What is Difference Between Bifocal and Multifocal Reading Glasses?
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What is Difference Between Bifocal and Multifocal Reading Glasses?
Views: 0 Author: Danica Yang Publish Time: 2025-07-11 Origin: Site
Bifocal lens and multifocal lens are both used for the presbyopia correction, but they have the fundamental differences in optical design, applicable scenes and user experience. Before comparing the differences between the two, we need to know well about what is bifocal lens and what is multifocal lens.
*What is bifocal reading glasses?
Bifocal reading glasses which we also call it double vision glasses, it is a type of eyeglasses
that specially designed for people with presbyopia. The core feature of bifocal glasses is that it integrate two separate optical areas within a single lens, and the two different areas are separated by a visible seg line to correct vision for both near and far distance. When there's a need to switch between the near vision and far vision within a short time, there's no need to repeatedly take off and put on the glasses by using bifocal glasses.
The distant area of the lens is used for looking at the far objects and there's no need for you to take off the reading glasses.
The nearby area of the lens is used for looking at the near objects, like reading books, reading newspaper and watching cellphones.
One lens is ingeniously designed with multiple functional usage areas to meet the different needs of users at the same time. The lens type of far distance area is plano lens, its surface is flat and has no curvature. We can make this plano lens with blue light blocking lens, it'll protect our eyes better.
The lens type of near distant area is presbyopic lens which comtains the presbyopia correction degrees, like +1.00, +1.50, +2.00, +2.50, +3.00, +3.50 and +4.00, there will be degree stickers on the lens to tell the customers how to choose the right reading glasses.
Lens Area
Lens Position
Lens Functions
Optical Property
Far Distance Area
Upper part of the lens
Correct the distant vision at a distance of 5 meters
Base diopter, such as myopia -3.00 dgrees
Near Distance Area
Bottom part of the lens
Correct the near vision for reading at 30-40 meters
Basic diopter +ADD value. The ADD value is downward correction, the correction required for presbyopia like +1.50D, it will increase with age.
Seg Line
The junction of near and far distance areas
Switching mark
Horizontal straight line or curve line can be visible by naked eyes
The bifocal reading glasses is suitable for the following people.
People with presbyopia, the age of them is usually over 40 years old. As one ages, the elasticity of the lens in the eye decreases and it'll casue the eyes to start to become blurry when looking at close objects.
People with presbyopia who have both myopia and hyperopia, who need to correct the basic reflactive errors when need to see the far distant objects. When to see the nearby objects, it'll need to add +ADD value.
People who don't want to change the glasses frequently when see near or far objects. The bifocal glasses is suitable for the people who need to handle both distant and nearby tasks at same time.
* What is multifocal reading glasses?
Multifocal reading glasses is also known as progressive glasses, it is a high-end eyeglasses that uses a seamless gradual change technology to simultaneously correct vision for the entire range from far to near and from middle to near. The multifocal glasses is specially designed for prople with presbyopia. It has solved the problem of visual dicountinuity in traditional bifocal glasses.
The readers with multifocal lens uses a single lens to create 3 layers of visual space, ensuring that everything is clear from the white board, computer screens to youe mobile phones.
The advantages of multifocal reading glasses:
Total Distance Seamless Vision
When you are driving and wearing the multifocal glasses, you can look at the road by using far area, look at the dashboard by using the middle area, and look at the navigation by using the near area.
Natural Visual Behavior
You only need to tilt your head slighty when you are wearing the multifocal glasses, there's no need to frequently change the style of the glasses. The line of sight will natually move download as the distance from the objects increase, it meet the ergonomic.
There's no boundary lines on the lens, and the design of the invisible areas will not reveal your age.
High-precision Facial Adaptation
The free-form surface technology of multifocal lens, it will adjust point-to -point according to the wearer's face shape and eye usage habits.
The pupil center positioning of multifocal lens can dynamically optimize the visual corridor under different light conditions.
Lens Area
Lens Position
Lens Functions
Optical Property
Far Distance Area
The Upper part of the lens
Can see the objects 5 meters away clearly, such as road signs
Basic degree, like myopia -3.00D
Progressive Area
The middle part of the lens
Transition zone distance, from 40 meters to 1 meter
The degree increases by 0.10 - 0.20D per millimeter
Near Distance Area
The bottom part of the lens
Correct the reading distance of 30 - 40 meters
Basic diopter +ADD value, like +2.00D
Scattering Area
Both sides of the lens
It's optical by-product
Slightly blurring and distortion
The multifocal reading glasses is suitable for the following people.
The people who has presbyopia combined with myopia or presbyopia with hyperopia, they need the multiple distance vision.
The digital workers who spend more than 4 hours per day looking at the electronic screens.
The middle-aged people who pay attention to the appearance.
⚠ The following people are not advised to choose multifocal reading glasses.
The people who is high astigmatism (larger than 2.50D) . If they wear multifocal glasses, it'll exacerbate the distortion in the peripheral vision and cause dizziness.
The people who is the patients with severe cervical spondylosis, the multifocal glasses is difficult to adapt to head movements.
The people who is impatient or low tolerance is not suitable of multifocal glasses, becasue there's a relatively long period of adaptation for wearing it.
* The differences between bifocal and multifocal reading glasses?
1. Core Differences
Bifocal reading glasses and multifocal reading glasses are both used for presbyopia correction, but there are fundamental differences in their optical design, applicable scenarios and user experience. The main differences between them is as following.
Bifocal
Multifocal
Optical Structure
The bifocal reading glasses have far area and near area, the dividing line separates the these two areas apart.
The multifocal reading glasses have 3 areas including the far area, near area and progressive area. There's no boundary lines to distinguish them.
Vision Field Coverage
Far distance clarity and near distance clarity, no medium distance
Continuous coverage of far distance, medium distance and near distance.
Adaptation Difficulty
It will take about 1-3 days for the switch practice to adapt the bifocal lens.
It will take about 2 to 4 weeks for the head to adapt multifocal lens through practice.
Aesthetic Degree
The bifocal lenses will be printed with the visible age-distinguishing lines.
The sealess and invisible design of multifocal lens means there will be no printed boundaries on the lenses.
Price Range
$55 to $170
$210 to $1,700
2. Optical Design Differences
The divisional design of bifocal reading glasses including upper half part and bottom half part.
Upper Half Part: Far distance area, use base diopter
Bottom Half Part: Near distance area, use base diopter + ADD value
Boundary: Staight cutting or curved cutting
Image Jump: When your line of sight crosses the boundary line, if an object suddenly moves, it can easily cause the dizziness.
The optical design of multifocal reading glasses is that it has no boundary lines, it uses progressive type.
Progressive Channel: From far area to middle area, the degree increases by approximately 0.1D per millimeter.
From middle area to near area, the final ADD value, such as +2.00D
Scattering Area: The inevitable blurry areas on both sides of the lens require coordination with head movement.
3. The different wearing experience between bifocal and multifocal
Situations
Bifocal Performance
Multifocal Performance
Driving
✔ The far area is used for looking at the road, the near area is used for checking the dashboard.
⚠ The middle area will be blurry when looking at the reaview mirror.
✔Seamlessly switch the far area of driving conditions, middle area of rearview mirror and near area of GPS.
Reading
✔The near arear will provide the clear wide field of vision.
⚠The vision field of near area is a bit narrow and the eyes need to turn downward.
Playing Computer
×The vision of middle area will become blurry, need to lower your head to use the near area.
✔The middle area will optimize of vision, the screen is clear within 60 - 80cm.
Go Downstairs
⚠ Lower your head may misuse the near area of bifocal lens, will cause like the steps in the visual field may be distorted.
✔Use the far area for safety when looking straight ahead.
Social Occasions
×The boundary line will expose the area where reading glasses are used.
✔The appearance of multifocal reading glasses is like an ordinary pair of glasses.
4. Target people for bifocal and mutifocal reading glasses
The bifocal reading glasses is suit for the following people:
The people who with limited budget and only have the necessary of switching between seeing far or near distances.
The people who resist the long adaptation period.
The people whose working conditions are simple, such as driver and libratians.
The multifocal reading glasses is suit for the following people:
The people who has multiple distance visual requirements, such as teachers and programmers.
The middle-aged people with presbyopia and pay attention to their appearance.
The people who with healthy cervical vertebrae and cooperate with head movements.
× Neither of the following people is suit of bifocal and multifocal reading glasses
The people who has high astigmatism, usually bigger than 2.50D, wearing the bifocal or multifocal reading glasses will aggravate visual distortion.
The people who has poor vision in one eye, it will be difficult for them to combine the images.
The people who has vestibular dysfunction, the adaptation period of wearing bifocal and mutifocal reading glasses will aggravate the dizziness symptoms.
5. The differences of bifocal and mutifocal reading glasses in fitting parameters
Parameters
Bifocal
Multifocal
Key Data
Bifocal needs pupil distance (PD), ADD value and the height of near area.
Multifocal needs the pupil distance (PD), ADD value, spectacle height and channel length.
Frame Requirements
The height of front frame is higher than or equal to 30mm.
The height of front frame is higher than or equal to 36mm, and the channel integrity.
Customized Precision
±1.0mm tolerance is within the acceptable range.
The multifocal reading glasses requires a 3D positioning instrument, the tolerance is smaller than or equal to 0.5mm.
After a thorough understanding of bifocal and mutifocal reading glasses above, believe you have already figured out which one is more suitable for you better in your mind. It is recommended that when you are choosing the reading glasses, it'll be better for you to refer to the advice of professional opthalmologists or optometrists.
