Biconvex, Wavefront-designed anterior aspheric surface
, posterior achromatic diffractive surface designed to reduce chromatic aberration for enhanced contrast sensitivity and
The retinal image size is reduced due to the aspheric surface
and flatter base curve; care must be taken to order both lenses from the same manufacturer to ensure that any MAR coatings or tints match.
Lenses are limited by the inherent diffraction efficiency of the aspheric surface
, so they yield a lower overall transmission than comparable aspherized achromats.
The biggest challenge I faced making this scope was ensuring that the secondary's aspheric surface
was a smooth figure of revolution.
Numerical Control Interpolation Algorithm of Aspheric Surface
Based on the Genetic Algorithms and Neural Network
The human cornea is neither a true spherical, nor a true toric surface, but is a relatively complex aspheric surface
with the degree of asphericity varying in each of the principle meridians.
Clinical studies have not been conducted with the Akreos Advanced Optics Aspheric lens to assess the effect of the added aspheric surface
to the parent lens model Akreos on spherical aberration, visual acuity and contrast sensitivity.
One of the technical highlights is the plastic "combiner" screen, which has an aspheric surface
31) In an attempt to minimise these symptoms, many MIOL designs incorporate an aspheric surface
to maximise contrast sensitivity and visual function.
The hydrophobic acrylic material helps lower chromatic dispersion for improved vision and the lens uses a patented, wavefront-designed aspheric surface
to compensate for spherical aberration of the cornea.
Therefore an aspheric surface
is spherical at the very centre but becomes astigmatic away from the optical centre.
Interferometric asphere metrology has traditionally required the use of a null lens or computer-generated hologram that must be specially designed for each different aspheric surface