MULTIFOCAL EYEGLASS LENSES
Multifocal lenses technically refer to any lens that provides more than one zone of corrective power and would therefore include bifocal, trifocal and progressive lenses. Multifocals are designed for the many individuals over 40 who struggle with presbyopia – the age-related near vision loss that requires us to use eyeglasses for reading and focusing on objects in our near vision. The multiple lens powers enable you to correct for near and distance vision with one pair of glasses.
Bifocal lenses are divided into two powers, one for distance vision and the second for near vision. Bifocals are created in a variety of designs with different sized and shaped viewing segments for near and far vision. While bifocals provide good distance and near vision, they are lacking in corrective power for intermediate areas, which is what has led to the development of trifocal and progressive lenses.
Trifocal lenses provide an additional lens power zone for intermediate vision (which is typically about an arm’s length away).
Some people are bothered by the visible lines where the lenses are divided in bifocal and trifocal lenses. In addition to aesthetics (the lines have become a sign of presbyopia which many associate with growing old), the harsh divisions in the zones can cause a distortion in the object you are viewing (an image jump) when you switch your gaze from one power to the next.
Progressive Addition Lenses (PALs)
Progressive lenses were designed to eliminate the “image jump” that results from the distinct zones in bifocal and trifocal lens design. By providing a smooth progression of many lens powers across the lens, PALs allow for clear vision near, far and every distance in between. Further, similar to natural vision, they just require a slight movement of the eye, rather than the whole head, for you to see through different lens powers. The smooth transition also eliminates the visible lines present on the other lenses which many view as tell-tale signs of age-related vision difficulties.
OCCUPATIONAL BIFOCALS & TRIFOCALS
Occupational bifocals and trifocals are specialized multifocal lenses created for specific jobs, hobbies or tasks. They are designed for people – generally over 40 – who have developed presbyopia, a condition in which the lens of the eye weakens and it becomes difficult to see objects that are close up. They differ from regular multifocal lenses in that the magnified power areas to see close and intermediate objects are typically larger and positioned in a different area on the lens, according to needs of the designated task.
Occupational bifocal and trifocal lenses are intended for specific tasks and not for everyday use. Here are a few examples:
The most popular type of occupational lens is the Double-D lens. The lens is divided into three segments, with the top designed for intermediate vision, the bottom segment for near vision and the rest for distance. This design is ideal for people who need to see close both when looking down (to read something) and when looking overhead. Professionals that frequently use Double-D lenses are auto mechanics (who have to look overhead when under a car), librarians, clerks or office workers, (who have to look at shelves overhead) or electricians (that are often involved in close work on a ceiling). They are called Double-D lenses because the intermediate and near segments of the lens are shaped like the letter “D”.
E-D Trifocal Lenses
As opposed to Double-D lenses which have the majority of the lens for distance vision, E-D lenses focus on intermediate vision with an area for distance on the top and for near vision on the bottom. These are ideal for individuals who are working at about an arm’s-length away the majority of the time, such as on a multiple computer or television screens, but frequently need to look up into the distance or close to read something. The “E” in the name stands for “Executive Style” which represents the division between the top distance vision lens and the bottom intermediate vision lens which goes all the way across the lens. “D” in the name of the lens is due to the fact that the near section in the bottom of the lens is shaped like a “D”.
Office or Computer Glasses
Multifocal lenses designed for office work provides the largest section with an intermediate lens designated for viewing the computer screen and a smaller area for limited distance vision. You can have progressive or trifocal lenses that incorporate near vision as well.
That’s right, there are even specialized lenses made for golfers! Golfers need to see a wide range of distances during their game from their scorecard, to their ball on the tee, to hole far away to line up their drive. In these lenses, the close segment is small and placed on an outer corner of one lens, to allow for brief close vision but not interfere with the distance game. Usually, right handed golfers will have the lens on the right side and vice versa.
Standard multifocals can be redesigned to adapt to specific tasks or hobbies simply by changing the size, shape or location of the different segments. Many adults over 40 would benefit from having multiple pairs of multifocals to give optimal vision for different tasks or hobbies they enjoy. Note that occupational lenses are made specifically for the task they are designed for and should not be worn full-time, especially while driving.
Progressive lenses or progressive addition lenses (PALs) are the most popular multifocal lenses today, offering an effective and great looking vision solution for individuals with presbyopia (age-related near vision loss). The main advantage of progressive lenses over standard bifocals or trifocals is that they don’t have a visible line bisecting the lens, but rather a seamless and gradual change in power as you move down the lens. Rather than two or three distinct zones (for near, far and intermediate), progressive lenses offer a smooth transition of focal powers that covers the total range of clear vision from close to far and every point in between.
As we age, particularly after the age of 40, our near vision begins to deteriorate. Progressive lenses allow you to see at all distances with one pair of glasses. They start with your distance prescription (if you have one) at the top of the lens and increase as you move toward the bottom of the lens. You simply move your head position to allow you to focus through different areas of the lens. Move your head upwards to see something in the distance, hold it straight for intermediate or arm’s length vision and down for near vision for objects that are close up.
In addition to the aesthetic improvement of the lens without the line segments (which tend to make people look and feel older as well), PALs avoid the visual discontinuity or image-jump when your eyes shift from one zone to the other in non-progressive multifocals.
Adapting to Progressive Lenses
While most people adapt to progressive lenses fairly quickly (many immediately), for some, getting comfortable vision with progressive lenses can take a few days. This is normal as you need to train your eyes to look through the appropriate area of the lens and get used to the slight adjustments when you move from one area to another – especially if you move your head quickly. If you find that you are not adapting to the lenses after a few days, speak to your eye doctor- they may not be the right fit or the right option for you.
Types of Progressive Lenses
There are a number of options for progressive lenses which vary in style, price and function.
Standard progressive lenses must fit to your vision needs. They can be added to frames of your choice, but you need to ensure that the frames are the right width and height proportions to grant enough space for the gradient changes in the lens. Otherwise only a small area will remain for the distance or near vision zones.
Short Corridor PALS
To overcome the issue mentioned above, there are now progressive lenses called “short corridor” lenses made to fit into smaller frames to suit a wider range of eyewear styles.
Also known as “near variable focus lenses” or “office lenses”, these specialized PALs are designed specifically for computer users and other occupations that require strong intermediate and distance vision. For computer users that work at a computer for many hours, these lenses will help to reduce eye strain, eye fatigue and other symptoms of computer vision syndrome that come from looking at a computer for extended periods.
PALs for reading
Individuals who enjoy reading can opt for a pair of lenses with a larger close vision zone. Free-form lenses offer a customizable surface with a wider area for near vision.
Progressive lenses are a great option for most individuals who require multifocal or reading glasses and still want to maintain a youthful look and appearance. Speak to your eye doctor about your specific needs and lifestyle to find the best option for you.
READING GLASSES AFTER 40
Once we reach the age of 40, its common to start noticing the natural effects of our aging eyes, such as having to hold your phone at arm’s length to read text messages. Medically, this normal change in our vision is called presbyopia and refers to the weakening of the lens inside the eye which is responsible for sharp focus and clear near vision.
You may begin to notice presbyopia setting in when reading starts to become difficult and the words begin to lose focus. You might also experience eye strain or headaches when trying to read fine print. This is where reading glasses come in. Reading glasses are non-prescription eyeglasses that magnify text (or any object you are viewing) to allow your eye to focus better at a close distance.
Styles of Reading Glasses
Single vision (as opposed to bifocal or trifocal) reading glasses come in two lens styles – full and half. Full readers offer a uniform magnification (the entire lens is the same focus) and you need to remove them to see clearly at a distance. These are ideal for individuals that spend a lot of time reading and don’t often have to look up during that time. Half readers are also uniform magnification but offer smaller frames that allow you to look over the lens when you want to see further away rather than removing the frame from your face.
Bifocal reading glasses offer two zones of vision within one less. The upper part of the lens allows for distance vision, while the lower part is for reading. Bifocals have a visible line across the midline which divides the two zones. You simply look into the part of the lens that offers the vision you desire.
Custom Made Vs. Over the Counter Reading Glasses
Over the counter or ready made reading glasses may be cheaper and more convenient than custom made glasses but they don’t take into account your individual needs. If you have no previous prescription and a light presbyopia, they may sufficiently suit your needs however in many cases, they can cause eye strain, dizziness and headaches when they are not the right fit for your vision.
Having an eye exam and ordering custom made lenses can meet your exact visual needs in each eye to create a comfortable and optimal correction for your eyes. You can also select the style and shape of the glasses that look and feel the best for you.
Even though presbyopia is a common condition that eventually affects most people at some point after 40, any time you experience vision changes you should see an eye doctor for an exam. Even if you decide that you want to start with ready made reading glasses, you should get an eye exam to ensure that your eyes and vision are healthy. Many serious and vision-threatening eye diseases can be stopped and prevented with early detection, so routine check-ups, especially when there is a change in vision, are critical for optimal eye and vision health.
DRY EYE AFTER MENOPAUSE
Dry Eye Disease is a common eye condition – studies show that nearly 20% of North Americans middle aged and older suffer from dry eye disease. The probability of you developing dry eye if you are a woman, and older than 50, increases. Hormonal changes that older women undergo make it much more likely that they will suffer from dry eye as they age, including symptoms such as blurry vision and irritation of the eyes, according to the American Academy of Ophthalmology.
What are the biological changes that happen during menopause which affect your eyes? The tear film in the eyes relies on certain chemical signals to remain stable, and these signals get disrupted during and after menopause. Some doctors believe that androgen, a hormone implicated in menopause, may be the culprit causing dry eye problems for menopausal women. Eyes may become inflamed, which leads to decreased tear production, and possibly dry eye disease. Add in a dry environment and many medications and the risk factors for menopausal women increases exponentially.
Treatments for Dry Eye in Menopausal Women
Estrogen hormone replacement therapy (HRT) is sometimes used to treat menopausal symptoms, as the female hormone estrogen is one of the hormones that decreases during and after menopause. However, studies have shown that this treatment does not relieve symptoms of dry eye.
Refractive Eye Surgery
Refractive eye surgery, such as LASIK and PRK, may not be advised if you are 40 or older, and have dry eye disease. These procedures can affect nerve function in your cornea (the clear surface of your eye), which could worsen your dry eye problem. If you want to have a consultation regarding LASIK or PRK, it’s important that your eye doctor know about your dry eye condition. In that case, your eye doctor will know to do the appropriate tests to make sure that there is enough moisture in your eyes for laser vision correction.
There are other health conditions that are associated with dry eye and aging. These conditions include thyroid autoimmune disease, and rheumatoid arthritis. If you suffer from dry eye, make sure your doctor screens you for these diseases.
Allergies may cause eye inflammation, and may be the cause of your dry eye. Prescription and over-the-counter eye drops might relieve your dry eye and allergy problem. Your eye doctor will advise you as to which eye drops would be best for you.
Sometimes commonly prescribed medications can worsen, or even cause, dry eyes. Some of these medications are antidepressants and diuretics, which are often prescribed if you have a heart condition. Make sure to talk about this with your doctor if you suspect that one of the medications you are taking may be causing your dry eye problems. Perhaps changing your medication will be as effective, and won’t cause dry eye disease.