Bifocal glasses have been around for hundreds of years, but no line bifocal glasses were only invented in the last hundred years and have technology that is advancing every day.
What is a Bifocal, anyways?
A bifocal, or bifocal lens, is a special type of glasses that are designed to provide clear vision in the distance and up close.
By having two different powers of lenses put into a single lens, the bifocal is able to correct vision at two different distances.
There are many styles and types of bifocal lenses, but they all share a common design of the top portion of the lens providing clear vision for the distance (think about driving and looking at street signs) and the bottom of the lens providing clear vision for near work (think about reading a book or looking at a phone).
Who Needs Bifocal Lenses?
Bifocals have become synonymous with aging and elderly people; this is because the need for a bifocal comes primarily from the process known as presbyopia.
Presbyopia occurs with age and causes the eyes to be unable to focus up close and vision up close to become blurry.
Typically, presbyopia begins to affect vision in the early to mid-forties but can affect people younger or older depending on several factors.
It is also possible that someone needs a bifocal for another condition, but presbyopia is the primary cause of bifocal wear.
What is Different About No Line Bifocals, Progressive Lenses?
A no line bifocal is a special type of lens that can change the power of the lens, and thus the distance at which is provides clear vision, gradually throughout the lens.
Since the power changes – or progresses – through the lens, another common name for no line bifocals is progressives.
Just like a line bifocal, the no line bifocal corrects for clear distance vision in the top of the lens, then as the lens gets closer to the bottom of the frame, it begins to correct for intermediate distance vision and finally, near vision in the bottom.
The notable difference in the two designs is the addition of intermediate vision correction that no line bifocals provide. This clear vision can be at a distance of about two feet to about four feet.
Why Would Someone Need a Progressive Lens?
In many ways, every person who wears reading glasses or bifocals could benefit from switching to a progressive lens.
No line bifocals are generally viewed as more attractive because there is not a visible line in the middle of the lens.
Aside from looks, the progressive lenses provide the additionally clarity in the intermediate region that bifocals lack. This zone is often where a computer sits, where someone sitting across a desk or table is, and is about the reach of the arms.
The intermediate zone is a very busy area, and a bifocal can leave someone having to move closer or farther just to see clearly.
How Do You Get a Progressive Lens?
A no line bifocal requires a prescription from an eye doctor and must be specially fit to optimize the views through each region of the progressive lens.
Scheduling an exam with your eye doctor to discuss progressive lens options is a great start!
