VISION PROBLEMS

The most frequent sight problems

There are different sight problems that are predominant in today's society - these are refractive errors of the eyes.

Myopia
Hyperopia
Astigmatism
Presbyopia

Myopia

Myopia or short-sightedness is a refractive error that causes blurred vision when looking at distant objects.

Myopia or short-sightedness is a refractive error that causes blurred vision when looking at distant objects. This is normally due to 2 reasons:
- the eyeball is too elongated
- the cornea curves more than normal
These aspects bring images into focus in front of the retina and not directly on it, making it difficult to see distant objects. Myopia or short-sightedness is corrected with a diverging lens, which places the focus of the image on top of the retina and, as a result, helps us see better.

EVOLUTION

Myopia or short-sightedness normally appears during childhood, and develops until the individual is 20 years old, at which point it tends to stabilise.
There are forms of myopia or short-sightedness deemed severe (above 7D) which, due to the eye morphology that is caused, must be regularly reviewed by a specialist, who must also be consulted in the event of any change in vision.
In any case, regular monitoring with the specialist is important to assess the evolution.

CORRECTION

Myopia or short-sightedness is corrected with a diverging lens, which brings images into focus on top of the retina and, as a result, helps us see better.
Depending on the number of dioptres, it is possible to use a reduced lens so that the thickness of the lens is reduced. The optician-optometrist is the best professional to provide advice on this aspect.

Hyperopia

Hyperopia or farsightedness is a refractive error that makes it difficult or impossible to see close up objects.

Hyperopia or farsightedness is a refractive error that makes it difficult or impossible to see close up objects. Its symptoms are similar to those of presbyopia or eyestrain (link), which appear in individuals over 40 years old due to the loss of accommodation (variation of crystallin lens strength that helps shift focus between distant and close objects) Hyperopia or far-sightedness is normally due to two reasons:
- the eyeball is too short, or
- the cornea is flatter than normal
These aspects bring images into focus behind the retina and not directly on it, making it difficult to see close objects. Hyperopia or far-sightedness is corrected with a converging lens, which brings the image into focus on top of the retina, which helps us see well without overstraining

EVOLUTION

Hyperopia may not display any symptoms in young people, since the capacity of accommodation of the crystallin lens allows them to focus up close. Although in certain cases, this overstrain of accommodation causes symptoms such as eye fatigue, headaches, etc., and is sometimes not enough for correct focus. Blurred near vision can occur in these cases. This symptom often emerges along with presbyopia, at which point the focusing ability of our crystallin lens starts to decrease symptomatically.

CORRECTION

Hyperopia or farsightedness is corrected with a converging lens, which brings the image into focus on top of the retina and, as a result, helps us see better.
Depending on the number of dioptres, it is possible to use a reduced lens so that the central thickness of the lens is reduced. The optician-optometrist is the best professional to provide advice on this aspect.

Astigmatism

Astigmatism is a refractive error that causes distorted vision of objects, regardless of whether they are near or far away.

Astigmatism is a refractive error that causes distorted vision of objects, regardless of whether they are near or far away. This is due to the fact that the curvature of the cornea is not the same in all meridians, causing two different images in the retina (e.g. vertical and horizontal). Astigmatism is usually linked to myopia (short-sightedness) or hyperopia (farsightedness)

EVOLUTION

The strength of the astigmatism is usually quite stable over the course of the individual's life, but its orientation may shift between the axes, therefore it is very important to correct to avoid potential discomfort

CORRECTION

The astigmatism must be corrected with a lens that has different curves at each of its axes.

Presbyopia

Presbyopia is the diminishing ability of the eye to focus on close up objects.

Presbyopia is the diminishing ability of the eye to focus on close up objects. This is due to the loss of flexibility of the crystallin lens, the eye's natural lens found between the cornea and the retina.

EVOLUTION

Normally the first symptoms due to this loss of flexibility appear in individuals over 40 years old, and continue to develop until they are 65 years old, when the accommodative capacity of the crystallin lens reaches its minimum.

CORRECTION

It is corrected by adding to the distance prescription to offset the loss of flexibility of the crystallin lens, which increases with age. The most common correction is with progressive lenses, which correct all refractive errors in one single lens.