This is presbyopia, a visual disorder ‘typical’ of advancing age that causes images that appear ‘close’ (ie at a distance of 30 to 40 centimetres) to appear blurred.
But what happens to our eyes after the age of 40? What are the alarm bells that tell us if we have presbyopia?
And what options are there today to fix this vision problem?
Presbyopia: a problem of vision and old age
The term “presbyopia” comes from the Greek words “presbus” (old, respectful) and “opia” (seeing) and describes a visual disorder that is completely age-related and therefore physiological.
Unlike the more common refractive errors (myopia, hypermetropia, and astigmatism) that result from an abnormality in the structure of the eye, presbyopia is caused by the loss of flexibility of the crystalline lens, the lens inside the eye.
Over the years, the central part of this lens (nucleus) loses water, hardens and can no longer change shape to focus on near or far objects.
The lens of the eye then loses its ability to “accommodate,” that is, to maintain a clear view of objects at different distances.
Presbyopia makes it difficult to see up close.
It should be noted that presbyopes use two different corrections for distance and near vision.
In fact, even the slightly nearsighted person who reads without glasses is presbyopic, meaning they wear glasses for distance and take them off when looking at objects or writing about a foot away.
The alarm bells of presbyopia
The 45+ year old notes some difficulty in distinguishing the images on the phone screen, feels the need to move away from books or newspapers to be able to read the text and perceives some eye fatigue, especially during any activity performed at close range.
These symptoms worsen with age.
In rare cases, presbyopia can appear as early as the age of 40.
In such cases, diseases such as diabetes, multiple sclerosis, cardiovascular diseases or taking medications such as diuretics, antihistamines and antidepressants contribute to the accelerated appearance of the problem.
Eye exam to diagnose presbyopia
Presbyopia is a clock provided by Mother Nature to encourage everyone to see an optometrist, and for many this will be the first eye exam of their lives.
The specialist not only assesses the degree of correction of the glasses, which often have a very simple correction power, but also the health of the eye.
In this examination, the visual acuity with the most reliable possible diopter correction, the intraocular pressure and the fundus of the eye are checked in a targeted manner, which is particularly recommended if there is a family history of diseases such as glaucoma and maculopathy.
To check visual acuity, i.e. the ability of the eye to focus on objects correctly, the “classic” visual measurement is usually carried out using the octotype table.
This is a board that usually consists of letters of different sizes, which are arranged in several rows on top of each other.
The person looks at the board from a certain distance, first with one eye, then with the other eye, and the specialist checks that the letters are read correctly.
Correcting presbyopia: glasses and contact lenses
Presbyopia is generally corrected by prescribing glasses.
The choice of the most suitable lenses for the correction is suggested by the specialist depending on the person’s age, the severity of the problem and the possible presence of other related refractive errors (myopia, astigmatism and hypermetropia).
In some cases, multifocal soft contact lenses can also be used, which are particularly recommended for people who have been wearing contact lenses for a long time to correct other ametropia.
In addition to the traditional means of correction, glasses and contact lenses, refractive laser surgery has been used to correct presbyopia since 2005.
Surgical options to correct presbyopia
Laser surgery can be an effective solution for presbyopia because it increases the depth of field, thus providing good comfort for medium-distance vision (the distance at which we usually have a computer screen) and helps with near-vision vision (books, newspapers). and smartphones) in a well-lit environment.
It is particularly indicated when presbyopia is associated with other refractive errors such as myopia, astigmatism and hypermetropia.
In the field of refractive laser surgery, 2 techniques are most commonly used: excimer laser (with PRK technique) and femtolaser (with Lasik technique).
Excimer laser (PRK technique)
The excimer laser (PRK, PhotoRefractive Keratectomy) is the treatment with the most experience worldwide (since 1990).
It consists of remodeling the front surface of the cornea, the first lens of the eye, after the surface epithelium has been mechanically removed (de-epithelialization procedure).
To correct the refractive error, a “natural contact lens” is molded with the desired dioptric power, and in the case of presbyopia, an area of multifocality is modeled on the front surface of the cornea to help the patient see near.
Only through the precision of the laser beam can corneal tissue spots of one micrometer (one thousandth of a millimeter) be removed at each “spot” (blow).
It is therefore a treatment that has the advantage of being carried out on the surface of the cornea, without the surgeon having to manipulate the eye and therefore without intraoperative risks.
It causes some pain in the 2-3 days after the treatment.
Femtolaser (with Lasik technique)
In the Lasik technique, the femtolaser first cuts the cornea sagittal.
The flap is then raised by the surgeon who, with the second instrument, the excimer laser, modifies the curvature of the cornea by excavating it inwards according to the required treatment parameters (as in PRK).
Like PRK, this technique not only enables the correction of presbyopia, but also of any other ametropia that may be present.
Femtolasik is particularly recommended for the correction of severe ametropia, especially in the case of farsightedness and astigmatism.
The FemtoLASIK technique is more invasive than PRK, but painless after the operation.
If the lens of the eye becomes opaque and cataracts occur, cataract surgery with implantation of an intraocular lens or an artificial lens can be used to correct presbyopia as an alternative to refractive laser surgery.
These lenses are accommodative or multifocal, meaning they are able to focus the eye on near and far simultaneously. They won’t become opaque and will last a lifetime.
This procedure enables the simultaneous correction of associated refractive errors such as myopia, astigmatism and hypermetropia.
It should be noted that the most appropriate operation must be judged by the surgeon based on age, severity of symptoms and the presence of other refractive defects.
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