Visual defects, let's talk about presbyopia

By Cristiano Antonino On Jun 9, 2023

Unlike astigmatism, nearsightedness, and farsightedness, presbyopia is not a refractive error. Instead, it is a physiological reduction of the accommodative amplitude and, therefore, of the maximum level of accommodation that an eye corrected for any refractive errors can produce with voluntary effort

Thanks to accommodation, in fact, the lens increases its convexity allowing the convergence of light rays coming from a nearby object and therefore, more generally, near vision.

Those suffering from presbyopia are unable to focus on objects closer to each other due to the loss of elasticity of the lens

This is an event that generally occurs with advancing age (the first symptoms appear between the ages of 40 and 45): it is precisely the passage of time that is the main cause of presbyopia, together with other pathologies such as diabetes , cardiovascular diseases and multiple sclerosis, or the prolonged intake of certain drugs (diuretics, antidepressants, antihistamines).

The disorder is widespread: 28 million people suffer from it in Italy (9 million are between 40 and 50 years old), 2 billion worldwide.

Although the period of onset is not the same for everyone, at age 65 presbyopia affects everyone.

Today everyone experiences this condition due to the increasing amount of time spent in front of smartphones, computers and technological objects in general.

Presbyopia: what is it?

Presbyopia is a typical age-related visual disorder.

As a person ages, the nucleus of the crystalline lens loses water (and therefore its elasticity): it becomes harder, the refractive index increases, and here it is difficult to focus on an object placed near the eyes.

The loss of elasticity is a physiological process: it already begins in children, but its effects start to be felt between the ages of 40 and 50.

That’s why if you experience difficulties in reading up close and focusing on objects close to the eyes at a young age, the causes are to be found in other disorders.

Hyperopia, for example, has similar symptoms

Nearby objects, in fact, appear blurred and confused, the eyes get tired, but the cause is not aging or even the presence of another pathology.

On the other hand, a cornea that is too flat, an alteration in the length of the eyeball or a lens that is too curved or not thick enough is responsible.

In those suffering from presbyopia, on the other hand, everything starts from the crystalline: stiffened, this cannot adapt to nearby objects (in medical jargon, to accommodate).

When the pathology is in its infancy, it is sufficient to move the objects away a little to be able to see them better, then it will be necessary to intervene with glasses, lenses or surgery to restore vision.

There are three types of presbyopes

young farsighted: between the ages of 40 and 45 the person has difficulty reading and observing nearby objects and, to help himself, he limits himself to moving the objects away from his face or makes use of a slight correction;
presbyopic: between the ages of 45 and 55 the person needs to use glasses with specific corrective lenses, to perform many activities;
advanced presbyopic: after the age of 55, the person has lost most of his ability to accommodate and is forced to use glasses even for activities that require good intermediate distance vision

Presbyopia: causes and prevention

The number one cause of presbyopia is aging. A young lens is elastic, capable of focusing on both distant and near objects (except for refractive pathologies).

Subsequently, that elasticity is lost due to the loss of water from its nucleus: the lens stiffens and presbyopia occurs.

However, age is not the only cause of the disease.

There are other risk factors, to be found mainly in the abuse of drugs and in certain pathologies

diabetes
multiple sclerosis
cardiovascular diseases
chronic autoimmune diseases
diuretics
antidepressants
antihistaminescortisone
alcohol abuse

When presbyopia occurs before the age of 40, it is called premature presbyopia

This phenomenon is increasingly frequent, due to the high amount of time spent in front of electronic devices: prolonged use of computers, smartphones and tablets forces us to continuous efforts to accommodate, and here is that presbyopia appears first.

As it appears first in hyperopic and astigmatic subjects.

On the contrary, in those who are nearsighted, presbyopia seems to improve the “primary” disorder and its effects are felt at an older age.

Although it is a physiological process, presbyopia can at least be delayed.

It is important to carry out periodic eye examinations (every 2-3 years starting from the age of 40, every 1-2 years after the age of 55 and annually after the age of 65, unless otherwise indicated by the specialist).

For those suffering from diabetes and hypertension, it is essential to keep their diseases under control since they could have consequences on their eyesight.

Among the other preventive behaviors to adopt are:

always wear sunglasses when outdoors
avoid smoking and alcohol
do regular physical activity
consume fruits and vegetables
maintain proper eye hydration by drinking enough
favor foods that are good for the eyes: vegetables and orange fruits, blueberries, oily fish, salmon, dried fruit
if you work on the computer, take a break every half hour (preferably looking out the window)
spend as much time outdoors as possible
use the right lighting when reading, to avoid straining the eyes too much
take, if the doctor deems it appropriate, supplements of beta-carotene and vitamin A

Presbyopia: the symptoms

The person who suffers from presbyopia (farsightedness) becomes aware of the pathology because, when he brings an object close to his eyes, it appears blurred.

Often, in reality, the first and most obvious symptom is reading difficulty: the letters seem double, the eyes get tired quickly, they can burn and redden.

My head often hurts, especially at night and in the evening.

However, it is the difficulty in reading and seeing up close, the sign that most of all indicates the onset of presbyopia: while you don’t have problems seeing road signs or watching TV, reading a book or the restaurant menu becomes difficult if it does not push them away from the face.

At the beginning it can be a minor ailment, which the person tends to overlook, but over time it tends to get worse rapidly.

Diagnosis and treatments

The diagnosis of presbyopia is made by an ophthalmologist.

The presbyopia test uses the optotype table, which measures visual acuity in tenths.

In case presbyopia is ascertained, it will be decided which tool to intervene with.

The most immediate solution is represented by glasses with positive lenses, bearing however in mind that presbyopic lenses are not definitive lenses: they can be used in the absence of refractive defects, but above all before the age of 65 the ability to accommodate is gradually lost and the power of the glasses must consequently be increased.

There are three types of glasses:

reading glasses or monofocal glasses, which can be easily purchased in pharmacies or supermarkets: they are the first solution that comes to mind, but it is not the recommended one as “prepackaged” lenses are generally purchased without an eye consultation, proceeding by trial and error;
bifocal glasses: they are used to correct both near and far vision (in the lower part they have a lens dedicated to reading), but the division of the lens is very clear and not particularly comfortable;
trifocal glasses: between the lower part dedicated to reading and the upper part for distance vision, they have a portion of the lens for medium distance vision;
progressive glasses: they allow you to see well at any distance, and are indicated for farsighted people who also suffer from myopia, astigmatism or other visual defects. The areas are harmoniously combined, without abrupt interruptions, and are therefore much more comfortable than bifocal or trifocal glasses.

In recent years, alongside glasses, specific contact lenses for presbyopia have firmly established themselves.

These are disposable and soft lenses, enriched with wetting agents (phosphatidylcholine or hyaluronic acid) and of the multifocal type.

They therefore serve to see well both near and far, and can also be used in the presence of other visual defects, but require about 15 days of ocular-brain adaptation (the latest generation diffractive lenses, on the other hand, are accepted immediately) .

An alternative to the use of glasses and contact lenses for the correction of presbyopia is represented by surgery.

There are two ways to go:

laser refractive surgery (PRK or LASIK)
intraocular surgery

Laser refractive surgery, which has long been used to correct refractive defects, modifies the curvature of the cornea by removing some tissue fragments.

These techniques can be performed with monovision intent, i.e. leaving the dominant eye corrected “for distance” and the non-dominant eye in a refractive state “for near”, or with multifocal intent, i.e. modeling the cornea creating an area of vision for far and near.

Intraocular surgery, on the other hand, places an artificial lens, an accommodating multifocal lens that lasts forever.

In both cases, recovery times vary from person to person and the treatments will present different indications depending on the age of the patient and his previous refractive status.

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