During our 40’s, most people begin to notice that they can no longer see well when performing near tasks. Simple everyday things that they used to enjoy like reading a magazine, viewing a computer monitor or reading or sending a simple text message become increasingly frustrating. Although this problem can be overcome by using reading glasses, in our modern fast paced world where text messages and emails arrive nearly continuously, the need to find a pair of readers to view these important communications is both limiting and annoying. Worse yet, many people associate the need for “readers” with “old age” and the need to dangle readers by a chain around their neck or to retrieve them from a shirt pocket or their purse each time their cell phone vibrates only serves to reminds them that they are getting older. As a group we are much more generally more active than our parents and old fashioned solutions like reading glasses don’t mesh well with our highly technological fast paced world.
This loss of reading ability is called presbyopia (prez-bee-oh-pee-yah) and is an inevitable part of aging. Ultimately, presbyopia affects 100% of the population – including those that had perfect vision before.
What Causes Presbyopia?
Our ability to focus from distance to far is created by the natural lens located inside the eye just behind the iris. When we are young, it acts like a zoom lens or autofocus mechanism on a camera to automatically adjust our focus on those objects we want to see. This focusing is performed using a complex feedback loop involving the brain and retina and is dependent upon impulses from the brain causing tiny muscles in the eye to change the shape of our natural lens. This natural lens is composed of complex crystalline proteins that are both elastic and clear.
As we age, just like other parts of the body that become less flexible, the proteins in the natural lens also age and become stiffer. At first the muscles in the eye involved in focusing work harder, which can offset the rigidity of the lens but this effort may can cause headaches and focus lag when rapidly looking from close to far. Moving the object further away or “getting longer arms” can also temporarily improve the focus as can increasing the ambient light to create more contrast. Eventually, despite these new behaviors, the ability to see objects in our normal working range is no longer possible.
Presbyopia worsens as we age as the lens continues to become more and more inflexible leading to the need for stronger and stronger reading glasses. As a result, the need for reading glasses can progress from only needing them for fine print or low light to needing them throughout the day for any task within arm’s length. If the lens proteins, in addition to becoming more rigid also begin to lose their clarity, the eye is said to have developed a “cataract”. In some sense, the onset of presbyopia is an early form of cataract.
With age the loss of elasticity and flexibility of the natural lens results in an improper focus for near objects and blurred near vision. This condition is called presbyopia.
For many years the ability to deliver a surgical solution for presbyopia remained the Holy Grail of Ophthalmic surgery. That has now radically changed for the better! For people over 40 frustrated by their inability to focus on a cell phone text message or email, read a menu at a restaurant or see a price tag at the supermarket or department store, we have some amazing news! Will Vision and Laser Centers is one of only 30 centers located in the United States selected by the manufacturer to insert the KAMRA® corneal inlay – a revolutionary method of restoring the ability to see near objects for people affected by presbyopia.
Because presbyopia is a loss of the dynamic range of focus that occurs in the aging eye, solutions are not as simple as with nearsightedness, farsightedness or astigmatism that can be readily corrected with laser vision correction. In these situations we are correcting a single focus system. In contrast, glasses, contact lenses or surgeries that create a multifocal optical system are very challenging to deliver.
In order to best understand the paradigm change the KAMRA® corneal inlay represents it is ideal to review the major methods that we can now use to manage this age related loss of ability to focus on near objects. We will then discuss in detail the KAMRA® corneal inlay and how it works to restore near vision.
The oldest and most common way that people compensate for the loss of near vision is with the use of reading glasses. For those that have no need for distance correction, these reading glasses can be purchased without a prescription at a local drug store. If the person is nearsighted, farsighted or has astigmatism they may need special bifocal glasses that may include “progressive” style lenses that provide vision from near-to-far. Although convenient, these progressive lenses are often expensive and also produce a significant amount of optical distortion interfering with depth perception and activities such as sports.
Although they are inexpensive and common place, reading glasses have some disadvantages. First, unlike a corneal inlay, they do nothing to stop the progression of presbyopia. As a result, people need progressively stronger reading glasses as they age.
Also, when a person is wearing reading glasses, their distance vision is blurred. As a result, if it is necessary to view a distance object the glasses must be removed or the person must look “over the top” of the readers. This adaptation, although simple, has the unfortunate effect of making people feel “old”.
In addition, because they are only used intermittently, it is often the case that the glasses are not available when needed. To compensate for this, presbyopic patients frequently accumulate large numbers of these glasses and have then scattered around the house, at work and at play.
Monovision is a solution for presbyopia that has commonly been used by contact lens wearers and, in recent years, it has become a solution also embraced by presbyopes undergoing laser vision correction. With monovision, the person’s correction is modified so that one eye, typically the dominant eye, is corrected for distance vision while the other eye is corrected for near vision.
Amazingly, for most people the brain’s visual processing system is able to alternate attention from distance to near and from near to distance essentially automatically. The brain’s visual system simply alternates which image to pay attention to and does not require any special effort on the part of the individual. Monovision can be a very successful solution for presbyopia for many people and is an important option available to people that dislike reading glasses.
Despite the success of monovision, it does have some disadvantages. The eye that is set for near vision is no longer able to see well at distance. As a result, some patients may notice some distance vision loss in very dim light conditions. This can be easily remedied by prescription glasses for tasks such as driving or watching a movie. Although the latter might be inconvenient, patients find this much better than the incessant need to search for reading glasses just to read an email or check a text message.
Life Style Lasik is a modification of the typical Lasik surgery that creates depth of focus by making the anterior surface of the cornea slightly multifocal. By causing the central portion of the cornea to have a greater power than the periphery, the brain is able to see both distance and near with no side effects like glare or halos.
With Life Style Lasik™ there is no loss of distance vision in either eye so the person retains normal 20/20 distance vision in both eyes, normal binocularity and normal depth perception. As a result, the person can enjoy natural everyday vision with the ability to focus from near to far without the need for reading glasses. After Life Style Lasik™ they are able to see their computer, cell phone text messages, restaurant menu, golf score card and watch without the need for visual aids.
The primary disadvantage of Life Style Lasik compared to the KAMRA™ corneal inlay is that it cannot be performed in all patients as it requires that both eyes have an underlying refractive error such as nearsightedness or farsightedness in order to work satisfactorily. Persons who only need reading glasses and have no problem with distance vision are not candidates for Life Style Lasik™. However, they are typically ideal patients for the KAMRA™ inlay procedure.
The KAMRA™ corneal inlay from AcuFocus® provides a novel solution for presbyopia. As previously noted, Will Vision and Laser Centers is one of only 30 centers in the United States selected by the manufacturer to implant this revolutionary optical advance. The KAMRA® inlay restores every day vision so you can see text messages, a computer screen, the time on your wrist watch and the price on a price tag at the supermarket without the constant frustration of reading glasses or contact lenses. It provides a natural range of vision – from near to far – without blurry zones. In addition, because it does not need to be updated or changed as you age it can help to provide clear near vision over time.
The KAMRA® corneal inlay is an ultrathin aperture made from biocompatible polyvinylidene fluoride and carbon that is surgically placed within the cornea in the non-dominant eye. It is 5 microns thick with an outer 3.8 mm diameter and a central 1.6 mm aperture. The ring has 8400 laser etched holes to facilitate diffusion of aqueous, oxygen and nutrients through the cornea. Once implanted, it provides a full range of vision from near to far by markedly increasing the depth of focus for the eye. The brain combines the distance and near images together and provides a full range of vision. The KAMRA™ inlay can generally be implanted in any patient, including those that have previously undergoing a laser vision correction procedure.
With the KAMRA™, unlike monovision, there is no loss of distance vision in the implanted eye. As a result, the person can enjoy natural everyday vision with the ability to focus from near-to-far. In addition, because the KAMRA™ inlay works by altering the depth of focus of the eye it does not need to have its power adjusted with age. As a result, the KAMRA™ inlay provides the most long lasting vision performance of any presbyopia solution.