Presbyopia simply means old age sight or old sight. It is loss of accommodation that comes with aging to all people. A person without refractive error (especially long sightedness) will begin to notice inability to read small print or discriminate fine objects at about 40 – 45 years. This is compounded under dim light or by fatigue. This problem increases as one continues to grow older especially between the age of 40 and 55 years.
During a period of about 10 years, the reading glasses (power) must gradually be increased in power. This is why people within this age require eye checkup every year or at most every two years.
The near point of focusing (accommodation) gradually recedes from childhood onward but most people are not aware of it until in the early 40s. At this early 40s, they attempt to read the fine print on a medicine bottle or insurance policy and find to their surprise that it blurs at a distance of 7 or 8 inches.
Presbyopia typically begins between the ages of 40 and 45, and the power of the required reading glasses or bifocal increases gradually and levels off at about the age of 55 yrs. During the intervening 10 – 15 yrs period, the patient may require fairly frequent lens changes. It is not unusual to see a patient below 40 yrs complaining of reading difficulty (Presbyopia). It is worthy of note that some people become presbyopic at earlier age (38 and 39 yrs.)
It is expected for a Presbyopia to increase every two to three years. After a patient has worn reading glasses for a year or two, the patient may return with the complaint that the lenses that were originally suitable for near work are no longer effective. This requires an update of such glasses.
Please note that the occurrence of Presbyopia is a universal phenomenon just as certain to occur as “death and taxes”
Scientific explanation on Presbyopia
Since this magazine is targeted at the general public (non-professional), we shall be as simple as possible on the scientific explanation. Please see appendix for unavoidable technical words.
Presbyopia is though often regarded as an error in the eyes (error of refraction) but it is actually a problem of accommodation (focusing) brought about by changes in the structure of the crystalline lens with age.
The crystalline lens continues to grow throughout life. This means as one grows older the lens grows older too. As the lens grows older, it continues to lose its flexibility and elasticity. The crystalline lens requires much elasticity and flexibility to focus for us especially when reading. When the lens grows older it loses this flexibility (power to focus). As it is losing its elasticity, the power to focus continue to reduce.
Symptom and Signs of Presbyopia
- You will need to stretch your hand or push prints far away from you before you can read.
- You will experience intermittent blur vision if you attempt to read for long. (fatigue)
- The eyes bring out tears sometimes, after reading for a while.
- You can experience heaviness in your eyes.
- You will have difficulty reading under normal light.
- You will experience difficulty reading under normal lighting conditions.
You may now require very bright light to read.
- Reading is unusually worse in the morning or when you are stressed.
- You will have feeling of sleepiness when reading.
Correction of Presbyopia
Presbyopia is corrected by use of a plus lens to make up for lost automatic focusing power of the lens. The need for reading glasses or bifocal lenses varies greatly from one person to another. When prescribing for Presbyopic patient, the following factors are considered:
- Occupational need
- Arms length.
Occupation is vital when prescribing glasses. An NEPA official who reads meters may require a different glasses compare to a tailor. A book worm requires different attention from a TV watcher (hobbies). A three feet tall man is expected to read at a shorter arms length than a six feet tall man.
So when next your eye doctor wants to place you on reading glasses, please remind him of the two most important factors: your occupation and hobbies.
Correction of Presbyopia requires reading glasses only. It does not require drug or surgery. There are three categories of glasses that can be used to correct Presbyopia. These are
* A reader
A reader is such glasses that have the power (a single power) in the entire aperture of the glasses, making them fine for reading but blur for distant objects. It is meant for reading only. It cannot be used for computer work except the user goes closer to the monitor. Going too close to the computer monitor is stressful to the eyes.
Bifocal glasses are those with two distinct portions, one in the top half of the lens for distance and the other in the bottom half for reading, with a distinct line dividing them. It is not convenient for computer work.
Progressive or Varifocal
Progressive glasses are those glasses that have gradual power shift from the distance correction at the top of the lens to the close-up correction at the bottom, without a visible line dividing the two. It is also known as Varifocal glasses.
Progressive as the name implies, is made up of multiple powers for different focal points. They are improved versions of the bifocal and their major advantage over bifocal is that they have no line that demarcates the reading portion from the distance portion. They are blended to look simple like a plane glass. They are made up of an intermediate power. The reading area is smaller than that of a bifocal lenses.It is very useful for computer work and ideal for all occupations and hobbies.
Facts to know about Presbyopia
- Presbyopia is not a disease, but a fact of life for which the optical industry has provided many options. So make use of the opportunity.
- Presbyopia is not losing your sight but an aging process. So do not despair.
- No drugs solution for Presbyopia. It only requires reading glasses. So do not waste money
- Presbyopia becomes worse as aging continues. So be prepared.
- Food, fruits or vitamins (supplement) cannot stop or reverse Presbyopia. So do not waste your resources.
- Eye aerobics or exercises cannot reverse or stop Presbyopia. So do not waste your energy.
Now you will agree with me that Presbyopia is not a problem or a disease as many people believed. If you are experiencing the symptoms of Presbyopia, do not distress. All you need is to consult your eye doctor immediately for a solution. Also regular routine eye test is important once you are above forty years. There are other degenerative changes in the eye that are dangerous. Only routine eye test can uncover them.