Difference between revisions of Bifocals

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Bifocals are glasses that have two different strengths of lenses depending on where you look through the lens.  Typically bifocals for [[presbyopia]] and [[myopia]] have the lower section (for use during reading) 1-2 [[diopters]] weaker than the upper section.  
Bifocals are glasses that have two different strengths of lenses depending on where you look through the lens.  Typically bifocals for [[presbyopia]] and [[myopia]] have the lower section (for use during reading) 1-2 [[diopters]] weaker than the upper section.  
The EM method uses separate [[differentials]] and [[normalized]] lenses rather than bifocals, making it easier to adjust your [[lens selections]] separately.
The Reduced Lens method uses separate [[differentials]] and [[normalized]] lenses rather than bifocals, making it easier to adjust your [[lens selections]] separately.
 
Note that the term ''Bi-focal'' is often used interchangeably for ''Binocular'', for example when talking about [https://endmyopia.org/pro-topic-how-to-reduce-prescription-complexity/ Bi-focal Reduction], it mean Left and Right sph should be reduced as same diopter.


=Multifocals=
=Multifocals=

Latest revision as of 19:31, 26 July 2023

Bifocals are glasses that have two different strengths of lenses depending on where you look through the lens. Typically bifocals for presbyopia and myopia have the lower section (for use during reading) 1-2 diopters weaker than the upper section. The Reduced Lens method uses separate differentials and normalized lenses rather than bifocals, making it easier to adjust your lens selections separately.

Multifocals

Bifocals are a type of multifocal, any lens with more than one power is a multifocals. Multifocals have a wider variety of available patterns than typical bifocals, such as gradual transitions and alternate patterns of power distribution.

Simultaneous vision lenses

A multifocal solution generally used in contacts, where your eye is looking through both powers of lens at the same time, and your visual cortex works out which part of the image to process for each distance.