If you are over 40, you may have noticed that you are suddenly holding books and other reading material at arm’s length in order to read it. Multifocal contact lenses might be the answer for you. You may be experiencing eyestrain or headaches when trying to focus for length on near objects or computer screens. Or, you may have noticed difficulty when changing focus from a distant object to a near object. These normal symptoms, experienced by many of us in our 40s, are caused by an age-related loss of near focusing ability called presbyopia.

The exact cause of presbyopia is not known however there is strong evidence that presbyopia occurs due to decreased elasticity of the crystalline lens and decreased strength of the ciliary muscles. The ciliary muscles hold the lens in place and when they contract, they increase the tension on the crystalline lens thus increasing its curvature and near focusing power. This is called accommodation and it is required to focus on near objects. As we get older, the ciliary muscles become weaker and the lens becomes less elastic so it is harder for the ciliary muscles to change the shape of the lens and thus it is harder for us to focus on near objects. Our far vision is not similarly affected because when we look at objects far away, the lens and ciliary muscles are in a relaxed position.

Nothing can be done to prevent presbyopia, as it is a normal part of aging, however, there are ways to regain your ability to see near objects. These include wearing reading glasses, bifocals or progressive glasses, or correcting your vision with contact lenses.

Reading glasses are typically worn by patients who don’t need distance prescription lenses; they contain a single-vision lens with a prescription that enables you to see close objects. However, your ability to look at distant objects will be compromised when you are wearing reading glasses and thus you need to repetitively put on and remove your reading glasses in order to see near and far objects. This is often annoying for patients and thus many prefer wearing bifocals and progressive lenses which are able to provide clear vision at all distances. Bifocals and progressives are also needed if you currently require a prescription for distance vision because they are able to correct myopia (nearsightedness) and presbyopia.

However, if you have never had a prescription before, or if you are used to wearing contact lenses, having to wear glasses might be inconvenient for you. Fortunately, there are contact lens options as well.

Monovision is one technique that can be used to correct for presbyopia. Monovision requires wearing contact lenses which correct one eye for near vision and the other eye for distance vision. If your distance vision is clear without a prescription, you would just wear contact lenses to correct near vision in one eye. This technique allows vision to be clear at all distances when both eyes are open; however, it may interfere with depth perception.

Bifocal and multifocal contact lenses are also available. Bifocal contact lenses have two prescriptions in the same lens (like bifocal glasses) while multifocal contact lenses have a range of prescriptions. Bifocal and multifocal contact lenses are available in rigid, gas-permeable lenses (hard contacts) as well as in soft contact lenses.

In the past, bifocal contact lenses often were unsuccessful for many patients; however, new technology in lens design has made these types of lenses much more successful and convenient for patients.

There are 2 basic designs for bifocal and multifocal contact lenses. The first design is the translating lens where the top half of the contact lens is used to see distant objects and the bottom half of the lens is used to see near objects. This type of design typically comes in a hard lens.

The second design is the simultaneous vision lens where your eye looks through both the near and distance powers at the same time but it learns which one to use when looking at different distances. The near and distance powers in this type of lens are distributed alternatively in concentric rings on the lens or they are blended (still concentrically) across the lens (similar to progressive eyeglasses). This type of design is available in both a hard lens as well as a soft contact lens.

Speak to your eye care practitioner to gain more information and to decide whether using contact lenses to manage presbyopia is a good option for you.