08-06-2019  (1791 lectures) Categoria: Science

Progressive Multifocal Lens - Presbyopia - Presbicia -Dioptria

Presbyopia is the normal loss of near focusing ability that occurs with age. Most people begin to notice the effects of presbyopia sometime after age 40, when they start having trouble seeing small print clearly — including text messages on their phone.

You can't escape presbyopia, even if you've never had a vision problem before. Even people who are nearsighted will notice that their near vision blurs when they wear their usual eyeglasses or contact lenses to correct distance vision.

The eye's lens stiffens with age, so it is less able to focus when you view something up close.

Researchers estimate that nearly 2 billion people worldwide have presbyopia.

Though presbyopia is a normal change in our eyes as we age, it often is a significant and emotional event because it's a sign of aging that's impossible to ignore and difficult to hide.

In parts of the world where there is no access to vision care, presbyopia is much more than an inconvenience — it's a leading cause of vision impairment that reduces people's quality of life and productivity.

Progressive glasses

  • Not meant for distance or far vision. These are proximity reading glasses (see picture: 3.-reading magazines, 2.-working on your laptop, 1.-conversational distance). Great for outdoor reading.
  • Multi-Focus lenses for multitasking: standard reading distance, computer screen distance (room for keyboard), and MAYBE for conversational distance as well.
  • Progressive multifocal technology, creates 2 gradient-zones for different types of vision, no need to take off without fatigue for long time wearing.
  • High-definition coated resin lenses, 1.56 refractive index for clear vison.
  • Supreme nickel alloy material with ductility and ferromagnetic, highly polished and good corrosion resistance.
  • Degree: 1.00, 1.50, 2.00, 2.50, 3.00; Strength: , +1.0 +1.5, +2.0, +2.5, +3.0
  • Diopter available: +1.00 +1.50 +2.00 +2.50 +3.00 +3.50 +4.00

Classification =>  Magnif. strength-diopter gradient ex.: +3.0 (near sight at bottom) to +1.5 (top)

+1.0 - Down +1.00 - Up +0.50, means: near sight is +1.0 diopter, far sight is +0.50 diopter
+1.5 - Down +1.50 - Up +0.75, means: near sight is +1.5 diopter, far sight is +0.75 diopter
+2.0 - Down +2.00 - Up +1.00, means: near sight is +2.0 diopter, far sight is +1.00 diopter*
+2.5 - Down +2.50 - Up +1.25, means: near sight is +2.5 diopter, far sight is +1.25 diopter
+3.0 - Down +3.00 - Up +1.50, means: near sight is +3.0 diopter, far sight is +1.50 diopter*
+3.5 - Down +2.50 - Up +1.75, means: near sight is +3.5 diopter, far sight is +1.75 diopter 
+4.0 - Down +3.00 - Up +2.00, means: near sight is +4.0 diopter, far sight is +2.00 diopter*

2 GRADIENT ZONES => from +3.0 (near sight at bottom) to +1.5 (monitor sight at TOP)

Introduction of Progressive Multifocal Lens:
A progressive multifocal lens is different from a bifocal lens. There aren't 2 or 3 focus on the lens for near, medium or far vision, but countless gradient focuses. Since the added value increases continuously in the gradient region, the wearer won't need to confirm the strength for medium and far vision, but to obtain a clear vision from the near point to the far point at the appropriate head position (angle respect to the horizontal).

How to wear:
1. In the early wear, follow the principle: From static to move, from indoor to outdoor.
2. First, choose the appropriate scope for far vision, look straight ahead, but not either side.
3. Determine the scope of the near vision, with chin (jaw) pointing up and the eyes down to read the newspaper.
4. Determine the scope of the middle vision, moving the chin slowly down to see through the middle of the transition zone. (or the top if one prefers only 2 regions.. There must be a slow adaptation process).
5. Walk in the room, generally 4-5 days will be enough to adapt yourself.

Item Type: Progressive multifocal presbyopia
Gender: For Unisex
Frame Material: Alloy

Lens Material: Resin
Diopter: 1.00,1.50, 2.00, 2.50, 3.00
Strength: +1.0, +1.5, +2.0, +2.5, +3.0
Size: Shown on the picture. Includes metal spring hinges to prevent the frame from stretching out and falling off your face


What's the pd?: Not sure what pd is???? The glasses are a tad Flimsy but they do the job.
By Suzie on August 4, 2018

Answer: PD are progressive lenses, e.g. the upper part of the lense is for distance and lower part is for upclose like reading. Between those sections the magnifacation progressively changes. Unlinke bi or tri focal lenses there are no lines.

I've lost about $800 worth of prescription glasses overboard over the years. The last time it was only a lens but they could no longer get the lenses for that size frame. I'd worn progressive glasses in the last 2 prescriptions and decided rather than put another $300 into buzzards bay I'd give these a try. I was not disapointed. It's been about 3 years now and I've not even considred purchassing another pair of perscription glasses. As with all progressive glasses it takes a week or two, for your brain-eyes to sync up. After that you won't even think about it anymore. If I put these overboard I'd purchas another set in a blink of an eye.
By Amazon Customer on August 5, 2018

How does one remove the yellow marks?: those silly yellow lines on the glasses. I realize that what they are supposed to do is show the variations. The problem is that that they interfere with the vision. When I saw those lines on the picture of the glasses I thought they were for show on the picture only. The lines are drawn on the glasses and are annoying to remove. I would have given them a 5 because the lenses are well made and they work just great.Use something else that will allow the user to remove those lines and you got a great product.


Answer: You can use alcohol to remove it, wipe it for several times, and it will disappear. :)
By winnerbe Seller on June 26, 2018

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