Bifocal Contacts from The River’s Edge Optical
One of the fastest growing segments of our contact lens practice is the prescribing and designing of contact lenses for patients over 40 who are developing presbyopia.
Holding menus, newspapers and other reading materials farther from your eyes, in order to see clearly, is the primary sign of developing presbyopia. (Presbyopia is an eye condition caused by aging that results in the loss of the ability to focus on near objects. It normally begins developing in our early forties and progresses up into our mid- sixties, resulting in gradual loss of focusing abilities, requiring periodic adjustments to prescriptions in order to see clearly at near). When you have contact lenses in your eyes and your vision is normal when looking far away, but more difficult closer to your eyes, this is due to a loss in focusing ability primarily caused by aging. Patients who wear contacts will feel the presbyopia change sooner when wearing their contacts verses glasses. Bifocal and multifocal contact lenses are specially designed to provide good vision at all distances for people who do not wish to wear reading glasses over their contacts.
Bifocal contact lenses are manufactured in soft plastics, rigid gas permeable materials or in new hybrid designs that combine soft and rigid gas permeable characteristics (i.e. Duette Synergeyes Multifocal Contacts). Some can be worn on a frequent replacement schedule or disposable plan.
Most lens manufacturers today offer multifocal contact lenses made of silicone hydrogel material. These lenses allow significantly more oxygen to reach the cornea than conventional soft lenses for greater wearing comfort. They are available for both daily wear and extended wear.
At The River’s Edge Optical we primarily use combinations of the following name brands to find the best option for each patient: Acuvue Oasys for Presbyopia (Vistakon), Air Optix Aqua Multifocal (Ciba Vision), Biofinity Multifocal (CooperVision) and PureVision Multi-Focal (Bausch + Lomb). Special Hybrid design is Duette Multifocal.
Bifocal Contacts, Multifocal Contacts – What’s the Difference?
Bifocal contacts lenses have two prescriptions in the same lens. Multifocal contact lenses have a range of powers (similar to progressive spectacle lenses) in each lens.
“Multifocal contacts” is also used as a catch-all term for all contact lenses with more than one power, including bifocal contacts.
How Multifocal Contact Lenses Work
Bifocal and multifocal contact lenses work in several different ways depending on the design of the lens. The designs fall into two basic groups:
- “Alternating vision” (translating) lenses are so named because your pupil alternates between the two powers as your gaze shifts upward or downward.
- “Simultaneous vision” lenses require your eye to be looking through both distance and near powers at the same time. Although this might sound unworkable, your visual system learns to select the correct power choice depending on how close or far you’re trying to see. Simultaneous vision lenses come in two types: concentric ring designs and aspheric designs.
Left: In this example of a translating design, the near power is on the bottom. The bottom edge is flattened to keep the lens from rotating on your eye when you blink.
Middle: In this concentric design, the distance prescription is in the center and is surrounded by rings of near and far power, but near-center versions also are available.
Right: In this aspheric design, the near and distance prescriptions are both in front of the pupil.
Alternating Bifocal Contact Lenses
Alternating, or translating, bifocals work much like bifocal eyeglasses. They have two power segments with an obvious line of separation between the distance correction on top and the near correction below. Your eye looks through either one or the other, depending on whether you’re looking far or near.
With bifocal eyeglasses, this mechanism works because the lenses stay in place even as your eye moves. That can happen with contact lenses, too. Since most alternating bifocals are gas permeable (GP) lenses, they are smaller in diameter than soft lenses and they ride on your eye above your lower eyelid. Therefore, when your gaze shifts downward, the lens stays in place allowing you to see through the lower, near-correction part of the lens.
Concentric Ring Designs
This type of bifocal contact lens features a prescription in the center and one or more rings of power surrounding it. If there are multiple rings, they alternate between near and distance.
Typically, at least two rings are within your pupil area, but this varies as your pupil expands and contracts due to varying light.
Concentric ring bifocal contact lenses can be made of either soft or rigid (GP) material. The locations of the powers will vary:
- GP bifocals usually have the distance power in the center (called center-distance).
- Soft bifocal contact lenses usually have the near power in the center (center-near).
- Some soft multifocal designs are center-near on your dominant eye, but center-distance on your non-dominant eye.
Aspheric Multifocal Contact Lenses
These multifocal contact lens designs work more like progressive eyeglass lenses where the different prescriptive powers are blended across the lens. However, unlike eyeglasses, aspheric contact lenses are simultaneous vision lenses, so your visual system must learn to select the proper prescription for the moment.
This is the only type of multifocal contact lens that can be described as “progressive.” It’s also concentric, like the concentric ring designs, and it has become the most popular type of multifocal contact lens.
Will Bifocal Contact Lenses Work for Me?
Today new technology has produced successful designs, as well as, a greater variety of designs. Almost all patients today have the option of wearing a multifocal contact regardless of prescription.
Your doctor may also try these related techniques:
- Monovision: involves using single-vision lenses to put your near prescription on one eye and your distance prescription on the other.
- Modified monovision: uses a single-vision lens on one eye and a multifocal lens on the other.
Which Bifocal Contact Lens is Right for Me?
Success wearing multifocal contacts is often dependent upon the knowledge and experience of the eye doctor. Dr. Ferguson (Dunes Eye Consultants) successfully manages hundreds of multifocal contact lens wearers annually. The secret to success lies in the ability to customize a solution for each patient by using all available multifocal contact lens technologies. There is no perfect template. However, patients with a healthy ocular surface and normal tear chemistry can successfully wear multifocal contact lenses regardless of prescription. So the answer to the question, “Are bifocal contact lenses right for me?” is yes! This is assuming ocular health is normal and multifocal contact lenses are indicated for your level of vision correction. An important thing to understand and keep in mind is that many multifocal contact lens wearers managed by Dr. Ferguson require treatment of their dry eye in order to maximize performance of the lens and wear the lens comfortably throughout the day.
Of course the studies have shown that multifocal contact lenses are the preferred choice for presbyopia versus monovision. However, Dr. Ferguson still employs monovision contact lens correction for many patients. Monovision can be a less expensive option for patients wanting to reduce their dependency on reading glasses as a contact lens wearer. Some patients even prefer having balanced distance vision in both eyes and wear reading glasses over their contact lenses, but this is less and less common for patients today because they know that the contact lens technology in multifocal contact lenses have improved so much.
Monovision will always be a contact lens option for presbyopes, but advancements in contact lens technology make this option a secondary one in today’s modern contact lens practice. Studies directly comparing monovision to both soft (Benjamin, 2007; Richdale et al, 2006; and Situ et al, 2003) and GP (Johnson et al, 2000) multifocal contact lenses have shown that multifocal contact lenses are preferred by 68 to 76 percent of wearers. Additionally, when the visual performance of four different presbyopic lens corrections (i.e., progressive addition spectacles [PALs], a GP multifocal lens design, a soft bifocal lens design, and monovision) were compared—including high and low contrast acuity and contrast sensitivity function—the GP multifocals were found to be similar to PALs, followed by the soft bifocals, with monovision finishing last in all categories tested (Ragagopalan et al, 2006).
What is particularly important for presbyopes is how they see in “real-world” situations. Woods et al (2009) compared monovision to a soft multifocal contact lens (Air Optix Aqua Multifocal, Alcon) in emerging presbyopes. Specifically, via the use of Blackberry technology, subjects rated their quality of vision in a variety of real-world situations—including daytime and nighttime driving and watching television—in addition to routine clinical testing. Whereas monovision performed better for examination room vision testing, the soft multifocal lens was clearly preferred in the real-world situations.
Fees and costs for Bifocal/Multifocal Contact lenses?
The fees for professional services and materials for multifocal contact lenses require a greater investment than standard contact lens options. Noticeably, the design of the lens is more complex, as well as the knowledge and understanding to help the patient find the correct solution. The range of fees including professional service fees and materials can range from $300.00 to $1,200.00 depending upon the complexity of the multifocal contact lens design. Whether a patient has simple nearsightedness and presbyopia and can use just a standard soft multifocal lens design or whether they require multifocal contact lens correction because they have had previous corneal surgeries, transplants or other medical eye surface conditions, the complexity of the case dictates what materials are used and the knowledge required to make a successful solution.
Initially, the most important first step is to get a comprehensive vision medical assessment. Areas that need to be addressed are: what is the level of correction for distance, what is the tear chemistry and ocular surface health and is there any degree of early cataract formation that may be present? In addition, retinal health is very critical in knowing what the overall optics are for the patient. Once the comprehensive vision and health nature of the patient is understood, then appropriate recommendations can be made.
Diagnostic lenses have to be used in order to successfully find the proper solution for the patient. At Dunes Eye Consultants and The River’s Edge Optical, we have all soft multifocal contact lens options in stock to allow for an efficient diagnostic experience when the patient comes to our office. In addition, we have multiple fitting sets for specialized lenses including the Duette multifocal high definition and multifocal hybrid lenses and the scleral medically necessary contact lenses. Standard soft multifocal lens designs are the least costly for the patient and the easiest to diagnose and fit.
It is important to understand that if you carry vision insurance, most vision plans offer some benefits for contact lenses that is a defined amount. This amount typically does not cover the entire amount of the multifocal contact lens package, but certainly can help reduce cost on an annual basis. If you require medically necessary contact lenses, often times this is covered in full through vision plans and medical insurance (Vision Medical Services). If you wish to experience the freedom from wearing multifocal glasses and wish to find out if contact lenses are the correct option for you, please contact Dunes Eye Consultants at 605-232-6900 and schedule an appointment for an evaluation.
We are the region’s most experienced contact specialists!
For more information about multifocal contact lenses, visit with one of our opticians at The River’s Edge Optical or make an appointment for an evaluation at Dunes Eye Consultants with Dr. Ferguson.