Vision Over 40
- Dry Eye After Menopause
- How Progressive Lenses Work
- Multifocal Contact Lenses
- Multifocal Eyeglass Lenses
- Occupational Bifocals and Trifocals
Dry Eye After Menopause
Studies show that more than 14% of older Americans have dry eye syndrome, or "dry eye." If you are 50 or older and female, your chance of developing dry eye is even greater. In fact, the American Academy of Ophthalmology says hormonal changes make older women twice as likely as older men to develop dry eye and accompanying symptoms such as eye irritation and blurred vision.
Women who have undergone menopause may experience disrupted chemical signals that help maintain a stable tear film. Resulting inflammation also can lead to decreased tear production and dry eye. Some theories indicate that a decline in a hormone known as androgen could be an underlying cause of dry eye in older women.
What Can You Do if You Are Older and Develop Dry Eye?
While levels of the female hormone estrogen also decrease following menopause, studies have not shown any beneficial effect of estrogen hormone replacement therapy (HRT) in relieving dry eye.
If you are over age 40 and have been diagnosed with dry eye, you may want to avoid laser vision correction surgery. Procedures such as LASIK and PRK can permanently affect nerve function of your eye's clear surface (cornea) and worsen dry eye problems. If you choose to have a refractive surgery consultation, be sure to tell your examining eye doctor about your dry eye condition. Your doctor can perform special tests to determine if your eyes are moist enough for laser vision correction.
If you have already been diagnosed with dry eyes, make sure you are being appropriately treated for other conditions associated with both aging and dry eye, such as rheumatoid arthritis and thyroid autoimmune disease.
Also, keep in mind that many medications commonly prescribed to adults over age 40 may cause or worsen dry eye problems. Examples include diuretics (often prescribed for heart conditions) and antidepressants. If you suspect a medication may be the underlying cause of your dry eye, be sure to discuss this with your doctor. It's possible that changing to a different medical treatment may be equally effective without causing dry eye problems. Also, concurrent treatment of your dry eye may be necessary.
Finally, it's possible that allergies or other problems that cause eye inflammation may be the underlying cause of your dry eye symptoms. Your eye doctor may recommend over-the-counter or prescription eye drops to relieve both your eye allergies and inflammatory dry eye problems.
Article ©2015 Access Media Group LLC. All rights reserved. Reproduction other than for one-time personal use is strictly prohibited.
Multifocal Eyeglass Lenses
Just as eyeglass frames have continually changed to reflect the latest fashions, eyeglass lenses also have evolved. This is particularly true for multifocal lenses - eyeglass lenses with more than one power to help those of us over age 40 deal with the normal, age-related loss of near vision called presbyopia.
History of Multifocal Eyeglass Lenses
Benjamin Franklin, the early American statesman and inventor, is credited with creating the first multifocal eyeglass lenses. Prior to Franklin's invention, anyone with presbyopia had to carry two pairs of eyeglasses - one for seeing distant objects and one for seeing up close.
Sometime around 1780, Franklin cut two lenses in half (one with a distance correction and one with a correction for near) and glued them together, so the top half of the new lens enabled the wearer to see things far away and the bottom half helped them see up close.
This lens, with a line extending across the entire width of it, was first called the Franklin bifocal and later became known as the Executive bifocal.
Modern Multifocal Lenses
The right multifocal lenses for you will depend on your age, your visual needs, your budget and other factors.
Bifocals. There have been many changes to bifocal eyeglass lenses since Franklin's original design, making these two-power lenses thinner, lighter and more attractive. Today, the most popular bifocal for eyeglasses is called a flat-top (FT) or straight-top (ST) design. The part that contains the power for near vision is a D-shaped segment (or "seg") in the lower half of the lens that is rotated 90 degrees so the flat part of the "D" faces upward.
FT or ST bifocals (sometimes called D-seg bifocals) are available in different-sized near segments. The most popular version sold in the United States has a near segment that is 28 millimeters wide and is therefore called the ST-28 (or FT-28 or D-28) bifocal. This design offers a generous field of view for reading, yet keeps the near seg small enough to be cosmetically pleasing.
Other available bifocal designs include lenses with round near segments and bifocals where the near seg extends across the entire width of the lens (Executive bifocals).
All bifocals, however, have a limitation: Though they provide good vision for distance and near, they can leave the wearer's intermediate vision (for distances at arm's length) blurry. Which brings us to…
Trifocals. Trifocal eyeglass lenses have an additional ribbon-shaped lens segment immediately above the near seg for seeing objects in the intermediate zone of vision - approximately 18 to 24 inches away.
This intermediate segment provides 50% of the magnification of the near seg, making it perfect for computer use and for seeing your speedometer and other dashboard gauges when driving.
Trifocals are especially helpful for older presbyopes - those over age 50 - who have less depth of focus than younger presbyopes. (Younger presbyopes may still be able to see objects at arm's length reasonably well through the top part of their bifocals.)
As with bifocals, the most popular trifocals have a flat-top (FT) design, with the near and intermediate segments being 28 mm wide. Trifocals with 35 mm wide segments are also popular.
Limitations of Bifocals and Trifocals
Although bifocals and trifocals are very functional, they pose a problem - the visible lines in the lenses. Most people prefer not to advertise their age by wearing multifocal eyeglass lenses with lines in them that everyone can see.
The lines in bifocals and trifocals cause a vision problem as well. Because they mark well-defined changes in power within the lenses, as the wearer's eyes move past the lines, there is an abrupt change in how objects appear. This "image jump" can be difficult for some wearers to adapt to.
Some years ago, these limitations of conventional bifocals and trifocals led to a major breakthrough in multifocal eyeglass lens design: progressive lenses.
Progressive Multifocal Lenses
Progressive multifocal lenses (also called progressives, progressive addition lenses, and PALs) are true "multi-focal" lenses. Instead of having just two or three powers, progressives gradually change in power from the top to the bottom of the lens, offering a large number of powers for clear vision at all distances - distance, intermediate, near and everywhere in between.
And because there are no visible lines or abrupt changes of lens power in progressive lenses, there is no "image jump," so the wearer's vision generally is more comfortable and seems more natural.
Because of these advantages, progressive lenses have become the most popular multifocal lenses sold in the United States.
Article ©2015 Access Media Group LLC. All rights reserved. Reproduction other than for one-time personal use is strictly prohibited.
Multifocal Contact Lenses
Once we reach our mid-40s, presbyopia - the normal, age-related loss of flexibility of the lens inside our eye - makes it difficult for us to focus on near objects.
In the past, reading glasses were the only option available to contact lens wearers who wanted to read a menu or do other everyday tasks that require good near vision.
Today, a number of multifocal contact lens options are available for you to consider. Multifocal contact lenses offer the best of both worlds: no glasses, along with good near and distance vision.
Types of Multifocal Contact Lenses
Some multifocal contact lenses have a bifocal design with two distinct lens powers - one for your distance vision and one for near. Others have a multifocal design somewhat like progressive eyeglass lenses, with a gradual change in lens power for a natural visual transition from distance to close-up.
Multifocal contacts are available in both soft and rigid gas permeable (RGP or GP) lens materials and are designed for daily wear or extended (overnight) wear. Soft multifocal lenses can be worn comfortably on a part-time basis, so they're great for weekends and other occasions if you prefer not to wear them on an all-day, every day schedule.
For the ultimate in convenience, one-day disposable soft multifocal lenses allow you to discard the lenses at the end of a single day of wear, so there's no hassle with lens care.
In some cases, GP multifocal contact lenses provide sharper vision than soft multifocals. But because of their rigid nature, GP multifocal contacts require some adaptation and are more comfortable if you condition your eyes by wearing the lenses every day.
Hybrid multifocal contacts are an exciting new alternative. These lenses have a GP center and a soft periphery, making it easier to adapt.
Astigmatism? No Problem
All types of multifocal contact lenses - GP, soft, and hybrid - are available to correct astigmatism at the same time as presbyopia.
Monovision
Until you have a contact lens fitting, there's no way to know for sure if you'll be able to adapt successfully to wearing multifocal contact lenses. If multifocal lenses aren't comfortable or don't give you adequate vision, a monovision contact lens fitting may be a good alternative.
Monovision uses your dominant eye for distance vision and the non-dominant eye for near vision. Right-handed people tend to be right-eye dominant, and left-handed folks left-eye dominant. But your eyecare professional will perform testing to make that determination.
Usually, single vision contact lenses are used for monovision. One advantage here is that single vision lenses are less costly to replace, lowering your annual contact lens expenses. But in some cases, better results can be achieved using a single vision lens on the dominant eye for distance vision and a multifocal lens on the other eye for intermediate and near vision. Other times, your eyecare professional may choose a distance-biased multifocal on your dominant eye and a near-biased multifocal on the other eye. These techniques are referred to as "modified monovision" fits.
Article ©2015 Access Media Group LLC. All rights reserved. Reproduction other than for one-time personal use is strictly prohibited.
How Progressive Lenses Work
Progressive addition lenses (also called progressives or PALs) are the most popular multifocal lenses sold in the United States. Sometimes called "no-line bifocals," these line-free multifocals provide a more complete vision solution than bifocals. Instead of having just two lens powers like a bifocal - one for distance vision and one for up close - progressives have a gradual change in power from the top to the bottom of the lens, providing a range of powers for clear vision far away, up close and everywhere in between.
Progressive lenses provide the closest thing to natural vision after the onset of presbyopia - the normal age-related loss of near vision that occurs after age 40. The gradual change of power in progressives allows you to look up to see in the distance, look straight ahead to clearly see your computer or other objects at arm's length, and drop your gaze downward to read and do fine work comfortably close up.
While progressive lenses typically are worn by middle-aged and older adults, a recent study suggests that they may also be able to slow progression of myopia in children whose parents also are nearsighted.
Choosing the Right Frame for Progressive Lenses
Because a progressive lens changes in power from top to bottom, these lenses require frames that have a vertical dimension that is tall enough for all powers to be included in the finished eyewear. If the frame is too small, the distance or near zone of the progressive lens may end up too small for comfortable viewing when the lens is cut to fit into the frame.
To solve this problem and to expand options in frame styles, most progressive lens manufacturers now offer "short corridor" lens designs that fit in smaller frames. Today, an experienced optician can usually find a progressive lens that will work well in nearly any frame you choose.
Different Progressives for Different Purposes
Many different progressive lenses are available on the market today, and each has its own unique design characteristics. There are even progressive lenses designed for specific activities. For example, for the computer user, special "occupational" progressive lenses are available with an extra-wide intermediate zone to maximize comfort when working at the computer for prolonged periods of time. Other designs for office work have a larger reading portion.
Adaptation
It may take a few minutes to a few days before you are completely comfortable with your first pair of progressive lenses, or when you change from one progressive lens design to another. You have to learn how to use the lenses so that you are always looking through the best part of the lens for the distance you are viewing. While you get used to the lenses, you may notice a slight sensation of movement when you quickly move your eyes or your head. But for most wearers, progressive lenses are comfortable right from the start.
Article ©2015 Access Media Group LLC. All rights reserved. Reproduction other than for one-time personal use is strictly prohibited.
Occupational Bifocals and Trifocals
An occupational lens is a type of multifocal that is specifically suited for performing a particular job or hobby. Glasses with these lenses are special-purpose eyewear and are not designed for everyday wear. By strategically placing the near, intermediate and far vision zones on certain areas of the lens, specific visual tasks are made easier.
The Double-D Bifocal: For Reading and Overhead Near Work
The Double-D is an occupational bifocal that consists of a D-shaped flat-top bifocal at the bottom of the lens and an upside-down flat-top near segment located at the top of the lens. The rest of the lens area consists of distance correction.
People in occupations such as auto maintenance and repair can benefit from a Double-D occupational bifocal. This design allows workers to be able to see well up-close, both when looking down and when looking up to work on the undercarriage of a car on a lift. Mail clerks and others who read documents and may need to file them overhead might also find this lens useful at work.
The E-D Trifocal: For When You Need to See Everywhere, but Especially at Arm's Length
The E-D trifocal has the distance correction in the top half of the lens and an intermediate correction for vision at arm's length in the bottom half of the lens. The line separating these two zones extends across the entire width of the lens, like an Executive bifocal. But in the E-D trifocal, a small D-shaped segment for near vision is embedded within the intermediate zone.
The E-D trifocal is an excellent choice for someone who needs a wide field of view at arm's length, but also needs to see clearly close up and in the distance. A television production person, who must keep an eye on several TV monitors while being able to read notes from a clipboard and recognize someone across the room, would be a good candidate for this lens.
Need to Read All Day at Work?
Sometimes, a common multifocal can become an occupational lens simply by changing the position of the intermediate or near segment or the characteristics of the progressive design.
For example, if your job requires you to read most of the day, you may want to consider a separate pair of glasses for work that have the bifocal or trifocal segments placed higher than normal in the lens. This would enable you to read or use your computer for extended periods without having to tip your head back in an uncomfortable posture.
Or you may want to try an "office" progressive lens, which has a larger, wider intermediate zone for computer use and a smaller zone for distance vision. These occupational lenses give you more usable vision for your computer and desk work, yet still provide adequate distance vision for spotting people across the room. However, because the distance zone of occupational progressive lenses is limited, they're not suitable for driving or for other tasks that require a wide field of view in the distance.
What About on the Golf Course?
If you're a golfer and wear multifocal lenses, you know these lenses can be a problem on the course. The near vision zones of bifocal, trifocal and progressive lenses can interfere with your view of the ball, requiring you to tilt your head down in an uncomfortable posture. Everyday multifocals can also make lining up a putt much more difficult.
The solution? Consider trying an occupational multifocal commonly called a "golfer's bifocal." The small (usually round) near segment is placed very low and in the outside corner of just one lens, so it's completely out of the way when you address your ball or line up a putt. But it still gives you enough near vision to read your scorecard or browse a menu for lunch in the clubhouse.
Customized Eyewear Solutions
Nearly all adults - especially anyone over age 40 who needs multifocal lenses - can benefit from having more than one pair of eyeglasses, with the second pair having an occupational design.
Article ©2015 Access Media Group LLC. All rights reserved. Reproduction other than for one-time personal use is strictly prohibited.
