Presbyopia and Multifocal Contact Lenses
Do you experience something in your vision or do you know someone who gradually loses the ability to see things clearly up close? That experience is called Presbyopia. Kierstan Boyd (2019) describes it as a normal part of aging. In fact, she said, the term “presbyopia” is a Greek word which literally means “old eye.” She further observed that this experience usually happens after the middle age of forty. One may observe that when they read, they would hold a book or a newspaper or reading a text message on their mobile phone farther away for them to see it clearly.
This is one reality – no one can escape presbyopia. This is true even if you have never had a vision difficulty before. People who are nearsighted will also notice that as they age, their near vision blurs when they use their usual eyeglasses to correct distance vision.
According to some researches, there’s an estimate of 2 billion people worldwide that are experiencing presbyopia. (Bailey, 2019)
One thing is, although presbyopia is a normal adjustment in our eyes as we age, it becomes a significant and emotional happening because it's a signal of aging that's impossible to disregard and hard to hide. If it is not treated or managed, it may lead to vision impairment that may reduce individuals’ quality of life and productivity.
Presbyopia and its Symptoms
When a person becomes presbyopic, common symptoms include:
Headache after doing near-work is one of the most common symptom of Presbyopia.
• Holding smartphone and other objects and reading material farther from your eyes to see them more clearly.
• Moving things farther from the eyes will make them smaller in size
• Presbyopia can also cause headaches, eye strain and visual fatigue that will make reading and other tasks less easy and become more tiring.
Presbyopia and its Causes
Because of the fact that presbyopia is an age-related situation, it is caused by the slow thickening and loss of elasticity of the natural lens inside one’s eye.
Eye specialist say that this changes occur within the proteins in the lens. It makes the lens harder and less elastic over time. It also takes place in the muscle fibers surrounding the lens. Because of the less elasticity, it gets harder for the eyes to concentrate on close objects.
Treating Presbyopia
Presbyopia can be treated with eyeglasses, including reading glasses and sometimes vision surgery. But the good news is, there are also new technology that helps in the treatment of this inevitable situation. Contact lenses specifically to treat presbyopia are already available.
Multifocal and bifocal contact lenses for presbyopia
An example of a Multifocal Contact Lens is Air Optix Aqua Multifocal
Today, numerous kinds of multifocal contact lens options are available for every one experiencing presbyopia. One of them is the multifocal contact lenses. It offer the best of both worlds: no glasses, and along with good near and distance vision.
There are some multifocal contact lenses that have bifocal design with two distinct lens powers — one for your distance vision and one for near. Others have a multifocal design that can be like that of a progressive eyeglasses. It can also be available in both soft and rigid gas permeable lens materials and are designed for daily wear. The good thing is, soft multifocal lenses are designed to be comfortably worn on a temporary basis. Meaning, they are great for weekends and other occasions if you decide not to have them on your daily schedules. (Heiting, 2017)
What’s the difference between Multifocal and Bifocal Contacts?
To simplify their differences, bifocal contacts lenses have only two prescriptions in the one lens. On the other hand, multifocal contact lenses have a variety of powers that is similar to progressive eyeglass lenses in each lens. Multifocal contacts also, is used as a term that describes all contact lenses with several powers or capabilities, including bifocal contacts. (Heiting, 2017)
According to Gary Heiting (2017), there are actually two basic types of multifocal contact lens designs: they are the simultaneous vision designs and the segmented designs.
An example of a Multifocal Contact Lens where the power of the near vision is concentrated at the center, and gradually changes to the prescription for distance as it reaches the periphery.
• Simultaneous Vision Designs. This type of design, the different zones of the lens are selected for far and near vision. It depends on the object being viewed, the wearer's visual system determines the area of the lens that will be responsible for the sharpest vision. And there are two types of simultaneous vision designs: Concentric multifocal contact lenses, which has multifocal contacts that have a primary viewing zone in the center of the lens and surrounded by concentric rings of near and distance powers. Its central viewing zone is for viewing far objects, but center-near designs also are available. The second is aspheric multifocal contact lenses. These multifocal contacts are comparable to concentric multifocal lenses, however as an alternative of having separate rings of distance and near power surrounding the center of the lens, the multifocal lens power slowly changes from distance to near (or sometimes near to distance) from the center to the edge of the lens.
• Segmented Multifocal Designs. The segmented multifocal contact lenses have a design that's comparable to bifocal and trifocal eyeglass lenses. These lenses have an area for distance vision in the upper and central zones of the lens and an area for near vision in the lower half of the lens. They are separated by a visible line in the lenses. This kind of lenses are manufactured with rigid gas permeable contact lens material. They are smaller in diameter than the soft contact lenses. It is sometimes also called translating multifocal contacts or alternating multifocal lenses.
There are lots of information that we can still learn from all of these kinds of contact lenses in treating presbyopia. As to the question what will fit your needs, there is really a necessity to contact and consult your most reliable eye specialist. They will be the one who will determine what specific kind of contact lenses you need for your “old eyes.”
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References
Bailey, G. (2019, April). One Vision Problem You Can't Avoid. Retrieved June 18, 2019, from https://www.allaboutvision.com/conditions/presbyopia.htm
Boyd, K. (2019, February 21). What Is Presbyopia? Retrieved June 18, 2019, from https://www.aao.org/eye-health/diseases/what-is-presbyopia
Heiting, G., OD. (2017, August). Bifocal and Multifocal Contact Lenses. Retrieved June 18, 2019, from https://www.allaboutvision.com/contacts/bifocals.htm
Heiting, G., OD. (2017, September). Multifocal Contact Lenses. Retrieved June 16, 2019, from https://www.allaboutvision.com/over40/multifocalcls.htm
Thompson, V. (n.d.). One Vision Problem You Can't Avoid. Retrieved June 17, 2019, from https://www.allaboutvision.com/conditions/presbyopia.htm
Dr. Mark Paroli is a Licensed Doctor of Optometry in the Philippines who has a special interest in Prosthetic Eye fitting, Low Vision Rehabilitation, Hard and Soft Contact Lenses. He has been fitting custom made Artificial eyes in the Philippines for more than ten years.
markparoli@artificialeye.ph