Presbyopia is a universal condition associated with the aging eye’s diminishing ability to focus on close objects. It is neither a disease nor a defect. People usually discover this trouble during their mid-forties, and can correct it with lenses adapted to their various needs. Although presbyopia is a natural condition that everyone has to face sooner or later, proper diagnosis, eye care, safety precautions and monitoring of the condition can give our eyes a new lease on life!
What is presbyopia ?
Presbyopia is a common vision condition in which it becomes increasingly difficult over time to focus on objects that are within close range. People with presbyopia find they have to hold reading material at arm’s length or move their computer screen back in order to bring text into sharper focus. Signs of this defect include eyestrain, headaches, eye fatigue, blurred vision and a diminishing ability to maintain focus on near objects.
We we will all experience presbyopia sooner or later during our lifetimes. It generally occurs earlier in farsighted people than in nearsighted people, but no one develops presbyopia overnight! Presbyopia progresses gradually over the years, typically becoming more noticeable in the early to mid-forties. People who live in tropical climates and at sea level tend to develop this condition sooner.
As we grow older, the flexible crystalline lens of the eye hardens and loses its elasticity. At the same time, the ciliary muscle which surrounds the lens weakens and loses its tone. When the lens of the eye loses its range of adjustment, the image that the eye takes in is focused behind, rather than on, the retina (the nerve-rich lining inside the eye, where we “see”), and vision becomes blurred.
Surgery will not halt presbyopia today. In fact, whether or not you have had eye surgery in the past, by your mid-forties you will likely find you need corrective eyewear.
When presbyopia is corrected with single-vision eyeglasses, one to three pairs may be required, depending on the wearer’s needs (for instance one for reading plus one for driving). Reading glasses, bifocals, trifocals or the newer, progressive addition (multifocal) lenses are also available. Those are also simply called : " progressives ".
Bifocal lenses may take a while to get used to, especially if you have never worn glasses before. Progressive, or “no-line,” lenses are becoming increasingly popular, as they disguise the fact that you are wearing reading glasses, while providing clear vision up close, far away and at every point in between. The latest models can be custom-made by a trained eye-care professional to suit the special requirements of your work, leisure, hobby or home environment, and are the next best thing to natural vision, so they are easy to adapt to.
Progressive contact lenses using varying concentric zones of magnification are some of the newest and most successful products for presbyopes who prefer not to wear glasses.
For those interested in a therapeutic approach, there is monovision. In monovision, a contact lens with closeup correction is worn in one eye, and (if necessary) a contact for distance correction in the other eye. Within approximately 10 days, your brain will adapt to the change, and you will be able to see reasonably well throughout your range of vision. However, this kind of vision therapy takes persistence, and many experts do not view it as a long-term solution.
There is no proven way of preventing presbyopia, since it is a natural condition that occurs during the aging process our eyes are destined to undergo. So, as with any vision condition, standard eye care practices apply (see Prevention). Some people use the cheap reading glasses that can be purchased at a drug store, but their vision may suffer if the wrong strength of magnification is selected. Regular eye examinations and prescription eyewear are the best solution, especially since the ability to focus tends to worsen over time and the strength of prescriptions should be changed to maintain clear, strain-free vision. Once diagnosed, presbyopia should be treated as soon as possible since it can complicate other vision defects like nearsightedness, farsightedness and astigmatism.
Given that the clarity of your eyesight is likely to change over the years, you should take a few precautions to enhance the safety and convenience of your surroundings. Start by making periodic spot checks to make sure that lighting is adequate both during daylight hours and at night. To avoid potentially dangerous situations, increase the amount of light you have in your living and working environments. Add quality lighting or change light fixtures to accommodate higher wattages around
- outdoor locations you frequent at night
- garages
- storage areas
- stairways
- work spaces
- favorite reading places, etc.
And since lighting in other environments is not always ideal for reading of small print, make sure a powerful portable flashlight is on hand in your car or in a carry-all bag to make sure you can find your way — wherever you go!
You may notice that your vision is better in the morning than it is at night. If so, plan your activities with maximum efficiency in mind. In many cases, the ability to see in the dark also diminishes in presbyopic people and increased sensitivity to glare may cause road blindess. Use caution when walking near traffic. And for the safety of all, drive on well-lit roads and keep your windshield, headlights and eyewear clean. It is also strongly advisable to wear anti-glare glasses to minimize risks on the road. In some cases it may also be advisable to avoid driving at night.
If you are under 40 and notice any of the signs of presbyopia mentioned above, consult your doctor before you see an eye specialist. Conditions like anemia, diabetes, cardiovascular problems, infections, cataracts and sclerosis of the lens can bring about similar symptoms, and should be checked for and treated before any prescription for eyewear or intervention is provided.
Although it might be said that American inventor and statesman Benjamin Franklin was a man of vision throughout his life, by mid-life he found that his vision needed a little readjusting! One day, while reading, he suddenly realized he could not decipher the print of his newspaper without using magnifying eye glasses. As a man of science, Franklin’s activities required that he wear glasses to see objects at a distance, but he also had to be able to concentrate easily on his reading and writing. He could have continued using the magnifying glasses to read. But this business of changing spectacles every few minutes was threatening to drive him to distraction!
After some thought, the American man of invention soon found the solution. He cut his lenses in half, fastening distance lenses to the top portion of his frames and his reading lenses to the bottom portion. Eureka! A new invention was born in America: bifocals.
Ben’s legacy
Some two centuries later, the eyeglass industry took Benjamin Franklin's brainchild one step further. In the late 1950s, the first patent was granted for progressive “no-line” lenses in France. Always interested in the latest innovations, you can bet that Ben would have been first in line to change his unsightly specs!
Sources
“Presbyopia and its correction,” In: Points de Vue, No. 32, April 1995, p. 12–18
For more information
http://www.merk.com/pubs/mm_geriatrics/102x.htm.
http://bewell.com/healthy/man/1997/vision/
http://med-aapos.bu.edu/PublicInfo/store2/
http://www.aoanet.org/
http://www.aoanet.org/
http://www.healthscout.com/cgi-bin/
http://www.healthscout.com/cgi-bin/
http://www.merck.com/pubs/mm_geriatrics/102x.htm
http://www.mayohealth.org/mayo/9510/htm/vision.htm
http://www.hslib.washington.edu/your_health/hbeat/
