In this blog post, we will address the question many of us have as we age: what is the difference between progressive and bifocal lenses in glasses? In order to understand the difference between bifocals versus progressive glasses, when must first understand the developmental milestones in our eyes as we age.
- Age Birth-18
- Eyes develop.
- Age 19-45
- Prescription stable. Lens is flexible.
- Age 46-65
- Prescription stable. Lens is inflexible.
- Age 66+
- Prescription may shift as lens becomes cloudy.
Milestone 1: Birth to Age 18
The 1st milestone is called ocular maturity and occurs between birth and 18 years of age. The development of our eyes from birth is rapid and intense. A newborn baby actually has about 20/200 vision, but that vision rapidly improves as he or she starts seeing our beautiful world. Most babies start out somewhat farsighted, but they have very flexible lenses in their eyes and therefore can use the focusing power to improve their vision. As we age, the refractive error shifts progressively nearsighted. A person who develops nearsightedness will generally develop more severe nearsightedness, if their eyes start to become nearsighted when they are very young. The typical timeframe for the appearance of myopia (nearsightedness) is between age 7 and 12. Generally, if you don’t wear glasses until you’re in your later teenage years, you will not develop severe nearsightedness. By about age 18, our eyes become largely stable in the refractive error. As a refractive surgeon, we measure the refractive error (glasses prescription) over the lifetimes of our patients. There may be very slight shifts toward nearsightedness between age 20 and age 50, but usually it is not large amounts of change.
Milestone 2: Age 19-45
Milestone 2 occurs between age 19 and 45. In this phase of our lives, we generally have fairly stable glasses prescription, although it may change slightly as we get new glasses or contact lenses. We have a very flexible lens in our young adulthood that allows us to focus on near objects, because the lens of our eyes is very flexible! The exception to this is someone who is farsighted and needs reading glasses, or even distance glasses with or without a progressive lens vs. bifocal lens. This is a great age to have LASIK, PRK, or ICL depending on your refractive error, anatomy, and hobbies/vocation.
Milestone 3: Age 46-65
Milestone 3 is sometimes called lens dysfunction. The lenses of our eyes get less flexible in our mid 40s and then less clear in our mid 60s (when we develop cataracts). The lack of flexibility in our eyes after age 45 makes it so that we cannot have perfect distance vision and near vision in both eyes. It’s at this stage of our lives that we must discuss whether you prefer progressive lenses versus bifocals and the difference between bifocal and progressive lenses.
The spectacle correction (glasses) of our nearsightedness, farsightedness, and/or astigmatism generally corrects our vision for seeing distant objects clearly. When this occurs, then we must use muscles in our eyes to flex the natural crystalline lens of our eyes. This lens is located behind the iris and is generally invisible unless someone has a significant cataract. The lens becomes less flexible and therefore the eye is focused wherever the glasses focus and we must have either no line bifocals or progressive lenses to allow us to see near objects. The difference between bifocals and progressive lenses is fairly simple. Bifocal lenses generally have a line separating the distance lens from the near lens. The difference between bifocals and progressive lenses is that it is much easier for someone to adapt to glasses that do not have a line that can distract the glasses wearer. We really do not see bifocal glasses much anymore. The technology to create progressive lenses allows a gradual increase in the focusing power of the glasses as we look further down the lens. This makes it much more tolerable. Many of our patients don’t even realize that they’re wearing progressive lens versus bifocal wearers who always know when they’re looking through the bifocal segment of their glasses. With progressive lenses, images are clear depending on what part of the lens we are looking through with our glasses.
The difference between progressive and bifocal lenses is generally a greater level of technology in progressives that allows you to see distance and near objects with a gradual progression of focusing power as you look further down the lens in one pair of glasses.
Sometimes people will get several pairs of glasses that focus images at near for computer or for very near for objects such as splinters. One may have glasses for distance only, which is good for someone who spends a lot of time driving or looking far away. Either progressive or bifocal lenses may be distracting to someone whose time is spent outdoors using their eyes for distant tasks.
Refractive Lens Exchange (RLE)
A technology that expands upon our already extensive experience with cataract surgery is called refractive lens exchange. With RLE technology, we remove the natural lens of your eye and replace it with an artificial multifocal toric intraocular lens. This technology allows you to experience clear uncorrected vision with a customized lens for your eye that allows you to see both distance, near, and some intermediate vision without any glasses. Whether you are nearsighted, farsighted, or have astigmatism, these technologies allow you to have potentially perfect distance and mirror vision with no glasses. AND… you won’t need cataract surgery when you’re older and develop gradually declining vision. It’s pretty cool!
Although the difference between progressive and bifocal lenses is a result of improving technology, they both may be used much less frequently as we perform more RLE procedures: multifocal intraocular lenses that allow people to have their dysfunctional natural lens removed, and an artificial lens implanted to replace the defective/dysfunctional natural lens of our eyes.
Milestone 4: Age 66+
As we age, the lenses of our eyes become less flexible, as I described above in milestone 3. In our 50s, 60s, and 70s, the lenses of our eyes become less clear. Vision gradually declines, with most people experiencing some reluctance to drive at night because of decreased contrast sensitivity, glare, and halos. At some point in the spectrum, we decide to have cataract surgery. Insurance companies decide for us when we are allowed to have it if we want them to pay for it. Cataract surgery is extremely successful. It is the most commonly performed Medicare procedure in the United States with over 4 million procedures annually. Medicare does not cover the fees for the multifocal lenses however. In my estimation, we can gain a much higher quality of life by having the lens of our eyes removed when it first becomes dysfunctional in our later 40s. This way we don’t have to wait for declining vision and difficulty seeing at night.
Why wait until you’re in your 70s to have insurance pay for an ever-decreasing portion of the cost of lens replacement surgery? You can have it all much sooner and enjoy life without glasses or contacts and not need cataract surgery when you’re much older. RLE is just taking care of the problem earlier.
Call us at 425-451-2020, or schedule online at sharpe-vision.com for your free comprehensive evaluation. We look forward to seeing you soon!