Bifocals, trifocals, progressives... aren't they all the same? The answer to the question is both yes and no. They all work together to help improve the reading or near vision that typically becomes blurred for most people after they hit their early to mid-40s.
Bifocals & Trifocals
Glasses that have a visible line on them can be either bifocals or trifocals. A bifocal is one that has just one line separating the top part, or the distance area, from the bottom part, also called the reading area. A large disadvantage of bifocals is that there is not an intermediate or mid-range area that will focus on certain distances (I.e. computer distance). A trifocal has two visible lines, as these kinds of glasses allow for not only the distance and near portion of the lens, but also an intermediate part to use as well. The main advantage of having a lined bifocal is that typically there is a larger viewing area for the given distance you are trying to see through. There is also less distortion off to the sides of these lenses, further improving visual ability. However, with a trifocal, the viewing area through each portion of the lens becomes smaller and less "user friendly". Another disadvantage of the lined bifocal/trifocal is that cosmetically, it doesn't necessarily look as appealing as a "no-line" bifocal.
A progressive lens design incorporates the ability to focus on near, far, intermediate and in-between distances. A key advantage to this lens type is that there is no undesired. Few people are aware there are hundreds of progressive optical lens designs, some of which are much better and easier to adapt to than others. Due to the optics of how a progressive lens is designed, there is typically some peripheral lens distortion on lens edges. So, it does take some getting used to, but after several weeks of wearing progressive lenses, most people learn adjusting tricks, such as moving your head to see something on your right or left versus only moving your eyes to the edge of the lens.
Another hurdle is learning to tilt your head down when going down stairs versus looking through the edges of the lenses themselves. Measurements are incredibly important when getting fit for progressive lenses. Even if the numbers are off by 0.25mm, that can throw off the entire viewing area of the lens, making progressive lenses more difficult to adjust to. Ultimately, most people are able to adjust to a progressive lens and can benefit both cosmetically and functionally. You will spend more on a progressive lens design than lined bifocals or trifocals. When comparing different progressive lens designs, patients can expect to pay a higher price for better optical progressive lens quality.
Is LASIK Eye Surgery an Option?
Even though there are no surgical options to mimic a progressive, trifocal or bifocal lens design, the option of monovision (where one eye is set for distance and one eye is set for reading vision) allows numerous patients the ability to live everyday life while reducing dependencies on reading glasses. It is an option that can be accomplished with either contacts or with LASIK eye surgery. However, before deciding to move forward with a LASIK route, it is strongly recommended that you "test drive" it first with contact lenses for one to two weeks in order to ensure your brain can adapt to such drastic visual changes. Even though it is not an ideal solution for everyone, many patients can utilize monovision and enjoy the convenience it brings to their everyday lives.
Learn more about LASIK eye surgery and general eye care via the Providence Eye & Laser Specialist blog: http://www.providenceeye.com/blog/ or contact us today to set up a complimentary LASIK consultation at: http://www.providenceeye.com/contact-us.php - Thank you for reading!