How Do Multifocal Contact Lenses Work

Smita Pandit Mar 3, 2019
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Multifocal contact lenses are often recommended for people affected by presbyopia and astigmatism. Have a look at some information about these contact lenses.
Presbyopia is one of the most common eye problems that affects individuals in their mid 40s. This eye condition is characterized by the inability to focus on the nearby objects due to the lens becoming harder and less elastic. In the past, such people had no other option but to use reading glasses.
However, with the new developments in the field of optometry, one has the option of wearing multifocal contact lenses. These contact lenses help in correcting the problem of accommodative insufficiency, as these have more than one focal point.

How Do these Lenses Work

Before contact lenses were introduced, people affected by vision problems were completely dependent on prescription reading glasses. However, many found it hard to participate in outdoor activities with a pair of large prescription glasses resting on their nose.
Contact lenses have certainly made a great deal of difference, and allowed people to enhance their physical appearance, and enjoy certain outdoor activities. For people affected by presbyopia, multifocal contacts help by allowing them to view objects that are near, as well as at a distance.
Due to this reason, these are also referred to as simultaneous vision. These lenses are light and durable. They also have a high water content. Both the near and far vision corrections reaches the retina at the same time, irrespective of the position the eye is in.
The contact lenses with a bifocal design have two separate powers. While one aids near vision, the other helps in distance vision. There is another category of contact lenses with multifocal design. This aids the lens in the transition from distance to close-up vision. These are translating contact lenses. These are similar to bifocal contact lenses.
As the name suggests, the lens is divided into two sections; one section helps one view faraway objects, whereas the other helps one view objects that are nearby. Such contact lenses come in the soft and rigid gas permeable options. The rigid gas permeable lenses use silicone, which is oxygen permeable. This aids in greater eye health and comfort.
These lenses are designed mostly in concentric bifocal pattern; one vision correction is present in the small circle at the center, whereas the other correction is achieved through the outer ring.
The concentric bifocal pattern lenses are categorized into 'simultaneous design' and 'alternating image design'. In case of simultaneous design, the provision for near and far vision is placed in the front of the pupil.
For getting a clearer picture, the brain has to determine which part of the lens must be used. In case of the alternating image design, the bottom part of the lens is for viewing nearby objects, whereas the top portion helps one view the objects that are at a distance.

Pros and Cons

These contact lenses give one the advantage which one didn't have earlier; a spectacle-free vision and excellent near and distance vision as well. No wonder, the reviews have largely been positive. The benefits of using these contacts are numerous.
They are useful for people who have just had a refractive surgery. They are also recommended for people affected by keratoconus, which is a condition wherein the cornea is cone-shaped.
Keratoconus usually causes tremendous vision distortion. Such contact lenses are also prescribed by ophthalmologists for people affected by astigmatism. If the patient feels that soft contact lenses are not providing the desired relief, then the doctor may suggest rigid gas permeable contact lenses.
One needs to regularly wear these contact lenses so that the eye is able to adjust and get used to it. One of the problems associated with these lenses is that these may cause a temporary blur, when removed and replaced by spectacles. One also will need to pay attention to the usual eye care and precautions that contact lens usage requires.
The users need to make sure that their nails are neatly clipped and that the hands are clean while inserting and taking out contact lenses. The extended use could result in eye fatigue due to oxygen and moisture deprivation. In extreme cases, it could also cause dry eyes. 
Some studies do indicate that the long-term use of contact lenses could lead to corneal irregularities in terms of curvature and thickness. The tear film of the eye is also known to be affected by the misuse of contact lenses.
On a concluding note, multifocal contact lenses should only be used under the guidance of a qualified ophthalmologist. There are various brands that are offering such contact lenses, so do make sure that you go through reviews before using them.
Disclaimer: The information provided here is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.
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