront are measured with a wavefront sensor and a deformable mirror is used to correct the wavefront distortions. Adaptive optics is being incorporated into many types of ophthalmic imaging devices and it results in improved resolution and contrast of the images of the human eye.