How are wavefronts measured?
In ophthalmology, wavefronts are measured by devices called aberrometers. Aberrometers use wavefronts to objectively measure the overall refractive power error of the eye. They do this by mapping how light rays travel through the eye and by providing maps using colour gradients to represent magnitudes of the refractive errors, which enables ophthalmologists to locate and possibly correct even obscure imperfections that cause vision defects. As the name indicates, an aberrometer measures aberrations, and an aberration is a vision defect that occurs when light rays are improperly bent (refracted) in the eye. An aberration may occur because of a flaw in the structure of the eye. There are lower order aberrations, sphere and cylinder, and there are higher order aberrations such as coma, trefoil and spherical aberration. Patients who complain of glare, halos, starbursts and poor night driving often have increased higher-order aberrations.
