Varionet News
How not to rub your eyes?
Do you tend to rub your eyes? And you wonder why and is it dangerous in this time of COVID-19?
Why are you rubbing your eyes?
This could be due to several things. You may have dry eyes, an eye infection, wear contact lenses, be prone to allergies or another health problem. Rubbing your eyes has become a habit for you
How to recognize presbyopia?
Presbyopia, what is it?
Presbyopia is a natural age-related phenomenon ; it is a change in near vision which gradually becomes blurred and wearing glasses to read is then essential. It appears around 40 years, increases until 60-65 years to stabilize. The term “presbyopic” appears around 1690 and comes from the ancient Greek “presbutês” meaning “old”!
What are the symptoms of presbyopia?
These signs are numerous and happen without even realizing it. One of the first symptoms will be asthenopia or more commonly all the manifestations linked to the fatigue of the ciliary and oculomotor muscles ; you feel a feeling of fatigue such as eye discomfort, tingling, headache, fixing his attention becomes more and more difficult.
These genes are all the more important when the light is low, we approach the windows, we seek the best angle to be able to read. The most characteristic sign of presbyopia is pulling a document away to read it, the symptom of “arms that are too short”.
Putting on make-up, sewing, tinkering, reading, all activities requiring near vision are becoming more and more laborious, even impossible.
How presbyopia works
Presbyopia is due to the natural decrease with age of the ability to accommodate the lens when reading .
To see up close, crystalline , transparent lens inside the eye, bulges quickly under the action of the ciliary muscle, it thus increases its power of refraction, to form a sharp image whatever the distance on the retina: it is the 'accommodation.
This accommodation is therefore a very rapid movement of the lens and can be compared to the focusing of autofocus devices.
The value of accommodation varies with age: very important in children (12-14 diopters at 10 years old) it is at its maximum around 20 years old (10 diopters) then begins to drop: 6 diopters around 37 years old, 4 diopters at 45 years old to reach 1 diopter around 60-70 years old.
Inevitably, the lens ages with age and loses its elasticity, it hardens. The action of the ciliary muscle on this more rigid lens becomes difficult, the accommodative power of the eye decreases.
Focusing for near vision is no longer done correctly.
In the presbyopic, the accommodative power of the lens decreasing , the image of a close object is no longer on the retina but behind it . The net reading distance increases; we move the text away but the size of the characters limits this distance! Vision at the usual reading distance becomes blurred.
How is presbyopia corrected?
To compensate for this lack of accommodation, near vision must be optically corrected with reading glasses equipped with convex lenses, of positive power, it produces a magnifying effect ; then the image will form again on the retina. Presbyopia is measured in diopters from 0.25 to 0.25 from +0.75 to +3.50.
This correction is determined according to your working distance and your age.
To this defect of near vision, can be added visual defects of distance vision such as myopia, astigmatism or hypermetropia. Then on your prescription appear 2 corrections: that of vision from afar and that of near often noted in the form of an addition.
The correction of presbyopia evolves approximately every 2-3 years; you will then have to take the opportunity to consult an ophthalmologist who will not only check your visual needs and can also detect any other visual condition, glaucoma, AMD, conjunctivitis…
New technology lenses
Improving the quality of life of people with AMD
AMD , age-related degeneration , is a visual disease which affects more than one million French people, it is one of the leading causes of visual impairment in people over 60. This is irreversible, it is due to age but also to tobacco and blue light released by the screens of computers, tablets, smartphones, etc.
New solutions are available to us. Indeed, researchers from the University of San Diego and the Ecole polytechnique de Lausanne have developed a lens which, combined with a pair of 3D glasses , allows the patient to have a telescopic view. Through it he could see details up to 3 times bigger .
Zoom lenses
These lenses actually have two fields of vision . One magnified and the other is normal, when the wearer blinks his right eye, the lenses will begin to zoom, when he blinks his left eye, vision returns to normal. It is the coupling of two lenses that allows it to work in this way.
This innovative technology would allow many people to regain a quality life thanks to a single device. Today these lenses are rigid and not very comfortable, but researchers are working on a flexible lens, which allows air to pass through and is therefore more comfortable to wear.
An operation to fight AMD
Another solution exists for people with AMD: a surgical operation to graft a mini telescope into their eyes. Inserted in place of the lens, it helps to gain vision thanks to its magnifying properties. Additional hope for subjects with low vision and their loved ones.
