Glaucoma & Cataract, Prof. Eytan Blumenthal | Presbiopia - decreased vision for near, and the need for reading glasses

Presbyopia

The Necessity for Reading Glasses over the Age of 45

Throughout the course of a person’s life, the eye undergoes various changes in structure and function. These are normal changes and do not indicate illness.

One of these changes is connected to the fact that the natural lens, which is responsible for the focusing mechanism of the eye, becomes less and less flexible over time. As a result, the ability to focus on objects at varying distances is lost with time, especially for objects that are close by.

Generally, around the age of 45 (give or take a few years), it becomes difficult to comfortably read at a distance of 30-40 centimeters. This difficulty is often most noticeable when a person holds the reading material farther and farther away from his/her eyes. This condition is known as presbyopia and is natural and normal in all normal, healthy eyes over the age of 45. Of note, this phenomenon affects men and woman equally.

The loss of elasticity of the natural lens (and therefore of the ability to focus objects that are close), is the reason why reading glasses become necessary. Reading glasses reduce the burden of focusing which the natural lens can no longer perform adequately, since it is no longer flexible enough.

It is common that almost every person over the age of 45, and especially so those who never wore glasses, will gradually require the addition of reading glasses. The thought, that a person who up to that point in time never needed glasses will suddenly require them for reading and will have to remove and put them on an endless amount of times a day, is not a happy one. When vision for near is reduced to the point that reading glasses are needed, every view of one’s cellular phone, watch, or electronic diary, as well as reading and even looking at a bus ticket, suddenly requires to put on a pair of reading glasses, not a comfortable thought indeed.

At the same time, it is, perhaps, encouraging to know that it is a natural and normal process that does not indicate an illness. Getting used to reading glasses may not be easy at the beginning, but putting on your first pair is often accompanied by a feeling of relief at finally being able to comfortably read the smallest text, text which has become gradually more and more blurred to the point that without reading glasses it is impossible to interpret from a comfortable distance.

There are different approaches to the use of reading glasses. There are those who wear them only when necessary, meaning, they put them into and take them out of their pockets every time they need to read something that is close. There are those who wear them in such a way that when looking at a far object the line of sight does not pass through the glasses, whereas when looking at an object that is close (generally gazing downward), the glasses which sit slightly under the line of sight, come into play. The third option is to create a pair of glasses which look like regular glasses (they do not sit low down on the nose), however the upper segment of the lenses do not have a number (a power of 0 implies that they are nothing more than “window glass), while the lower segment consists of reading glasses. This type of glasses may be bi-focal, or multi-focal. One variation of these glasses is called an “office pair” which has computer-friendly refraction in the top segment, and reading-friendly refraction in the bottom segment.

Of all the options mentioned above, what would be the right way to prepare for the sudden necessity for reading glasses?
Well, first of all, this transition is not sudden, but takes months to a few years during which the feeling that reading up close is harder and harder creeps up on you, accompanied by eyestrain from reading long periods of time.

The proper way is to go to an optometrist in an optics store and to request that he briefly explain the various options and ask his opinion about the best option for you. If you find it difficult to decide which option is appropriate for you, it is sometimes wise to think about it for a few days, and also to go into another store in order to compare the possibilities that they present you with. For those who are not able to decide, and who can allow themselves to do so from a financial standpoint, it is possible to order two kinds of glasses and to alternate wearing them. After a few weeks you will likely figure out for yourself what best suites your needs. Obviously, the second, less comfortable glasses can serve as a backup pair which is always good to have lying around.

Since prices of glasses vary tremendously between different stores, it is always advisable to shop around for style, comfort and price.

One important Advice

For those people who for reasons of work or leisure, spend a lot of time reading or using a computer and who require reading glasses, it is important to know that in addition to multi-focal (or bi-focal) glasses, it is advisable to have another simple pair of reading glasses that can be used when working up close for long periods of time. Such a pair of glasses has lenses that are entirely for reading. Since this pair of glasses is usually used in bed (for reading), or in the office, the frame need not be fashionable (in other words, expensive) but rather comfortable and practical.

The reason that I mentioned reading and working at a computer separately is because the strength of reading glasses required for reading is not identical to the power needed for working at the computer. This is because the computer screen is generally twice as far as the distance that one would normally hold a book. Therefore, I recommend to my patients, who spend a lot of time using a computer as well as a significant amount of time reading, to have two pairs of glasses – one for reading, the other for the computer. Another option to consider for those who do not require glasses for distance, is to use bi-focal glasses that include the range for computer work in their upper segment, whereas the lower segment is designed for reading.

It is important to note that those people who wore glasses their entire lives, whether for Myopia or for hyperopia, (see appropriate sections), the reading glasses will generally accompany or be incorporated into the glasses that they habitually wear. In their case, their optometrist, who most likely already follows them for many years, will hint to them that the time has come to consider combining a reading segment within their habitual refraction which they already wear.

It is interesting to know that, occasionally, people who wear glasses for distance, will not notice that while they continue to see objects that are at a distance clearly, objects that are close up begin to appear more and more blurry. This may manifest as holding the reading material further and further away from one’s eyes. If this is true in your case, it is advisable to go to an optometrist and request new glasses that will also answer the need for reading comfortably and having sharp vision for objects that are near.

Last, note that reading glasses (or the reading segment in your multifocal/bi-focal glasses) needs to be strengthened every 3-5 years. This is because our natural lens loses its elasticity with time, starting at age 45, but continues to lose elasticity even more as time goes by. Consequently, the reading add for age 45 would be too weak for those 50, and the reading add at 50 too weak for those at 55.

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