In the market, different types of lenses are available to help protect the vision. Among different types of contact lenses, bifocal and multifocal contacts are popular. These lenses are made to correct the vision for better clarity. In this article, youβll experience the difference between bifocal and multifocal contacts.
What are Bifocals?
Bifocals are a kind of glasses that have two corrections in each lens at the same time. It helps a wearer to see what is nearby and in the distance.
People with conditions can use this, for example, myopia, which is nearsightedness, and hyperopia, which is farsightedness. Astigmatism and presbyopia are caused by aging. They are the most people who are prescribed bifocals or multifocal lenses.
Bifocals is a bi-spectacle that has two different corrective lenses. In the top half of the lens, you will see the inconvenience of the day, that is, the power of your prescription. The power to adjust the reading problems resides on the bottom of the lens. Reading something is like a visual aid that helps you since all you need to do is direct your eyes downwards to get it right.
Analogously to the other contact lens varieties, bifocal contact lenses can be both soft material and rigid gas permeable. For instance, several manufacturers produce bifocal lenses in a disposable format. This means their users need to throw away the lenses once a day or even more often, as they need disposable bifocal contact lenses daily. Before trying any of the contact lenses, it is recommended to consult an eye doctor katy, TX.
Types of Bifocal Contacts
Generally, there are three types of bifocal contact lenses: aspheric, concentric, and translating. Lenses that correct for a given defect are typically classified as such.
- Contact lenses with aspheric design follow their bifocal eyeglass counterparts, where the power parameters are segregated between the contact lenses’ top and bottom. This lens type immediately adapts to the wearer’s need, and a gradual change in lens power lets them see clearly at any distance.
- Contact lenses with annular form consist of two or more rings for vision correction, the central and outer rings. Every ring is enriched with a capability for both vision correction and distance vision curvature.
- Unlike the aspheric contact lens, the translation of contacts is a bi-concave lens with health-related correction on the bottom for near vision and far vision on the top. The bottom edge of the lens should be flat so you’re wearing contact lenses that will not cause rotation when you blink, which is an issue for most contact lens users.
What are Multifocals?
From a mere one correction, multifocal is not limited by a line. These lenses are similar to those of someone who has problems vising far objects wide, objects at a distance, and those at a near distance. Multifocals are produced in the fashion of βprogressiveβ lenses, so the focal point is gradually changed from the top to the bottom of the lens.
Progressive lenses aid in coping with the most frequent vision changes that occur in older age. The presbyopia condition, where one finds it difficult to see/read things near the eyes, is acquired by people over 40. In distance and mid-range vision, multifocal lenses can give you a nice level of comfort, but they are also designed to allow for close vision without strain.
The Mechanism of Multifocal Contact Lenses
Bi-focal and multi-focal contact lenses are designed in different ways, and the lens type depends on its structure. The designs fall into two basic groups:
- Simultaneous vision designs: These multifocal contact lenses have areas of the lens made for viewing far and near. The wearer’s eye shifts the region of the lens that provides the most focused vision, and the type of object being viewed determines the eye’s location. There are two types of simultaneous vision designs: near-sightedness and far-sightedness.
- Segmented designs: These rigid gas-permeable multifocal lenses are designed much like bifocal and trifocal eyeglasses: the center and the top lenses of the lens contain the powers needed for looking at distant objects, and the bottom lenses have the magnifying power for viewing near objects.
The Difference in the Working of Bifocal and Multifocal Lenses
The term bifocal lenses has been coined considering how these lenses are split into two distinct areas with different power magnitudes, which can be used for distance vision in the first and near vision in the second segments. This way, you are able to make a smooth transition between near and far vision. The images will not, therefore, be blurred during the intervention. The word βmultifocal lensesβ can mean any type of lens with more than one power, such as bifocals, trifocals, and progressive. The non-bifocal multifocal lenses have a range of powers that allow you to continuously align your focus for the close and the farther objects and in between.
Multifocal contact lenses are typically designed in one of two ways: as simultaneous vision lenses or as problem-implementing vision lenses.