Do you suddenly find it difficult to read the label on a bottle of shampoo, an article in a magazine, or a message on your mobile phone? Here Multifocal Contact Lenses can help you, Know How?
You never used to have such trouble, but now you do.
If you are now 40 years or older, it is likely you are suffering from presbyopia and might have to get presbyopia multifocal contact lenses to resolve your sudden-onset vision problem.
Presbyopia: A Refractive Eye Error
Presbyopia is a refractive eye error.
Refractive eye errors are caused by the eye’s inability to refract or bend light correctly. This keeps the light from being precisely focused on the back of the eyes, i.e., the retina. Consequently, someone with a refractive eye error experiences blurry vision.
There are four types of refractive eye errors.
- Myopia or nearsightedness, faraway objects look blurry
- Hyperopia or farsightedness, nearby objects look blurry
- Astigmatism, both faraway and nearby objects can look blurry
- Presbyopia, difficulty focusing or seeing objects that are very near
Refractive eye errors are caused by an irregularity or anomaly in the shape of the eye. It could be caused by the eyeball being too long or too short, the cornea being too conical or too flat, or the lens becoming inflexible with age.
Presbyopia pertains to the last case — namely, when the lens becomes inflexible with age.
What Causes Presbyopia?
When you need to read the messages on your mobile phone, you usually put the phone close to your face. To help you see something so near, the ciliary muscle in your eye contracts, thickening or bulging up the lens to make it more convex or curved.
The lens is the biconvex tissue suspended just behind the iris. Its sole purpose is to help focus the light onto the retina.
The younger you are, the more flexible your lens and ciliary muscle are. In fact, 10-year-old kids can focus and read something that’s just seven centimeters away.
However, the lens and ciliary muscle gradually become less pliable and flexible as you age. Therefore, unlike young children, young adults must hold an object at least 15 centimeters away from their eyes to see it correctly.
It gets only worse from there. Forty-year-olds and sixty-year-olds must hold an object at a distance of at least 22 centimeters and 100 centimeters, respectively, to see it clearly.
In other words, aging is the underlying cause of presbyopia.
Multifocal Contact Lenses for Presbyopia
Like myopia, hyperopia, and astigmatism, one can use eyeglasses and contact lenses for presbyopia. Multifocal contact lenses are one of the most effective strategies for managing presbyopia.
The following are the different types of multifocal contact lenses used to treat the symptoms of presbyopia.
1. Simultaneous Vision Multifocal Contact Lenses
Simultaneous vision multifocal lenses have different zones, each with a predetermined vision power, arranged in a concentric or aspheric pattern.
Concentric Pattern Multifocal Lenses
This type of simultaneous vision multifocal contact lens has specific zones designated for near and distance vision. These distinct zones are arranged in alternating (e.g., distance, near, distance, near, and so on) concentric rings.
There are two types of concentric pattern multifocal lenses: center-distance and center-near lenses.
● Center-Distance Lens
In center-distance lenses, the center viewing zone — the circle at the center of the lens — is designated for viewing objects at a distance.
● Center-Near Lens
The center viewing zone is dedicated to viewing nearby objects in center-near lenses.
One might wear both center-distance and center-near lenses. In this case, the center-distance lens is worn on the dominant eye, while the center-near lens is worn on the non-dominant eye.
Aspheric Pattern Multifocal Lenses
Like concentric pattern multifocal lenses, aspheric pattern multifocal lenses can provide both distance and near vision. However, unlike concentric lenses, aspheric lenses provide vision progression from the center to the periphery instead of designating alternating, discrete, concentric zones for near and distance vision.
In aspheric multifocal lenses, the center has distance vision or near vision. The power then gradually shifts from distance to near vision (or from near to distance vision) the farther it gets from the center of the lens.
2. Segmented Multifocal Contact Lenses
Segmented multifocal lenses, like simultaneous vision multifocal lenses, have designated zones for near and distance vision. However, these zones are arranged vertically rather than in a circular pattern.
Specifically, the upper and central areas of the contact lens are meant for distance vision, while the lower segment of the lens is intended for near vision. A visible line separates the two zones.
In some cases, a segmented multifocal lens can have a zone designated for intermediate vision. When it does, this intermediate vision zone is usually allocated to a thin segment between the distance vision zone in the upper half and the near vision zone in the lower half.
Multifocal Lenses to Correct Presbyopia
Since aging is inevitable, presbyopia is unavoidable. However, you can manage the resulting symptoms and vision problems.
One of the ways to do this is by using presbyopia multifocal contact lenses.