Say Goodbye to Line Bifocals

Line bifocals were famously created by Benjamin Franklin around 1760. His ingenious design has been in use ever since, but over the course of the last two decades new technology has finally brought more options for presbyopes, which are people who have trouble focusing nearby objects. News flash: this happens to everybody, beginning around age 40! You either are a presbyope now or you will be eventually. These new options include no-line bifocal glasses, multifocal contact lenses, multifocal intra-ocular lenses, and monovision LASIK surgery. Although several of these options are limited to a small number of good candidates, almost every person can utilize at least one of these options to finally get out of 250-year-old technology and step into the 21st century.

Progressive Addition Lenses
The most common and universally used replacement for traditional bifocals is the progressive addition lens (PAL), also known as a no-line bifocal or no-line trifocal. The latter two titles are erroneous because, while bifocal means two focal points and trifocal means three focal points, these lenses actually have an infinite number of focal points. They would more accurately be described as no-line multifocal lenses, but in the industry they are called progressives or PALs. In a typical progressive lens the top of the lens is for distance vision and the bottom of the lens is for near vision, just like a traditional bifocal. The difference is that in a progressive lens the focal point of the lens gradually transitions from distance vision to near vision as you look lower and lower through the lens. This has two major advantages. First, it eliminates the line so nobody has to know you are wearing bifocals. Second, it provides an infinite number of focal points so a person theoretically can see clearly at any distance using these lenses as long as they are looking through the correct area in the lens. The two biggest drawbacks of the progressive lenses are the cost, which is typically at least 2 to 3 times that of a line bifocal, and the fact that this lens design creates distortion in the lower corners of the lens.

Multifocal Contact Lenses
The second most frequently used alternative for presbyopes is the multifocal contact lens. Although some people still call them “bifocal contact lenses,” these lenses have more than two focal points so the word bifocal is again inaccurate. When I say “multifocal lens” I mean any type of contact lens fitting that aids presbyopes in seeing both distance and near objects. These multifocal fittings include true multifocal lenses and also “monovision” for those familiar with that term. The three most important things to know about multifocal contacts is 1) very rarely will a multifocal contact lens provide vision as clear as glasses can provide, 2) everybody experiences these lenses differently and so many visits for prescription adjustments may be necessary at first, and 3) most of these lenses require a period of adaptation. The goal of multifocal lenses is to provide acceptable vision for all different distances under normal circumstances with the exception that low-power reading glasses may still be needed for certain activities, such as reading very fine print or when good lighting is not available such as a dark restaurant.

Multifocal Intra-Ocular Lenses
An intra-ocular lens or IOL is a lens that is placed inside the eye. You can think of it like a contact lens on the inside of the eye. These lenses are mainly used to replace a person’s natural lens during cataract surgery. Most multifocal IOLs work in almost exactly the same way that multifocal contact lenses work. A few special IOLs, called “accommodating IOLs,” actually use the body’s natural focusing power. As with multifocal contacts these multifocal IOLs have varying degrees of success, require a period of adaptation, will typically not be quite as clear as glasses, and may still require reading glasses be used from time to time.

Monovision LASIK
The word monovision is used in eye care to mean one eye is focused far away and one eye is focused for near. This is just one of many ways to fit multifocal contact lenses or intraocular lenses, but it is the only way LASIK can be used to provide presbyopes with vision at both distance and near. In this procedure the LASIK is performed as it always is but with one exception – instead of focusing both eyes for distance, only one eye is corrected for distance while the other is set to be nearsighted and therefore able to provide near vision. The drawbacks of this are similar to the drawbacks of multifocal contacts and IOLs, but with any monovision fit another drawback is that depth perception is severely hindered. Most LASIK surgeons perform far fewer monovision surgeries than previously due to an unacceptable number of patients who are dissatisfied with monovision LASIK. Many surgeons today will only perform LASIK on patients who have been wearing monovision contact lenses for a year or more prior to the monovision LASIK surgery. There are additional surgeries that can aid in presbyopia, but they are temporary and the results have been less than expected so I won’t even mention those other options.

As you can see, there are many alternatives to the old line bifocals, but all of these alternatives are full of both pros and cons. To fully understand which of these options is best for your particular visual needs you will need a comprehensive eye health and vision exam and a good conversation with your eye care provider.