  Objectives: To analyze the whole process involved in the production of a new
bifocal Multizone Contact Lens (MCL) for presbyopia.
  Methods: The optical quality of a new MCL was evaluated by ray tracing
software in a model eye with pupil different diameters with the lens centered
and decentered. A stock of low addition (+1.5 D) MCL for presbyopia was ordered
for manufacturing. Power profiles were measured with a contact lens power
mapper, processed with a custom software and compared with the theoretical
design. Nine lenses from the stock were fitted to presbyopic subjects and the
visual performance was evaluated with new APPs for iPad Retina.
  Results: Numerical simulations showed that the trough the focus curve
provided by MCL has an extended depth of focus. The optical quality was not
dependent on pupil size and only decreased for lens decentered with a pupil
diameter of 4.5 mm. The manufactured MCL showed a smoothed power profile with a
less-defined zones. The bias between experimental and theoretical zone sizes
was uniform along the optical zone unless for the most central area. Eyes
fitted with the manufactured MCL showed an improvement in near Visual Acuity
(VA) and near stereopsis. Althouh Contrast Sensitivity (CS) at distance
decreased, the defocus curve for contrast showed an extended depth of focus
correlated to the ray tracing results.
  Conclusions: The understanding of vision with MCL requires a process that
involves design and characterization for detecting any defect that may have
impact in the final visual performance. Keywords: Multifocal contact lenses,
design, characterization, visual performance
