PresbyopiaHaving trouble reading the daily newspaper?  Or looking at your computer screen?  You may have presbyopia.

Presbyopia is a condition in which the eye displays a progressively reduced ability to focus on near objects. The condition is most seen with people as they age, often over the age of 40.  Although presbyopia’s exact mechanisms are not fully understood, some research supports a loss of elasticity of the crystalline lens.

People who suffer from presbyopia often turn to over-the-counter reading glasses to help with seeing near objects.  These work well for most people.  For those who want another solution, laser eye surgery may help.  A surgical technique offered is to create a “reading eye” and a “distance vision eye” may help. This process involves a surgical technique commonly used in contact lens practice, known as monovision.

For more information about presbyopia and/or treatment with laser eye surgery, please call Premium Vision Surgical Centres in Cornwall to schedule an eye exam.

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What Is Presbyopia/dysfunctional lens syndrome (DLS)?

Presbyopia (which literally means “aging eye”) is an age-related eye condition that makes it more difficult to see very close. When you are young, the lens in your eye is soft and flexible. The lens of the eye changes its shape easily, allowing you to focus on objects both close and far away. After the age of 40, the lens becomes more rigid. Because the lens can’t change shape as easily as it once did, it is more difficult to read at close range. This normal condition is called presbyopia or dysfunctional lens syndrome (DLS).


Dysfunctional Lens Syndrome with Dysfunctional Lens Replacement

Frustrated with Dysfunctional Lens Syndrome

The bad news about dysfunctional lens syndrome (DLS) is that you already have it.  Everyone suffers the progressive effects of DLS.  It starts almost the moment you are born and progresses relentlessly everyday you live until you have your lens dysfunction repaired.

What is Dysfunctional Lens Syndrome?

DLS is the progressive loss of function of the natural lenses inside your eye.  The lens is clear and flexible when you are born.  The clarity of this vital part of your eye allows light to pass cleanly through without light scatter, glare, or blurry vision.  It’s flexibility allows it to change shape and focus so you can see both far and near objects. From the day you were born, your lens started to lose both its clarity and its flexibility.  The early losses go largely unnoticed.

Dysfunctional Lens Syndrome graph

Dysfunctional Lens Syndrome Stage 1

In stage one of DLS the loss of flexibility causes you to loose your ability to focus on close objects.  The ability to focus on close objects is called accommodation.  A one year old can literally focus clearly on an object immediately in front of his/her eye.  By two years of age, an infant can no longer focus that close and would you would have to move an object a bit further out before it would be in focus again.

This deterioration continues at a steady pace, but most don’t notice it at all until around age 40 when they start having trouble focusing at 14-16 inches from their eye, which is where we hold a book.  At first you can move the book further away and still read, but in the end, you have to add magnification to make the letters large enough to read.

visual accommodation graphic

Why do we Lose Accommodation?

To explain lens dysfunction it is helpful to first describe a fully functioning lens. Healthy lenses are rounded.  This makes it magnify objects so they look larger.  It works like the magnifying glass you may have played with as a youngster or a strong pair of reading glasses.

Lenses are held in place by a series of small fibers called zonules.  These zonules are connected to a small muscle called the ciliary body.  When the muscle is relaxed, the zonules are under tension.  This stretches the lens making it flat instead of round.  The flatter shape makes objects in the distance in focus.

When the ciliary body muscle flexes, it relieves the tension on the zonules.  This allows it to spring back to its natural rounded shape, making it like a magnifying glass so you can see objects up close.

As you age, lenses lose their elasticity so that they don’t spring back to as round a shape as they did when you were younger.  They no longer can magnify enough to see up close.  Reading glasses are needed to make up for the loss of accommodation.

HD Analyzer, Dysfunctional Lens Syndrome, Colorado Cataract Surgeons, dysfunctional lens replacement, dls

Dysfunctional Lens Syndrome Stage 2

In Stage 2 of DLS you have the loss of focusing ability from stage 1 plus the proteins that make up the lens become discolored enough to cause mild glare and visual blur.

These proteins start out completely clear.  They allow light to pass through without being scattered.  As we age, the proteins denature, turning from clear to a yellow color.

To understand the process of denaturing proteins, consider egg whites.  They made up of clear proteins.  As the egg whites are heated up, the proteins denature and turn white.

In a similar fashion, as the proteins slowly denature throughout life, they change from clear to a yellow color causing blurry vision and glare with night driving.

The HD analyzer is a test we use to determine how much light scatter you are experiencing.  It projects a beam of light to the back of your eye.  The beam reflects off the back of your eye back into the HD analyzer where it measures how much the beam has been scattered by your eye.

Dysfunctional Lens Syndrome Stage 3

In stage three of DLS, you lose the rest of your ability to focus and the yellowing of the lenses becomes dark enough that we call it a cataract.  If left untreated, the cataract will turn dark brown.  It would be like trying to look through a dark brown bottle.  Glare would be horrible, it would be difficult to recognize signs until you were right next to them, and reading would become challenging.  Ultimately, this turns completely white and you would be blind, only able to see light.

Dysfunctional Lens Replacement

The good news about DLS is that there is a cure: dysfunctional lens replacement.  This involves removing the dysfunctioning lens and replacing it with a plastic intraocular lens implant.  The new intraocular lens is clear, restoring clarity of light transmission.  Advanced technology intraocular lens implants can be toric (astigmatism correcting) or they can be a multifocal or accommodating implants to restore some focusing ability.  Many patients with mulifocus  or accommodating implants do not need glasses for near or far vision after the surgery.  While these implants are not perfect, they are spectacular.  The ability to correct many of the ravages of DLS dysfunctional lens replacement is one of the marvels of modern medicine.

Dysfunctional Lens Replacement Costs

Dysfunctional lens replacement costs depend on which stage you choose to have the surgery and the level of advanced technology you choose to employ.

Once the faulty lens is removed, it never grows back.  You only have to have it removed once.  Those that choose to have it replaced in stage 1 or early stage 2 to improve focusing ability and visual quality never have to go through the progressive glare and blurry vision of late stage 2 or stage 3 DLS.  The procedure goes by various names such as clear lens extraction, or refractive lens exchange (RLE).  At this stage the repair procedure would be considered elective so insurance would not help pay for the replacement.

If you wait until late stage 2 or certainly by stage three, the lens would officially be labeled a cataract and the replacement would be called cataract surgery.  At this level, the standard replacement costs would be considered medically necessary and insurance would cover the basic parts of the cataract surgery costs.

The procedure to remove a lens in stage 1 is pretty much identical to removal in stage 2 or 3 except that the stage 1 lenses are soft like jello and the stage 3 are hard and brittle like toffee.

If you elect to have image guided, laser cataract surgery with an advanced technology intraocular lens implant to help correct astigmatism or restore some focusing ability then insurance would cover the medically necessary parts of the surgery depending on deductables and you would pay some amount for the additional elective services.

Everyone blessed with long life should eventually have their DLS repaired.  Cataract Surgery is the most common surgery performed in the world because everyone has it done twice, once for each eye.  The question is, “At which stage of of lens dysfunction do you choose to have it repaired?”

If you have additional questions about DLS, please schedule a time to meet with me or post a comment.

Gary Foster, M.D.

Since nearly everyone develops presbyopia, if a person also has myopia (nearsightedness), hyperopia (farsightedness) or astigmatism, the conditions will combine. People with myopia may have fewer problems with presbyopia, as they can take off the glasses and read.


Some of the signs and symptoms of presbyopia include eyestrain, headaches or feeling tired from doing up-close work. One of the most obvious signs of presbyopia is the need to hold reading materials at arm’s length in order to focus properly. The symptoms of hyperopia (farsightedness) and presbyopia are similar, however, they are caused by different things. Hyperopia is a refractive error that occurs when the eye is shorter than normal or has a cornea (clear front window of the eye) that is too flat. As a result, light rays focus beyond the retina instead of on it. Generally, this allows you to see distant objects clearly but near objects will appear blurred. While hyperopia is usually present from birth, presbyopia develops later — usually around age 40.


Your eye doctor can diagnose presbyopia as part of a comprehensive eye examination. In addition to checking for other eye problems, he or she will determine your degree of presbyopia by using a standard vision test Your doctor will use a phoropter, an instrument that the measures the amount of refractive error you have and helps determine the proper prescription to correct it. You will try out several corrective prescriptions to determine which one will offer the best presbyopia correction for you. He or she can also discuss presbyopia surgery as another method for treating your presbyopia symptoms.




There is no best method for correcting presbyopia. The most appropriate correction for you depends on your eyes and your lifestyle. You should discuss your lifestyle with your ophthalmologist to decide which correction may be most effective for you

Reading glasses are a very common and easy way to correct presbyopia symptoms, and are typically worn just during close work such as reading, sewing, etc. These “readers” are easily purchased at drug stores and other retail stores. You can also choose higher-quality versions prescribed by your eye doctor. If you decide to pick out a pair of reading glasses from the store, it is important that you select the weakest pair that will allow you to read newspaper-size print without difficulty. If you wear contact lenses, your eye doctor can prescribe reading glasses that can be worn with your regular contacts to help you adjust to detailed, close-up work.

Eyeglasses with bifocal or progressive lenses are another common method of correcting presbyopia. Bifocal lenses have two different points of focus. The upper part of the eyeglass lens is set for distance vision, while the lower portion of the lens has a prescription set for seeing close work. Progressive lenses are similar to bifocal lenses, but they offer a more gradual visual transition between the two prescriptions, with no visible line between them.

Another option for correcting presbyopic vision is multifocal contact lenses. Just as bifocal lenses have two levels of corrective power, multifocal contact lenses create multiple levels of corrective power.

Another way to correct presbyopia with contact lenses is monovision, in which one eye has a contact set for distance, and the other has a contact set for near vision. The brain learns to adapt to using one eye or the other for different tasks.

Because the eye’s lens continually changes with age, you will need to have your prescription increased over time as well. Your eye doctor can prescribe a stronger prescription as needed to help you with up-close vision.

Surgical options

There are surgical options to treat presbyopia. One is called conductive keratoplasty or CK. With this procedure, radio waves are used to create more curvature in the cornea and improve near vision. CK can treat presbyopia effectively, but the correction is temporary and diminishes over time.

LASIK can be used to create monovision, in which one eye is corrected for near vision while the other eye is set for distance vision. Another LASIK procedure — which is undergoing clinical trials in the U.S. — is presbyLASIK. This procedure uses an excimer laser to sculpt multifocal zones directly on the cornea, enabling vision at multiple distances.

Also, there is a procedure known as refractive lens exchange. This refractive surgery technique replaces your eye’s rigid natural lens with an artificial lens that corrects presbyopia symptoms, providing multifocal vision

The most advanced surgical option is Clear Lens Extraction with Multifocal or accommodative lenses

Clear Lens Extraction is an excellent option for those individuals wishing to decrease their dependence on both distance and reading glasses. Clear Lens Extraction offers an opportunity to safely intervene in what would otherwise be a lifelong commitment to reading glasses. In this painless procedure, the natural lens inside your eye is removed through a tiny, self-sealing incision. A Multifocal intraocular lens is then carefully implanted in the eye, unfolded, and properly positioned by your doctor. The ReSTOR or the Multifocal Tecnis are multifocal lenses, meaning that they have the potential to provide good distance, intermediate, and near vision with less dependence on reading glasses. The most advanced lens option is the extended range Tecnis Symfony IOL.

Ideal candidates for Clear Lens Extraction and Multifocal implantation are: Hyperopic (farsighted) in a range too high for laser vision correction. Good candidates for laser vision correction who desire less dependence on both distance and near corrective lenses.

The evaluation for Clear Lens Extraction is very similar to that for laser vision correction, but the procedures are different. While LASIK and PRK are performed on the cornea (outside of the eye), Clear Lens Extraction involves surgery inside the eye. If you are a candidate for Clear Lens Extraction, your doctor will outline realistic expectations as well as thoroughly review with you the procedure’s risks, benefits, and alternatives. The Alcon Multifocal IOLs are an alternative for individuals seeking less dependence on both distance and reading glasses. It is implanted inside the eye after the natural lens has been removed, and can often provide good uncorrected vision at distance, intermediate, and near.

In the multifocal type, a series of focal zones or rings is designed into the IOL. Depending on where incoming light focuses through the zones, the person may be able to see both near and distant objects clearly.

The design of the accommodative lens allows certain eye muscles to move the IOL forward and backward, changing the focus much as it would with a natural lens, allowing near and distance vision.

The ability to read and perform other tasks without glasses varies from person to person but is generally best when multifocal or accommodative IOLs are placed in both eyes. It usually takes 6 to 12 weeks after surgery on the second eye for the brain to adapt and vision improvement to be complete with either of these IOL types.

Considerations with multifocal or accommodative IOLs

For many people, these IOL types reduce but do not eliminate the need for glasses or contact lenses. For example, a person can read without glasses, but the words appear less clear than with glasses. Each person’s success with these IOLs may depend on the size of his/her pupils and other eye health factors. People with astigmatism can ask their Eye M.D. about toric IOLs and related treatments. Side effects such as glare or halos around lights, or decreased sharpness of vision (contrast sensitivity) may occur, especially at night or in dim light. Most people adapt to and are not bothered by these effects, but those who frequently drive at night or need to focus on close-up work may be more satisfied with monofocal IOLs.

Other Options


Extended Range Lens Implant


Simulation of vision through different stages from normal to DLS1(presbyopia) to DLS2 then DLS3/cataract. Then correction of cataract with different types of lens implants