<p>Base Curve of Progressive Addition Lenses Influences Clear Vision and Stereopsis Area</p>

Progressive Addition Lenses Ang

Progressive addition lenses--measurements and ratings.

BACKGROUND This study is a followup to a previous study in which the optics of several progressive addition lens (PALs) designs were measured and analyzed. The objective was to provide information about various PAL designs to enable eye care practitioners to select designs based on the particular viewing requirements of the patient. METHODS The optical properties of 12 lenses of the same powe...

A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children.

PURPOSE The purpose of the Correction of Myopia Evaluation Trial (COMET) was to evaluate the effect of progressive addition lenses (PALs) compared with single vision lenses (SVLs) on the progression of juvenile-onset myopia. METHODS COMET enrolled 469 children (ages 6-11 years) with myopia between -1.25 and -4.50 D spherical equivalent. The children were recruited at four colleges of optometr...

A variational-difference numerical method for designing progressive-addition lenses

We propose a variational-difference method for designing the optical free form surface of progressiveaddition lenses (PALs). The PAL, which has a front surface with three important zones including the far-view, near-view and intermediate zones, is often used to remedy presbyopia by distributing optical powers of the three zones progressively and smoothly. The problem for designing PALs could be...

Vision: Simple stereopsis

By limiting stereopsis to measuring the distance of moving objects against a stationary background, insects can employ simple stratagems for solving the problems of stereoscopic range finding.