Presbyopia Definition-A Complete Guide
Presbyopia definition, is it this what you are looking for,then article is a treat for you. this article explains presbyopia definition and much more like,
- What is presbyopia,
- Meaning of presbyopia,
- Causes of presbyopia,
- Mechanisms of presbyopia,
- Treatment of presbyopia,
- Management of presbyopia,
- Various options available for management of presbyopia,
- Contact lenses for presbyopia ,
- Spectacles for presbyopia ,
- Laser surgery for presbyopia -“Lasik for presbyopia”, and
- Refractive surgery for presbyopia-Lens Exchange.
Presbyopia definition ?
“I am in my 40s, and it has become increasingly difficult for me to focus clearly, when I am reading a book, or for that matter any kind of task I am doing at near”. This question summaries, in short the meaning of presbyopia.
Before proceeding further ,we would like to inform our readers, if you are having any problem or eyestrain in near work and also you are a “computer professionals” or “computer user” …then please read our article on computer vision syndrome ,which explains in detail about all the eye problems caused by working on computer ,and detail instructions on how to work on computer without eyestrain,and how to prevent computer vision syndrome. Please read computer vision syndrome and after that proceed further.
We have been gifted with our eyes, which have the extraordinary ability to focus at varying distances, and in addition this readjustment of focusing occurs at a subconscious level in less than fraction of a second. This is phenomenal, and is a state of the art nature’s mechanix ,a mechanism, which allows us to see everywhere and everything even though when they are at multiple distances,with precise focusing that too in less than a milliseconds.
This ability of our eyes which we enjoy all the time, right from our birth but, unfortunately there are some limitations to it.age related weakening occur’s and mechanics is unable to work efficiently.
The mechanism begins to fail , or becomes weak at around 40 years of our lives . And this failure of such a wonderful mechanism is called as presbyopia.
Mind it, this definition is meant for eyes with no pre-existing refractive errors.
But such is not the case when a person has pre-existing refractive error or glasses.such eyes behave in a different manner at around 40 years and beyond.
When an eye with refractive error gets presbyopia it behaves in slight different ways depending on the type of refractive error.
Myopia with presbyopia……..these individuals are extremely happy at the age of presbyopia ….as during this age,they are able to see near things or objects more clearly ….and that too……without any glass.
They mostly say, that they can see better or almost equal when it concerns to near objects with or without glass …only difference is mild manipulation is required in the working distance….and they are able to manage near work without glass in the early years of presbyopia.
Whereas in Hypremetropia (plus power glass prescription with presbyopia), individuals with refractive error are not very happy at 40 yrs of age .this is due to the pre-existing plus power ,now requires , extra help of larger glasses to see clearly at near,and these individuals become totally dependent on glasses for near work as well as distance.
Astigmatism (cylindrical power glass)– such individuals with the pre-existing cylindrical refractive error behave little different depending on the type of astigmatism they are suffering from. Going into details of astigmatism and the effect of astigmatism on presbyopia is out of the scope of this article, for further details click here “eyestrain cure”.
Now as we have understood what is the meaning of presbyopia, definition of presbyopia, effect of presbyopia on the pre-existing refractive error now let us try to understand the mechanism of presbyopia.
Primarily this total phenomenon is controlled by two very important apparatus. In general the perception of image and the focusing of image broadly can be classified as two different entities.
The optical system of the eye is responsible for the formation of the image in our eyes. This signal of image is than transmitted by the nervous system via a nerve called as optic nerve. This optic nerve acts as a connection between eyes at one end and the brain at the other end.
Optic nerve acts as a transmitter, which helps in transmitting the visual electrical signals formed in our eyes and these visual electrical signals are then passed on by the optic nerve and presented to the visual areas in our brain.
After receiving the signal, our brain then works on this electrical signals and then re-processors these signals, analyses these signals and then the signals are perceived as images by us. So this network is called as the perception of image.
Presbyopia solely affects the optical system of our eyes and has got nothing to do with the perception of image which occurs at the level of brain. Only if a blurred image of near objects is formed because of the presbyopia , such is the image which is presented to the brain and is definitely perceived as a blurred image.
One important thing here is to understand that the visual perception is not at fault but it is the optical system which is faulty in its behaviour due to presbyopia.
Simple correction of the presbyopia which is nothing but resetting or re-balancing the harmonious internal connections inside the eye ,by means of simple, beautiful aid called a spectacle for near work will bring back the balance between, all the components of our eyes and once again our eye is able to form a clear near image.
In medical terminology if one wants to understand about presbyopia it is actually the loss of elasticity of the lens capsule ,which is covering our natural lens and is also called as the lens membrane ,which is at fault and loses its elasticity ,consequently it is not able to respond and change its shape or the curvature ,which is the prime factor responsible for focusing and refocusing at varied distances.
This change of curvature of the lens is totally dependent on the elasticity of the lens capsule and which in turn is totally dependent on the contraction and relaxation caused by the ciliary body.
All the three parameters began to lose their efficiency and are not able to produce optimal results which is nothing but the disturbance in the harmonious relations between the three.
This disturbances caused by,
- The change in the lens protein structure due to ageing
- Loss and elasticity of the lens capsule due to ageing
- Reduced Efficiency of ciliary body and other diseases which are affecting ciliary body.
Major problem occurs because of the ageing which brings about change in the protein structure of the lens and this is an purely a natural physiologic phenomena and that is why presbyopia is not a disease, presbyopia is a condition which happens to everybody.
A very good example is of graying of hairs-which is the natural phenomena and happens to everybody, in a similar manner presbyopia is the natural decrease in the efficiency of optical system to focus near objects, and is also occurs to everybody.
Signs and symptoms of presbyopia:
- Inability to see near objects clearly at a normal working distance,patient is comfortable reading the text from distance then the usual near working distance.
- Blurring of image while working or doing a new revision task.
- Such near vision task, which can be done a little more comfortably only by increasing the distance away from the eyes e. if the image of the printed text blurred, one can increase the distance between the eyes and text by taking text further away from our eyes ,which enables them to see a clear image ,but such clear image is not possible from near.
- which will accompany a little minimisation in the image size and squinting of eyes.
- Headache and eye strain occurs while doing near work
- Heaviness of eyes and tiredness of eyes which is relieved by cessation of near work.
- All the symptoms get completely disappear ,by wearing a simple glass prescription for near work.
Presbyopia treatment and presbyopia exercises:
As stated above a simple glass prescription , which has additional plus power will relieve all the symptoms of presbyopia and forms the mainstay in the treatment of presbyopia.
This additional plus power lens in the spectacle makes the optical system of our eye even stronger and helps in the proper focusing of image on retina while working at near distances.
An optical system without the spectacle power is little weak and is not able to focus the image of an near object on Retina, on the contrary this week optical system focuses this image behind it, and that is why this image appears blurred.
Adding a additional plus lens makes optical system of our eyes stronger and the image of the object formed ,behind the Retina is then brought ahead by the powerful optical system and focused on the Retina and that is why the image appears clear.
Treatment of presbyopia–
In this modern world we have got quite a few strategies and options for the treatment of presbyopia.
But medically speaking, I believe treatment of presbyopia is not the proper terminology, because here we are not treating the presbyopia, but we are only making the patient to live comfortably with presbyopia and hence it should actually be called as management of presbyopia.
Patient’s life is made much more comfortable and he or she is not bothered about any near vision problems woth the correction in place.
And in this management of presbyopia we have got few wonderful aids like,
- Contact Lenses
- Presbyopia surgery-Lasers
- Presbyopia corneal surgery- Corneal Inlays
- Presbyopia lens surgery- Refractive Lens Exchange
Spectacles for presbyopia:
Even though we have many different options in the management of presbyopia the hallmark is formed by the spectacles.
Spectacles are the best, cheap, noncontact, easily modifiable, and possess very minimal risk. A presbyopia patient has got multiple options available in cases or spectacles. Such a patient can use a single near vision glass-also called as “reading glasses” and use them only for doing the near task like reading and take them away when he is not reading or when he is not involved in near vision task.
Bifocal lenses for presbyopia :
When an individual has got distance power because of any other reason, may be it could be a pre-existing myopia, hyperopia or astigmatism for distance when such a patient gets presbyopia, he faces an additional difficulty of near work, in addition to the pre-existing difficulty at distance work.
So as to manage both near vision as well as distance vision,a patient can use bifocal lenses in their spectacles, so that he can see distance as well as near objects clearly and comfortably.
The only problem in bifocal lenses is that, it possesses a distinct line of demarcation between the distance and the near lens. Cosmetically this might affect certain individuals, especially ladies, which make them look aged.
Progressive lenses for presbyopia :
Progressive lenses are the ones which , do not possess any kind of line of demarcation, and they appear as a single normal piece of glass. Due to the absence of any line of demarcation cosmetically it is much more acceptable by all the age groups. Additionally progressive lenses possess different powers which are embedded in the same lens and all these powers are used by our eyes to work at different working distances. And that is why, these lenses are very comfortable to work at different working distance.
Pros and cons of progressive lenses for presbyopia :
- All individuals take little time which can range from one week to 3 weeks for getting adjusted with the progressive lenses. It requires little training of our eyes so that they can work in harmonious way with the orientation of the glasses and different powers which are embedded in the progressive lenses.
- Expensive as compared to bifocal lens.near vision or reading glasses are the cheapest, also available as ready made spectales,over the counter in optical shop.
Contact lenses for presbyopia :
Multifocal contact lenses are available, but they are not very practical solution for the patients of presbyopia. Nothing further will be discussed about multifocal contact lens for the management of presbyopia.we discourage the use of such products.
Mono- vision, contact lenses for presbyopia :
Here we use two different contact lenses, so as to achieve different optical states for the eyes.
Here we make the dominant eye to focus for distance objects and the non-dominant eye is made to focus for near objects with the help of contact lens and such a contact lenses prescribed for the patient of presbyopia.
Some patients are not very comfortable because they lose the depth perception by using such contact lenses. Again nothing further will be discussed about “monovision contact lenses in the management of presbyopia”; this topic is out of scope of this article.
Corneal inlays ( corneal implants) for presbyopia :
This is a surgical procedure, in which an inlay (implant) is used or implanted inside the cornea ,so as to achieve the desired optical benefit.
In this the surface of the corneal curvature is altered with the help of laser, again not a very popular treatment and further discussion is out of scope of this article.
Lens exchange refractive surgery :
In this surgical modality of treatment, the natural lens inside our eye is removed and it is replaced by an artificial intraocular lens .
These intraocular lenses could be either mono-focal or multifocal.
“Multifocal intraocular lens” this topic has been discussed elsewhere on our website.
Presbyopia is a condition in which one is not able to perform near work comfortably at proper working distance at around 40 years of age. It is not, a disease but it is a part of natural aging phenomenon which leads to weakening of the eyes .
Various modalities of treatment and management of presbyopia are available, depending on the state of the eye, profession of the patient, and expectations of therapy by the patient and lastly proper consultation and examination by an eye doctor will determine, which of the modalities of treatment will be more comfortable for the patient and is more helpful to the patient without causing unnecessary side effects, problems and botheration in their daily life. Such a modality is selected by the patient to tide over near vision problems which the patient is facing in his daily life.
Please consult your Eye Specialist Doctor and then take a proper decision regarding the modality of treatment, which you would like to use.
Hopefully this article has explained in detail and in simple language, what is presbyopia meaning of presbyopia, causes of presbyopia, mechanisms of presbyopia, treatment of presbyopia, management of presbyopia, various options available for management of presbyopia, contact lenses, spectacles, Lasik, and lens exchange.
This article is written with the aim of educating and creating awareness regarding presbyopia and proper selection of options for the management of presbyopia. This is a part of our patient education program, for further information on different diseases please kindly visit our website-EYE CARE CLINIC ,CHILDREN’S EYE SPECIALIST IN MUMBAI.