A doctoral dissertation defended at the University of Murcia has measured the aberrations generated by the progressive power lenses, used to correct short-distance low vision that occurs in older people.
Its author, Eloy Villegas Angel Ruiz, has focused in his study in the alternative that has proliferated in recent decades to increase the power of the eye in near vision, such as progressive power lenses, of which there is little information on higher-order aberrations that occur in them and their impact on visual quality.
These eyeglass lenses provide a continuous vision at all distances due to a progressive shift of power from the upper ball, which is used for distance vision, to the lower, which is used for near vision, leaving the area progression of power for intermediate distances.
Despite advances in design and manufacturing, says the author in his thesis, on today is not possible to produce a progressive spherical power surface without causing astigmatism, as well as distortion.
In this work we have measured the wavefront aberrations in progressive lenses spatially resolved, either isolated or combined with the eye, developing a system with a Hartmann-Shack sensor.
The thesis concludes that the art lenses generate optical aberrations, although its distribution depends on the design philosophy.
Aberration, he added, mainly astigmatism, progressive lenses behave like a water bed, where water is astigmatism that can be moved but not deleted.
The dissertation, which was directed by Professor of the University of Murcia Pablo Artal, obtained excellent cum laude.
Source: Universidad de Murcia